The philosopher Friedrich Nietzsche said "that which does not kill us, makes us stronger," and recent research seems to back him up. The right levels of stress can dramatically fortify your ability to fight infection, prevent cancer, and live longer.
While we have traditionally considered stress harmful to our health, a new understanding has turned things upside down. Our biggest problem is too little stress. I know this sounds absurd. "Try finding someone who suffers from a lack of stress," you say.
Well, it's all about the form and quantity of the stress.
In order to make sense of this story you have to look at the environment in which we developed.
For the vast majority of human existence (99 percent) we lived in a world that bore little resemblance to our contemporary one. As hunter-gatherers we regularly experienced food shortages, temperature swings, and the need for daily physical activity. These conditions provided the training camp for our biology. Evolution crafted an animal adapted for this scenario.
Our contemporary environment assures easy access to a smorgasbord of excess calories, controlled temperatures, and practically no need for physical activity by comparison. This once was called progress. We marveled at our success in taming the world. It now seems that these victories directly contribute to our biggest health problems: obesity, diabetes, hypertension, cardiovascular disease and a diminishing health span.
We've been so damn clever it's literally killing us.
We have eliminated the stressors that provide our fitness. Intermittent food shortage, temperature fluctuation, and a daily dose of physical activity define the stresses that optimize health. The concept of this kind of adaptive stress response is known as hormesis.
Let me give you an example. The most successful method for extending an animal's lifespan is caloric restriction. By significantly decreasing food intake, lifespan lengthens. This stressor triggers a cellular stress response that renders the animal more resistant to chronic diseases and slows aging. One of the ways this works is through a dramatic decrease in inflammation. We now know that inflammation characterizes the early stages of most chronic diseases.
Another powerful demonstration of hormesis can be seen with exercise. While exercise causes some low-grade oxidation and inflammation in the short term, it demonstrates powerful anti-inflammatory effects in the long term. Researchers studied the effect of exercise with and without the antioxidants vitamins E and C. When exercise was preceded by the administration of these vitamins, the beneficial effects were eliminated. In other words, blocking the mild insult of the exercise voided its therapeutic effects.
We often presume to know why certain things are good for us. But when it comes to lifestyles, proving what is good and why proves quite difficult. Only recently have we begun to appreciate how hormesis appears to explain much of the health benefit of vegetables, fruits and nuts.
In a way, plants are black belts in the hormesis department. Because they can't move away from environmental stressors, they have developed a magnificent arsenal of adaptive responses to such stressors as UV radiation (sunlight), fluctuations in hydration, soil nutrients, temperature and a variety of infections. And they have had about 1 billion years to hone these responses. That dwarfs our time on the planet. It's no coincidence that one-third of the top 20 drugs on the market are plant-derived. In eating plant foods, we benefit from the compounds they make in response to their stressors. And because plants and humans evolved in the same environment (earth), their stressors have been our stressors.
Unfortunately, we consume very few plant foods by comparison to our hunter-gatherer days. In addition, the plant foods we do eat are not wild. We have done to our food what we have done to ourselves. In cultivating our crops, we create optimal conditions for their growth and survival. This has decreased their stress and therefore the good stuff that they can pass on to the consumer.
So what can you do with this information? Do you need to don a loincloth and return to the Serengeti?
Here are some steps that this data suggests would be beneficial. But make sure you consult your doctor if you have any medical issues.
- Do something physical every day. Interestingly, because the activity pattern of hunter-gathers is long periods of slow pace, interspersed with intense exertion, interval training with a similar intensity pattern best mimics this stressor. And don't take your vitamins right before exercising.
- Eat lots of vegetables every day. The less industrial the farm source, the better.
- Consider decreasing how much you eat. Research has shown that alternate-day fasting can be as effective in stimulating hormesis as longer fasts. If you want to start in slowly, you could try skipping breakfast once in a while. This prolongs the overnight "fast" with minimal adjustment.
- Try turning down the heat a bit and run cold water at the end of your shower. You don't have to join the polar bear club right off the bat!
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