The Primal Blueprint (9 page)

Grok spent several hours each day moving about at what today’s exercise physiologists might describe as a very low-level aerobic pace. He hunted, gathered, foraged, wandered, scouted, migrated, climbed, and crawled. This low-level activity prompted his genes to build a stronger capillary (blood vessel) network to provide oxygen and fuel to each muscle cell and readily convert stored fat into energy (fat is the main fuel used for low-level aerobic activity). His daily movement also helped develop strong bones, joints, and connective tissue. What Grok did not do was deplete his energy and muscle glycogen supply with sustained efforts that were even moderately taxing. This counterintuitive behavior could have left him vulnerable to a predator, starvation, or some other misfortune.

Today most of us either are too sedentary or conduct workouts that are too stressful and misaligned with our primal genetic requirements for optimum health. The exercise gospel for decades has been to pursue a consistent routine of aerobic exercise (jogging, cycling, cardio machines, group classes, or any other sustained effort), supposedly leading to more energy, better health, and weight control. However, too many lengthy workouts at elevated heart rates (between 75 percent and 95 percent of maximum) can put you at risk of exhaustion, burnout, injury, and illness. The high-carbohydrate diet required to perform these workouts day-in and day-out only adds to the problem. At the extreme—such as with the overtrained marathon runner or ironman triathlete—a commitment to fitness can actually accelerate the aging process.

Overexercising is a common scenario when you consider how our active population has such strong focus, dedication, and willpower to push through signs of fatigue. Our bodies are simply not adapted to benefit from chronic aerobic exercise at intense or even mildly uncomfortable heart rates nor to slog through exhausting circuits of resistance machines several days a week. The mild to severe difficulty of these Chronic Cardio or strength workouts overtaxes the stress response (commonly referred to as the fight-or-flight response) in your body. Here, your pituitary gland tells your adrenal glands to release cortisol into your bloodstream. Cortisol is a powerful stress hormone that is critical to a variety of physical functions and energy production. The spike of cortisol in the bloodstream from a stressful event increases respiration, heart rate, blood circulation, and mental focus and even converts muscle tissue into glucose for quick energy. This is a great example of how we abuse a system that was genetically designed to respond to emergencies, such as Grok facing a predator.

Even today the fight-or-flight response is highly desirable and effective in the face of true danger or peak performance stimulus, such as a modern Olympic athlete crouching in the starting blocks or an emergency worker summoning superhuman strength for a rescue effort. Unfortunately, when the stress response is triggered repeatedly (by the constant hectic pace of modern life coupled with workouts that are too long, too difficult, or too frequent), your adrenal glands can so overproduce cortisol that they eventually become fatigued and release less-than-normal levels of cortisol and other hormones critical to many aspects of health. Thyroid hormones and testosterone also decrease from prolonged stress, resulting in a decline in energy levels, loss of lean muscle tissue, a suppressed immune system, and the general condition best described as burnout.

The uplifting—but actually catabolic (“breakdown”)—effect of cortisol in the bloodstream is the reason many people feel fantastic for about four to eight weeks following a severe exercise and diet program. Initially buoyed by the short-term performance-enhancing effect of high cortisol levels, they will typically crash and burn when the adrenals become exhausted by unrelenting stress. This “cortisol story” is an extremely important factor in balancing fitness with health (no, they are not the same!) and enjoying a long, disease-free life. I discuss the subject in further detail in many areas of the book and also in the Q&A at
MarksDailyApple.com
.

Regarding weight-loss goals, the notion of burning calories through chronic exercise to lose weight has proven to be flawed. Overexercising increases your appetite, particularly for quick energy carbs to address your chronic depletion of stored energy. This pattern of stressful exercise and extra eating results in a body fat stalemate—not a good return on investment for all that hard work!

What our genes truly crave is frequent movement at a slow, comfortable pace: walking, hiking, easy cycling, or other light aerobic activities with a heart rate range of 55 percent to no more than 75 percent of maximum. These efforts are far less taxing than the typical huffing and puffing, struggling and suffering exertion level that we’ve been conditioned to think leads to fitness. Find ways every day to move more often—walking (even across parking lots, instead of cruising for a close space; take the stairs instead of the elevator—it all adds up over a lifetime!), hiking, swimming, easy cycling, or anything else that moderately elevates heart rate. Strive to accumulate two to five hours per week of low-level exercise. More is better as long as you have the time and can resist the temptation to “go hard.” If possible, make an effort to go barefoot frequently to develop natural balance, flexibility, and leg strength.

Grok’s life demanded frequent bursts of intense physical effort—returning gathered items (firewood, shelter supplies, tool material, and animal carcasses) to camp, climbing rocks and trees to scout and forage, and arranging boulders and logs to build shelter. The biochemical signals triggered by these brief but intense muscle contractions prompted improvements and adaptations in muscle tone, size, and power.

Today, following a strength-training program featuring natural, total-body movements (squatting, lunging, push-ups, pull-ups, etc.) helps you develop and maintain lean muscle mass, increase metabolism to maintain low levels of body fat, increase bone density, prevent injuries, and enjoy balanced hormone and blood glucose levels. An approach of short-duration (always under an hour, but often lasting only 10-30 minutes), high-intensity workouts—conducted fairly regularly but without excessive regimentation (always aligned with your energy levels)—will produce superior results to a routine of going to the gym too often for workouts that last too long. The latter is a recipe for fatigue and undesirable gene expression. You can enjoy extraordinary benefits doing as little as two focused, intense 25-minute sessions per week, with minimal risk of overtraining or mental burnout.

In a primal world where danger lurked around every corner, Grok’s ability to run was a strong indicator of whether he would live long enough to pass those superior genes down to the next generation. Whether he was dashing off to avoid a charging herd of mastodons or running down small game for dinner, Grok’s occasional sprints triggered gene expression within fast twitch muscle that enabled him to sprint a little faster the next time. That which didn’t kill Grok made him stronger. Take that, Nietzsche!

Today occasional maximum effort sprints help increase energy levels, improve athletic performance, and minimize the effects of aging by promoting the release of testosterone and human growth hormone (these are beneficial for women as well as men). Once a week (or more frequently if you are an experienced athlete), when energy and motivation levels are high, choose a simple, brief session and go all out! Examples include sprints on hills, grass, or beach; plyometric drills; and intervals on a stationary bike. We’ll detail many other options in
Chapter 6
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Our ancestors’ activity and sleep patterns were shaped by sunrise and sunset. Days started early (they actually caught the worm…and ate it!), and after the sun went down, it was safer to huddle together and rest. Furthermore, hunter-gatherers required plenty of downtime to repair and rejuvenate from their active lifestyles. Studies of modern hunter-gatherers suggest it wasn’t always an uninterrupted eight hours either. It’s likely that Grok slept together with his family or a small tribe, sharing a night watch for predators and tending to the needs of crying babies. The occasional afternoon nap was also available when the urge hit, with no guilt about what else he should really be doing.