Here’s the thing, though. For most people, all that hard work is largely unnecessary and there is a more effective, balanced, and simpler approach to fitness.

For most folks, the ones who want to bang out consecutive pull-ups, climb several flights of stairs without losing their breath, go on a three-hour hike for fun, run a few miles if they feel like it, keep up in pick-up games of [insert sport here], go skiing/snowboarding/surfing/waterskiing, or just generally be comfortable dealing with the physical demands of everyday life, a little bit of efficient, targeted, concise activity goes a long way. I’d even say that most people have far more to lose than they do to gain by throwing themselves into a hardcore fitness regimen – the type that monopolizes your time, inhabits your thoughts, and forces you to reconstruct your life to accommodate its presence.

My whole outlook on health, fitness, and nutrition is founded upon the notion that it doesn’t have to be difficult to be healthy. I’d even say that obsessing over eating and exercising turns the process into just another stressor we have to deal with, and reducing stress is just as important to our health as staying active and eating right. In my opinion, then, keeping things simple isn’t an option for Primal folks; it’s the only way to do it. It’s the whole game. It has to be easy, simple, and effortless to work. There’s no point in making yourself miserable just to lose weight or pump out a few more reps, when following a few simple fitness rules, eating right, and tinkering with some easy lifestyle hacks will get you most of the way there. To break it down further:

• 80 percent of your genetic potential for body composition is determined by what you eat. You’ve probably heard me say this in the past. Eat Primal and you’re almost there.
• Five more percent of your body composition can be further influenced by how much sleep and leisure time you get and how you moderate your stress levels. Lifestyle stuff.
• 10 more percent of your genetic potential for body composition will come from smart exercise: Lifting Heavy Things, Sprinting, and Moving Frequently at a Slow Pace.

With minimal effort and time commitment, conducting a Primal Blueprint Fitness routine of bodyweight exercises, sprints, and low level movement will take you to the next level of your genetic potential, after achieving tremendous results through Primal eating and lifestyle. Sounds easy, right? It is, and that’s the whole point!

• The final five percent of your potential body composition/physical performance is achieved with more advanced training and highly specialized athletic goals. We’re getting into hours-long gym session, pain and punishment territory.

Can we really call our conventional ideas of physical perfection perfect if they come with so many downsides for so many people? What good is “elite” if maintaining that level of performance means you’re not available to enjoy the rest of your life? Is that last five percent really necessary? Do you need that eight-pack, or is the six-pack good enough?

The point here is that you can get huge results with minimal effort and that incremental improvements beyond that demand a disproportionate amount of effort and commitment, and a come with host of other downsides.

If elite performance is your ultimate goal in life, then sure, go that extra mile and give it all you’ve got. Some people truly derive happiness and fulfillment (and, if they’re lucky, a living) from the pursuit of extreme physicality, and to those folks, I say godspeed. I was one of them for many years, but that changed when I realized the cost-benefit ratio of my endurance lifestyle was becoming severely imbalanced. Don’t let me stop you, but heed my words of caution all the same.

In just a couple weeks, I’ll be releasing Primal Blueprint Fitness (for free, of course). It will flesh out all the things I’ve hinted at in this post and in the past by presenting a fitness plan that is sustainable, simple, effective, and smart. It’s designed to work for the people who want a good strength-bodyweight ratio, to look good naked, and be fit enough to go for a long hike or run a 10k at a moment’s notice. It will provide steady, measured progression, but also variety in the form of constantly shifting Workouts of the Week (WOWs) to be posted each Monday here at Mark’s Daily Apple. It will make you work hard, but you won’t work long. It will stress intensity over volume and quality over quantity. In short, it’s designed to get the most people the fittest they can be in the shortest amount of time possible. PBF may not make elite athletes out of you, but, along with diet, lifestyle, and stress-mitigation, it will get you 95% of the way there. From that point, you can take things up a notch to reach that elite level, or you can chill out and enjoy a long, active existence.

And so, I ask once more: Is attaining elite physical performance worth the costs incurred along the way? For me, for most of you, and for anyone who just wants to be healthy and stay active for life, the answer is a resounding no.

Don’t give into the same flawed Conventional Wisdom for your fitness plan that you’ve already rejected with regards to Chronic Cardio – that more is necessarily better. In my estimation, there is a better way. One that defines fitness in the broader context of overall health and life quality. One that delivers impressive results with simple, novel hacks. And I’m confident all this can be achieved through PBF. In the coming weeks, you’ll have the chance to try it on for size. Until then, Grok on!

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No related posts.

Also in the last four weeks my team and I have begun to further solidify the PrimalCon 2011 agenda. Needless to say we’re going bigger and better this time around. I’ll be leaking updates between now and April 2011, but think Survivor-style team challenges, after-dinner dance parties, personal massages, group ocean plunges, lavish Primal feasts, educational seminars, and a good dose of rest and relaxation all at a beautiful beachside resort in sunny Southern California. There will be plenty for beginners, Primal veterans and all skill levels alike. Come to kick start or re-energize your Primal lifestyle, learn a ton of valuable information you can apply in your life immediately, and connect with some of the friendliest, like-minded people you’ll ever meet. Learn more about PrimalCon 2011 here.

There are only 3 days remaining to save $100 off the total registration price and space is going quickly so reserve your spot today.

P.S. If you’re interested in payment plans or have any questions contact my office at 310-317-4414.

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3. PrimalCon 2010 Announcement: Sit, Stand and Walk Like Grok

From a leisure standpoint, what did Grok’s world look like? Although researchers admittedly work from limited remnants, there’s actually quite a bit we can surmise about hunter-gatherer cultures. Hunter-gatherer societies varied – and continue to vary – considerably, but the overall picture is far more elaborate than you might think. There’s the cave art, of course, which in many cases reveals impressively intricate narratives of cultural history as well as myth. Then there’s the pottery, baskets, bags, boxes and paddles among other practical items that that display aesthetic as well as functional character. Add to this the ornately carved spears and other weaponry, totem poles and rattles to signify social status and accomplishment. Finally, there are the costumes, masks, body paints and other ceremonial items that some of Grok’s contemporaries used for celebratory and spiritual occasions. Oh, and let’s just throw in a 12,000 year-old temple for good measure. Not what they taught you in school, eh?

Yet, beyond the concrete (and often surprising) accomplishments were the more common pastimes: socializing, dance, music performance, storytelling, sleep, and play. Yes, Grok as beach bum. (I knew there was a reason I liked him so much.) Although often criticized by colonizers and earlier anthropological researchers, hunter-gatherers’ leisure activities served integral purposes to the social stability and survival of the community. Socializing, music and celebration strengthened communal relationships. Story-telling passed down a sense of tribal history and cohesion as well as technical knowledge their ancestors had learned for living off the land. Napping through the heat of the day helped members conserve resources, while activity at night helped keep predators at bay. Play honed physical skill and fostered a cooperative culture within the group.

The point here is not to put the hunter-gatherer existence on a pedestal or to declare them executive geniuses of time management. I’ve said numerous times before that there is much I don’t envy in Grok’s existence, the constant threat of ferocious predators being the most obvious. Nonetheless, there’s something to be gained, I think, in contemplating the disparity between our lives and those of our ancient ancestors. Our modern culture with its penchants for motion, commotion, individualism, productivity and specialization tries to sell us the idea that this is normal and ideal – that it’s not the way it’s always been only because it’s the pinnacle of ever moving progress. We’d better keep up, or we’ll be left behind. Even the little free time we do have is too often filled with the obligatory chores of modern life: yard keeping, house cleaning, car maintenance and endless errands. As for vacations and longer breaks, we better come back with a good story or we clearly just wasted good time. The modern practice of leisure is co-opted by achievement.

Shouldn’t leisure be more enjoyable, more life-giving, more leisurely? When it comes to real R&R, what can our ancestors’ example teach us? For example, we sometimes imagine that if we can just “manage” our time better and organize our lives better that we’ll be happier and more relaxed. Maybe we need less to manage in the first place. (That goes double for the kids.) We need more impressive weekend plans. Then again, maybe we should just spend more time sprawled out in the grass laughing with the kids or curling up with our partner. A Sunday afternoon nap. Lounging at the beach – or in a kiddie pool – in the backyard. Simple but scarce pleasures, I guess.

What do you want to do more of this summer? Have you filled your leisure quota, or do you feel like the summer’s gotten away from you? What role does leisure play in your Primal life? Lessons you’ve gleaned from Grok’s example?

I’ll look forward to your comments. Thanks for reading, everybody, and have a great week!

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Hi Mark – first, I know you’ve got a gob of emails beckoning you….I just hope that you can get back to me at some point I love reading your blog, so much so that I’ve decided I would like to pursue a career as a nutrition consultant – in natural health of course. I’m so glad there is such an option! Perhaps some of my friends and family would pay a bit more attention if I study & earn a certificate instead of my continual praises of your site and how it’s changed my life. To you and your Bees, my gratitude!

Now, the reason I am messaging you:

I’m soon to be planning my wedding! Excitement in itself, of course. While trying to plan a menu chock full of primal food (and not have the guests even realize they are eating healthy ‘gasp!’), it’s a bit daunting. So far, I love the Chicken Poppers as an offering. I want to do mostly appetizers, less waste of food. Anyway, I have searched your posts to see if there were any suggestions for such an event, and I couldn’t find any. So if I have overlooked one, my apologizes! If you could point me in a direction of a blog that might have such a post, I would be delighted! Or if you have time to offer some other ideas, great! If not, then once I scour the ‘net for hours and days and weeks in search of such items, I’d be happy to share with you here so that other couples will have to do less work.

Any help you can give, I would be oh so happy! Thanks again, Mark!

Jennifer

I already responded to Jennifer (good luck with the wedding!), but I figured expanding my response into a full-fledged post on Primal wedding fare might help others with impending nuptials.

Before I discuss the food, let’s dig into other considerations. Every aspect of the wedding matters, not just whether you replace the mashed potatoes with mashed cauliflower or turnips.

First of all, get the proper Primal dress code established. Shoes? Not allowed. And that goes for bride, groom, and guest alike. No one is exempt, not even grandpa with his Velcro orthopedics. Sorry. This will be new ground for most people, though, so be sure to give advanced warning of the shoe ban on the wedding invitations. A combination of comic sans, bolding, and underlining should get the point across. Vibrams are acceptable, of course.

Don’t walk down the aisle at a steady pace. Instead, make it fractal! Run, stop, sprint for a bit, slow to a crawl. Alternatively, you can make it a full-blown sprint to the altar. Whatever you do, do not jog at a steady pace with an elevated heart rate.

Also: no chairs, pews, benches, or other sitting contraptions. Some ceremonies last upwards of two hours, and that’s plenty of time for the negative metabolic effects and muscle lengthening caused by excessive sitting to manifest. Just have them all stand.

When you toss the bouquet, make sure to propel the flowers with a snap of your hips, as if you were performing a kettlebell swing. Most wedding planners will tell you differently, but the bouquet toss is not about your arms at all – it’s all in the hips…

Of course, I’m being playful here, but upon rereading this I’d say these and other novel Primal wedding ideas (shaman, anyone?) would make for a riot of a ceremony. But enough with Primal daydreaming. Let’s move on to the food.

The classic wedding main courses are actually pretty Primal, tending to revolve around large chunks of animal flesh. You’ve got your prime rib, your salmon, your rack of lamb, your steak, or your roasted chicken, and I highly doubt any of my readers would object to any of those dishes. Sides generally include a garden salad or perhaps a soup, along with veggies and a starch. Bread is served, but that can easily be ditched altogether and I doubt they’d even notice. All in all, the standard wedding menu works pretty well so long as you stick to hunks of meat and vegetables, skip the bread, and moderate the starch.

If you’re going with outside catering (as most people do), you’ll just have to be vigilant about the preparation methods they use. Since you’re paying good money for their service – and it’s your day – insist that butter and olive oil, rather than “cooking oil,” be used to cook. Tell them wheat is to be avoided, and if they balk, pull the celiac card (it works every single time). The better catering companies will fulfill every request you make of them – they’ll do the cauliflower gratin, the pureed butternut squash, the olive oil mayo – but you will have to pay for it. If you go with the in-house fixed menu that comes with the venue you may be able to get some extra vegetables instead of those French fries along with your butter/olive oil request fulfilled, but don’t expect any massive substitutions.

But that’s not what Jennifer wanted. No, she wanted to wow her guests. She wants to “trick” them into eating “that fad diet” for a day – and she doesn’t want them to know it. Your standard plate of meat and vegetables isn’t going to convince anyone of the efficacy of eating Primal, but a reception filled with Primal appetizers will reach even the most jaded and skeptical taste buds.

New takes on classic finger foods are my personal favorite.

Primal Chicken Poppers – Don’t forget to make the ranch.

Coconut Shrimp with Chive Mayo

Peppers of all kinds

Sunflower Sesame Crackers

Cheese! For those that can tolerate dairy it has a place in the Primal eating plan. On top of that everyone loves it. But how can we get guests to eat a wedge of brie without a wheat-based cracker to go with it? Here are a few ideas.

Fruit, especially grapes, apples, pears, and figs, is excellent with cheese (and prosciutto).

You know how when you sauté a cheeseburger in your cast iron pan and the cheese oozes off the burger and onto the pan and gets all crispy? If you were to engineer that process, perfect it, and expand it on an industrial scale, you’d get Joyful Abode’s Baked Cheese Crisps.

Meatza, or some other pizza replacement.

Salads are perfect, actually. Make a big batch and serve in small bowls with forks, or make it truly finger-friendly by providing fresh lettuce or cabbage as edible middlemen.

Your choice of ten dressings.

Curried Chicken Salad

Bacon, Chicken, and Avocado Salad

Make a seaweed salad.

Summer makes for beautiful weddings and sweaty pits. Beat the heat as you bask in it with:

Halibut, Snapper and Shrimp Ceviche

Heirloom Tomato Gazpacho

Paleo Shrimp Cocktail (with sauce)

Short ribs are short in stature, but not in flavor or tenderness. These delectable morsels of cow flesh make excellent appetizers. Some of them have even got handles! I’ve really been digging in lately. Here are a few ideas:

Primal Braised

Korean-Style (go for the blackberry version, and serve with lettuce wraps, AKA beef-n-leaf)

Beef Candy

Appetizers, tapas, finger foods, small plates – whatever phrase you use to describe it, food variety is insanely popular. When people eat small plates, and lots of them, conversation is stimulated. People are mobile and more social, rather than locked into a seating arrangement and awkward silence. The food gives them something to talk about. “Did you try the…?” You’ll never hear that one when everyone has the same roasted chicken, carrots, and rice. Plus, as Jennifer points out, an appetizer-based wedding reception means less waste. For the most part, you’re just popping these dishes into your mouth, or taking at most two bites to finish the job. If you don’t like it? Tough, because it’s already in your stomach.

People like finger food. They like eating with their hands. Perhaps they crave that visceral connection with their food, or maybe they just want to get messy in a socially-acceptable manner. Either way, a room with a steadily replenishing supply of Primal finger food will be the perfect spot to launch a successful, lasting marriage between two Primal people.

I didn’t intend for this to be the definitive guide to wedding food or anything, so if you need more ideas, do some snooping. Both Joyful Abode and Girl Gone Primal produce some incredible recipes; visit both and get inspired. Free the Animal’s “Food Porn” section is a go-to source for full-fledged Primal meals, if you decide to go the more traditional route. There are dozens of other resources out there, of course, on the slim chance that the aforementioned don’t satisfy your needs.

If you don’t have it already, I also recommend both the Primal Blueprint Cookbook, which is chock full of great recipe ideas, and the newly minted PB Recipe index, which contains pretty much every recipe we’ve ever posted. Between all that, you should be covered and your reception should be a smashing success.

Hit me up with your Primal wedding menu ideas and links in the comment board. Thanks, everyone, and Grok on!

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Richard Nikoley just got back from MovNat, and so did Melissa McEwan! Read about Melissa’s adventure, and then read all five parts of Richard’s (part 1, 2, 3, 4, and 5).

For those of you who had fun building your own protein bar over at YouBars, you’ll probably enjoy SlantShack, which lets you build your own beef jerky.

Ready for some inspiration? Watch Veronica Garza’s story about overcoming an autoimmune disease through lifestyle habits.

Ready for more inspiration? Read J.D. Moyer’s story about overcoming asthma through lifestyle habits.

Ready for even more inspiration? Read how you can overcome depression through lifestyle habits. That’s right, even The Guardian is starting to go Primal.

And finally, as Healthcare Epistemocrat discovers, job interviews haven’t changed much in tens of thousands of years.

Recipe Corner

• Girl Gone Primal knows the words well, “Everything is better wrapped in bacon.” This week it’s bacon-wrapped mini-frittatas.
• In the “Primal substitutes for snack foods” category, Nutty Kitchen makes spiced butternut squash fries.

Time Capsule

One year ago (July 18 – 24)

• The Definitive Guide to Saturated Fat – Long standing whipping boy of Conventional Wisdom, this post explains why saturated fat is not the enemy of health.
• The Savagely Effective Mace – Nope, not the stuff you spray from a can. This post is about the heavy, metal thing you swing at your enemies. It just happens to be a great workout tool as well.

Comment of the Week

I don’t know about all of this, Mark. As an arbitrary spot, I don’t think I would feel safe seeing a bunch of humans sneaking up on me. Especially since I can’t move…

-Arbitrary Spot from 5 More Ways to Playfully Mimic a Persistence Hunt

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Beef liver has a stronger flavor than chicken liver, but in the scheme of things is still pretty mild. The flavor and texture of beef liver is at its best when cooked until firm but still a bit pink. However, even if you overcook these patties slightly they will still be moist and flavorful. Evelyn’s addition of grated potato, celery root, carrot and onion doesn’t so much hide the flavor of liver as it enhances it. Fry these liver hash brown patties up in a pan of butter and we’re betting even the pickiest eaters in your house will want to try a bite. Perfect for breakfast or dinner, delicious dipped in a little mustard or hot sauce, or better yet, garnished with sautéed onions and mashed lingonberries, like Evelyn does.

Of course, Evelyn’s lucky enough to live where lingonberries are plentiful. Lingonberries are members of the cranberry family and grow wild in regions like Scandinavia, Canada and parts of the northern United States. The tiny, tart red berries are rarely sold fresh in regions where they do not grow, although lingonberry jam can often be found. If you’re like us and couldn’t find lingonberries at your local market, you can still enjoy Liver Hash Brown Patties with a side of Evelyn’s coleslaw. The crispy texture and tart-sweet flavor of coleslaw is just right with the richness of liver.

Ingredients:

• 1 pound minced beef liver
• 1-2 raw potatoes, peeled
• 1 raw carrot, peeled
• A fist-sized piece of celery root, peeled
• 1 onion
• 1 tablespoon fresh marjoram or 1 teaspoon dried
• A pinch of black pepper and salt
• 1-2 tablespoons melted butter or olive oil

Instructions:

Grate the vegetables and mince the onion. Mix these with the minced liver. Add spices and melted butter.

Heat butter or oil in a pan and drop small portions of the liver mixture into the pan to form patties. Fry the patties several minutes on each side until nicely browned.

Evelyn’s Coleslaw

Ingredients:

• 1 cabbage, grated
• 2 carrots, grated
• 1 granny smith apple, grated
• 1/2 – 1 cup hazelnuts, crushed
• 1/4 – 1/2 cup raisins or dried cranberries
• 1/4 cup white balsamico, white wine vinegar, or cider vinegar
• 1 tablespoon warm water
• 1 teaspoon honey
• 1/2 cup sour cream
• 1/2 cup mayonnaise
• 2 teaspoons mustard
• 1 teaspoon horseradish
• Salt and pepper to taste

Instructions:

In a large bowl mix together grated cabbage, carrot and apple with hazelnuts and raisins.

Whisk together remaining ingredients and pour over coleslaw. Mix well and enjoy!

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The mice that lived in the enriched environment showed “reduced tumor growth and increased remission.” In fact, the tumors in the “enriched” mice were half the size of the standard cage group after only three weeks in the stimulating environment. After six weeks, the tumors of the “enriched” mice were one fifth the size. Furthermore, the researchers could see no tumors at all in a fifth of the enriched environment group at the end of those six weeks.

The enriched environment, the researchers discovered, “upregulated” the BDNF gene (hypothalamic brain-derived neurotrophic factor), which helps regulate appetite and energy. Mice raised in standard cages didn’t show as much BDNF activity as their enriched environment counterparts. The researchers then found that the “enriched” mice also showed “downregulation of leptin production”. The enriched environment, they determined through further testing, activated the BDNF/leptin axis, which then resulted in tumor regression for the enriched mice. When the researchers studied a third group of mice that couldn’t naturally produce leptin and then administered leptin to the group, their tumors grew substantially larger than a control group given saline.

But wait, there’s more. It’s a lesson crucial for living the healthiest Primal life possible. The physical activity of the mice in the enriched environment wasn’t what made the difference. In fact, when the control mice were allowed to run in a wheel, their corticosterone levels (stress hormone) dropped below the consistently higher levels seen in the enriched environment mice. The researchers attribute the discrepancy to “good stress” – the healthy challenge – of enhanced social interaction and intellectual stimulation in the enriched environment as opposed to the pure physical exercise allowed to the controls.

That’s right: it appears that the good stress of positive social and intellectual challenge can inhibit leptin production and associated cancer growth. You can tick off all the more “concrete” tasks of a healthy lifestyle (e.g. diet, exercise), but in the end you need to have a life too – with some constructive, character-building stress.

So often, we get overwhelmed by the responsibilities of our lives. We attack the day with task-orientation and then lament feeling bogged down by the succession of endless chores. Although few of us can completely clear our slates for the week, eventually, the to-do list can morph in an ongoing attitude. We feel overrun by “bad stress.” Yet, maybe it’s more a question of balance. We put off meaningful investment in ourselves as well as our relationships and family time. We tell ourselves we can live off reserves for now – the memories of previous experiences, the benefits of old adventures – while we meet other, more pressing obligations. I dare say that our psychological selves run down just as our physical selves do. Reserves don’t last indefinitely. The spirit, as well as the body, needs continual sustenance.

It’s worth asking, how enriched is your environment right now? Do you do a job or volunteer work that’s fulfilling and/or pleasantly challenging? Are you engaged in hobbies that call on your creativity? Do you take in events or activities that move you in some way – whether it’s a ruckus-rousing football game or a suspenseful book? Do you go the extra mile in your relationships and family to make some fun and adventure? When was the last time you felt like you’d really learned something? Grown from something? Cultivating genuine happiness isn’t a selfish endeavor. Investing in your personal development – even in the midst of a busy, responsibility-filled life – isn’t an egotistical indulgence. If we can feed the mind (remember law #10!) and spirit, we bring more – more energy, more inspiration, more motivation – to the daily tasks of life. Greeting them in a renewed, even changed frame of mind, we might see them differently. Good stress helps us balance out and even diffuse the bad stress of life. We’re happier – and healthier – as a result.

On that note, Grokkers, go forth, and relish your weekend! Grab it with both hands and run like mad. Make a memorable experience –and maybe even a great story – out of it. Does this have you thinking – stirring – planning? Share the love in our comment section before you bust out, and thanks for reading today.

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I can’t recall exactly where I heard about it, but it was someone’s offhand reference to the notion of the calls of songbirds affecting our circadian rhythms that convinced me I should do a follow-up to the blue light piece from earlier this year. The notion of bird calls affecting us on a deeper level than a regular sound makes some intuitive sense to me, so I did some searching to see if there was anything to it.

There’s certainly a precedent for the phenomenon in animal research. For years, researchers have known that auditory cues exert potent entraining effects on the circadian rhythms of animals. Sounds from a “large animal colony where there were many cats and people,” for example, entrained the circadian rhythms of isolated domestic cats, while common house sparrows’ circadian locomotor rhythms were entrained by the playback of pre-recorded bird song. In squirrel monkeys, the zeitgeber effect of sound cues becomes pronounced when the master pacemaker is partially disabled. So the mechanism clearly exists in certain mammals and birds, but what about humans?

I was only able to find one study, but it’s a good one, and the full text is free. Take a look for yourself.

Ten subjects spent two 4-day lab sessions in constant dim (read: not a significant source of photic entrainment) light. Between 1 AM and 3 AM, before the core body temperature minimum was reached, on the second and third nights of each session, half were subjected to a 2-hour CD of bird calls set to classical music at an intensity equivalent to normal human conversation (this wasn’t blaring. overwhelming noise); the control half were subject to a blank CD they were told contained an auditory stimulus “above the human hearing range.”

Both groups experienced delays in dim light melatonin onset (DLMO) – “a reliable marker of circadian rhythm phase” – and core body temperature (CBT) phases, with the group receiving the auditory stimulus experiencing significantly greater delays. Self-reported feelings of fatigue were also lower in the auditory stimulus group. These results mark the first (and, to my knowledge, only) recorded incidence of auditory cues stimulating circadian phase shifts in humans, “with shifts similar in size and direction to those of other non-photic stimuli” more commonly researched.

Light is the granddaddy of zeitgebers, consistently producing the most amplified phase shifts when compared to non-photic stimuli, but it’s notable that the study’s auditory stimulus produced phase delays that were “consistent in direction with those produced by light.” That is, light input has been shown to induce phase delays (lowered melatonin, delayed “sleepiness” when presented before CBT minimum and phase advances (increased melatonin, advanced “sleepiness”) when presented after CBT minimum. While this study only tested the effect of bird song on circadian phases before CBT minimum, its similarities with light input suggest that bird song might advance the circadian phase if presented post-CBT minimum. That wasn’t tested, though, so we don’t yet know for sure.

Furthermore, most circadian studies of light input employ longer and/or more frequent light pulse durations when compared to the sound study, which may explain the difference in phase shift amplitude. In fact, when you compare this study to studies that use light in similar amounts, the amplitude of circadian phase delay is “of similar magnitude.” It appears as if sound cues have great potential as circadian zeitgebers.

Another question the study’s author raises is whether the source of the sound matters – would we see the same effect on circadian phases if the subjects were presented with a CD playing the soothing sounds of rush hour traffic? Or what if you dropped the classical and kept the bird songs, or vice versa? Is it the mere presentation of auditory stimuli – any auditory stimuli – that matters? Would a two hour conversation with someone else do the trick?

An interesting question, eh? For me at least, it’s not difficult to imagine that specific sounds – like those we would have heard over tens of thousands of years of evolution – may have more of an effect on our millions-of-years-in-the-making circadian rhythms than random, more evolutionarily novel noises. Note that in previous animal studies, researchers were sure to use auditory stimuli that “made sense” to the animals in question: cat sounds for cats and bird songs for birds. As anyone who’s woken up in nature (camping in the mountains, maybe, or deep in the rainforest) can attest, wildlife tends to erect a wall of sound, especially in the morning. You can’t escape it, and any early human ancestors living in the wild would surely have grown up knowing, hearing, and experiencing the sound of birds and other animals on a daily basis.

I mean, we don’t “just wake up.” Hormones, regulated by the circadian clock and entrained by light, sound, and other cues, wake us up.

I don’t usually use an alarm clock. For those rare occasions when I do and as a test, I recently downloaded a new bird chirp ring tone to use as my morning alarm clock instead of the annoying stock tone. I haven’t taken any body temperature or melatonin phase shift measurements, but it certainly is pleasant to wake up to the sound of bird song. This makes me wonder about alarm clocks in general. What’s really happening when we’re awoken by the alarm? I know that the basic shock of a sudden noise (any noise) is what wakes us up initially, but what if a “soothing,” more evolutionarily-congruent sound can make that wake up experience more pleasant and less jarring by shifting our circadian phase, too? Does morning light wake us up through brute, mechanical force, or does it tug at our circadian pacemaker, urging it to produce more cortisol and less melatonin?

This is exciting stuff. Nerdy stuff, sure, but exciting. And, of course, speculative. I’m going to stick with the bird song wake up call and see where it takes me. If anyone else gives it a try (maybe with real birds), let me know how it turns out.

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You might recall a previous MDA series on how blue light can affect our circadian rhythms, and what we can do to maintain normal, natural levels and timing of blue light exposure. Long story short – it turns out that our exposure to blue light is akin to exposure to daylight, and getting too much – or too little – at the wrong times can disrupt our natural circadian rhythm and affect the quality of our sleep by changing when melatonin is secreted in our bodies. In other words, blue light is a major human zeitgeber (the ten-dollar word of the day); an exogenous cue that synchronizes our internal clock. But it’s not just light that affects our circadian rhythms.

The master mammalian circadian pacemaker is located in the hypothalamus, in a section known as the suprachiasmatic nucleus (SCN). Lesser circadian pacemakers with their own 24-hour cycles, sometimes called slave oscillators, have also been located in the eyes, pineal gland, liver, intestines, and other organs, but the SCN is said to synchronize them, employing over 20,000 neurons in the process. The SCN receives input via three main pathways: the retino-hypothalamic tract, which directly delivers photic (light-derived) information; the geniculo-hypothalamic tract, which indirectly delivers photic information; and the raphe-hypothalamic tract, which uses serotonin to deliver non-photic information to the SCN. The SCN tells the pineal gland to secrete melatonin. Both photic information (like blue light) and non-photic information (like temperature, social cues, food availability, to name a few) act as zeitgebers with the ability to entrain (circadian synchronization in accordance with an outside cue is called entrainment) internal clocks. We’ve already covered the photic side of things (which also happens to be the most powerful), so let’s take a look at how some non-photic zeitgebers affect your internal clock and what you can do to entrain your own circadian rhythm.

Feeding

Just as the sun rises and falls, the availability of food come in cycles, too. Indeed, research suggests that food availability cycles entrain organisms’ circadian rhythms. The classic example is the “early bird” who “gets the worm.” How does it “know” to wake up at the hour most advantageous? The bird doesn’t actively plan to wake up at a certain time and head out for grub(s). The availability of the food (in this hypothetical case, early morning) conditions the bird’s circadian rhythm to prompt an early morning wakeup. We see this in rodent models, which display distinct “food anticipatory activity” in the hours just before their regular mealtime, even if the SCN is damaged or removed, offering evidence of a separate, independent “food-entrainable oscillator” that responds to food intake schedules. We see similar results in mammal and primate studies.

As for humans, food-modulated C-peptide increases correlated with reductions in melatonin, the “sleep hormone”. In another study, patients with night eating syndrome (those folks who eat in their sleep) also showed delayed melatonin secretion. (Side note: They also showed delayed circadian onset of hunger-blunting leptin as well as advanced circadian onset of hunger-stimulating ghrelin secretion. Leptin release was delayed by one hour and ghrelin was bumped up five hours! Eating at night may have weight-gaining implications, but this is another post entirely). Eating late at night can phase shift your circadian rhythms by blunting melatonin secretion. So if you’re having a tough time sleeping consider not eating too late.

Exercise

In animals, activity levels affect circadian rhythm. Using body temperature regulation as an indicator of circadian phase shifts, we see evidence of the zeitgeber effect of physical activity in nocturnal animals put on a daytime activity schedule. Whereas nocturnal animals typically have high body temperatures and activity levels at night, forcing them onto a diurnal activity schedule causes body temperature to rise during the day and fall during the night. Their circadian rhythms are adjusting to the new schedule.

Evidence on exercise’s circadian effects in humans is less conclusive, but still present. One study identified nightly exercise (three 45-minute bouts of cycling) as an effective phase delayer of melatonin/sleep onset, and another showed similar results. One group of researchers was able to effectively convert night workers onto a daytime sleep schedule by controlling light input and using hourly bouts on the bike to phase delay the onset of circadian melatonin and body temperature rhythms. Strangely, one study showed that evening and nocturnal exercise actually resulted in melatonin increases, or advances in circadian phases – I wish the authors had given details on the exercise protocol so we could understand the apparent anomaly. Still, most studies do show that delaying the onset of circadian melatonin rhythms is achievable through exercise. Whether that’s a desirable outcome is up to you to decide. Night workers may want to play with nocturnal exercise.

Social Cycles

Can interactions between organisms cue circadian entrainment? Most likely. Researchers generally agree that circadian clocks developed primarily in response to the daily cycles of the environment – and, for most organisms, the environment includes not just light, dark, and temperature, but also the rhythms of and interactions with predators, prey, parasites, and community. For example, when two previously isolated deer mice, each with a different circadian rhythm, were placed in a common enclosure, they developed a mutual synchronization of their internal clocks. Honeybees forage in synchronicity with the rest of their colony, but isolated members tend to drift away from established foraging schedules, suggesting an important role for social entrainment. Members of numerous species show signs of metabolic synchronicity when in close contact with each other, including honeybees, beavers, bats, and even humans. In fact, something called the Social Rhythm Stability Hypothesis proposes that disruptive social events (deaths, break-ups, even minor disturbances of a person’s normal routine or of those around them) can entrain a person’s circadian rhythm and, in sensitive individuals, lead to bipolar disorder. It’s also interesting to note that one common treatment for bipolar disorder, lithium, is also one of the only known substances to directly affect a person’s circadian rhythm.

We are incredibly social animals – just think of how important the village, the tribe, the community, the family and language are to our identity as humans – and we are shaped by our interactions with others. It’s no surprise that social cues can have physiological effects on our circadian rhythms, too.

Temperature Cycles

Temperature cycles often correspond with light and dark cycles, but there is evidence that temperature acts independently on certain species’ circadian rhythms. Temperature cycles entrain the rhythms of drosophila, a type of small fly; of the leafcutter bee; and of the circadian-mediated locomotion patterns in certain lizards. Note, though, that these guys all share a common trait: they are not homeotherms. They rely on exogenous sources to regulate their body temperature. Very few mammals, other than maybe the pocket mouse and a kind of heterothermic (exhibits partial self-regulation of body temperature) bat, show significant circadian response to external temperature cycles, probably because they are largely homeotherms with the ability to self-regulate body temperature, as well as the temperature of the SCN pacemaker. When you put an SCN in a Petri dish and expose it to temperature fluctuations, the neurons respond. Thus, the human SCN is shielded from ambient temperature fluctuations, but body temperature fluctuations (even those driven by the clock itself) may affect the clock. Human core temperature is related to our circadian rhythms, but the ambient, environmental temperature cycle to which we are subject does not seem to affect the rhythm.

Regardless – extreme heat does make it hard to get to sleep, and I’ve always preferred crisp, cool bedroom air, so temperature does matter. Just not so much to our master pacemakers.

Sound Cues

It turns out that sound cues play a potentially large role in human (and other species’) circadian cycles, but I’ll discuss that more thoroughly tomorrow.

So What Does This All Mean?

Photic input remains the primary determinant of human circadian rhythm. You keep artificial (especially blue) light usage to a minimum as you approach your bedtime, make sure to get some natural (or even artificial blue) light in the mornings, and you’ll have taken care of most of your sleep-related circadian rhythm concerns. Just keep in mind that non-photic input matters, too – perhaps not as much as light, and the effects in humans are still being tested – and playing around with the peripheral rhythms might give you an edge. Tinker, as I often suggest (or even thinker, a la the Healthcare Epistemocrat), especially if you suspect your rhythm is off and you’re getting bad sleep. Otherwise, don’t get too haphazard with the hacking. Our circadian rhythms are pretty hardy, but it’s always smart to exercise caution when messing around with physiological systems our best and brightest are still figuring out.

The following hacks are worth testing:

• Intense exercise right before bed may suppress melatonin and delay the phase cycle. If your find yourself restless and too alert after your late night workouts, try earlier workouts.
• Conversely, if duty beckons and you need to be alert and awake one night, an extensive exercise session enjoyed right before normal bedtime should suppress melatonin and prevent sleepiness.
• Eating also appears to suppress melatonin secretion, so if you’re having trouble sleeping consider eating earlier in the evening.

You’ll just have to find what works for you. The good news is that we are pretty darn adaptable, and fretting over workout or meal timing (as long as we don’t run marathons before bed or eat entire meals at 3 AM) is probably tougher on us than simply allowing our circadian rhythms to respond, react, and adapt to all the various zeitgebers we’re faced with every day.

This is a pretty big topic and new research is still coming out. This post was meant to introduce you to the topic at large. Let me know if it’s something you’d like to see covered in more depth in the future.

Stay tuned for tomorrow’s post on sound cues and circadian rhythms. Grok on!

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Of course, that’s not what I’m suggesting at all. Few of us will ever participate in an actual persistence hunt, so I wrote last week’s post to encourage people to start thinking about movement in a different (but wholly ancient) way. Framing a workout in this manner will shape your journey, and it’s the journey that I’m most interested in – the actual nuts-and-bolts of varying speeds, changing gaits, fractal pacing.

I’ve noticed something in the way people, even folks in the Primal community, think about fitness. It’s all about the goal, that end point, the PR, the progression to a higher weight/faster time/longer run. You can’t undo a lifetime of fitness platitudes in an instant, after all. I think that’s part of being human – the drive to improve oneself. It’s not everything, though. Humans are also explorers. The journey compels us, sometimes for no other reason than the journey – the sights, sounds, and random incidents along the way – itself.

Why limit yourself to one or the other? Fitness should be about both the journey and the end result. It should be about the achievement of a goal (thirty consecutive pull-ups, a single pull-up, climbing Mt. Everest, climbing out of bed pain-free, whatever you choose) and the process of getting there. That’s why I think the persistence hunting model is so useful. It forces you to put aside the end result (because there isn’t actually a kudu at the end of the trail, and you aren’t actually going to invade the personal space of an innocent jogger) and focus on the journey. Live in the moment from time to time. It’s good for you.

Here, then, are five ways to emulate the persistence hunt without actually hunting anyone.

1. Pick an arbitrary spot, rather than a jogger.

Pick a spot, any spot. Maybe a landmark up ahead, like that knotted old tree just before the bridge. Run, jog, walk, sprint, leap, roll, and crawl your way to it. Keep things random and fractal. You won’t have the visual cue of an actual jogger this time, so imagination is paramount. It’s likely that your sanity will still be questioned by those around you, but at least your intentions won’t be. Let’s just hope trees aren’t actually sentient enough to get creeped out by a stalker.

Best part? You can wear jeans and a sweatshirt, and the tree will still love you.

2. Pick Spot, rather than a jogger.

Remember my post on the fractal exercise habits of dogs? Grab your dog, or borrow one from a friend, and take him or her on a run. Since most leashed dogs will simply run at the pace of the person holding the leash, you’ll need an off-leash, dog-friendly area for the full effect. It’s also important to convey the right state of mind. Dogs, as we know, have a weird, almost preternatural ability to feed off the energy of their owners. You feel down, it’s likely your dog will notice. When you’re excited and jumping around, your dog follows suit. Use this to your advantage and get yourself amped up. If your dog is the type to follow you dutifully without ranging too far ahead, you may have to psyche yourself up before your dog gets the idea. Leap around, jump, slap the ground, growl, grab your dog by the neck and shake him a bit, grab the scruff of the neck (every dog owner knows how to get their dog amped up) – just help your dog unlock the wild, individual, lupine spirit within, then let it loose.

Once your dog is off, sniffing things, rummaging through brush, and curious about everything, follow behind. Run when he runs, stop when he stops, climb where he climbs (lifting your leg where he lifts his leg and squatting where he squats isn’t necessary, however). Every once in awhile, take off sprinting so your dog gives chase. Switch things up to keep the energy level high.

3. Go free running.

This takes real imagination and whimsy, but it’s also potentially the most rewarding way to “hunt”. Kids can do this with their eyes closed (until they’re reprimanded by the cold hand of societal expectation), and we adults are really just big, grown-up kids, so there are no excuses. Just pick a suitable running surface – something that you’re willing to run, jump, and even roll around on – and start running. Open spaces, as opposed to designated trails or paths, are better, because an important part of free running is the freedom part. Or maybe you’re a contrarian; if so, choose a path and willfully stray from it.

If you can’t seem to get yourself going without some target or reference point, initiate the run with the following schematic: jog, walk, sprint, crawl, jog, walk, sprint…. At this point, you’ll find your imagination unencumbered and ready to create new movement patterns.

4. Use your Chronic Cardio buddy.

A few people in the comment section mentioned taking advantage of that one friend who simply will not listen to your anti-Chronic Cardio overtures, and I love the idea. Grab a friend who loves monotonous movement and use him or her as your stalking buddy. Tell them to run normally so you can proceed as outlined in last week’s post.

Better yet, plan your persistence hunting around your friend’s exercise schedule. If you know when he or she takes their daily jog, show up and stalk them, unannounced. You’ll get the benefits of hunting an unwitting participant without the potential negatives of stalking a total stranger.

5. Play catch with yourself.

This one sounds weird, I know, but bear with me. Go to a beach, a grassy field, or any open space with enough room to run for a minute or so in all directions. Grab a ball (tennis, rubber, etc) and throw it as high as you can and a bit in front of you, so that you have to run or jog to catch it. Catch the ball, then throw it again, this time a bit farther. Run a bit faster to catch it. Keep this up, making it a fluid, smooth thing – you catch it on the run and toss it back up and catch it again, always in motion. Mix things up and do somersaults and jumps (over sandcastles or kelp piles, perhaps). Chase the ball like your life depended on it. Dive if you have to. Do not let it touch the ground.

I find it works best on a long stretch of beach, right along the water, so that the sand is firm but forgiving and perfect for quick sprints, light jogging, diving, falling, and tumbling. Vary your speed by changing the trajectory of the ball. Test yourself for stretches by really throwing it far, then slow things down to a walking pace with high, short throws.

I hope I’ve avoided anything too controversial with this one (the showing up unannounced bit might draw a few comments!), but I’m sure you guys will let me know. Try these out and let me know how it works. Also, include any other persistence hunting/fractal running exercise ideas I might have missed. Grok on!

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