Hormesis

Why are we so soft today? Why is it that our ancestors were able to perform feats like killing bears and wooly mammoths in snow-swept grasslands? How do present-day tribesmen withstand days of ultra-cold temperatures in Northern Greenland and prolonged periods without water in scorching hot Kenyan deserts? Why is it that a century ago, children in the Swiss alps ran barefoot through ice-cold mountain streams on cold days, while now they get carpal tunnel syndrome playing video games? How did they do all this without succumbing to the chronic diseases that are so rampant today? I believe part of the answer lies in hormesis.

Hormesis is the process by which a mild or acute stressor increases resistance to other, more intense or chronic stressors. It can increase resistance to a variety of stresses, not only the one to which you are exposed.

It might sound like a foreign concept, but you're more familiar with it than you think. Exercise is a form of hormesis. It's a stress placed upon the body that increases resistance to a number of other stressors: physical exertion, cardiovascular disease, depression, diabetes, age-related cognitive decline, neurodegenerative disease, etc.

Intermittent fasting is one of the most promising forms of hormesis. It's consistent with the variable energy intake our hunter-gatherer ancestors probably experienced. As with some other forms of hormesis, it has broad-ranging effects on health and stress resistance. Alternate-day fasting, a version in which food is available for 24 hours ad libitum and then not available for the next 24 hours, increases mean lifespan in mice under some conditions without reducing calorie intake. It increases resistance to neurodegeneration, stroke, myocardial infarction, toxins, cancer and diabetes in rodents. It increases the expression of heat shock proteins and SIRT1, both implicated in general stress resistance. Basically, it makes them tougher all-around.

Although only a few studies have been performed in humans, IF looks promising for preventing or reversing diabetes, cardiovascular disease, overweight and possibly other health problems. It can also decrease fasting insulin and increase insulin sensitivity considerably. I fast for 24 hours, once a week. No calories, only water. It's not a form of caloric restriction, because I eat like horse the day after fasting. It's just a mild stressor that toughens my body to other stressors.

I also take cold showers. Here the scientific data are more sparse, but it has a long history of use as a form of "body hardening". I do it to increase my cold resistance by firing up my non-shivering thermogenesis. It seems to be working. It certainly wakes me up in the morning! Have you ever noticed how you can get into cold water and be surprisingly comfortable once you're used to it, even though you're practically naked and water is conducting heat away from your body 20 times faster than air would? That's probably your non-shivering thermogenesis kicking in.

There are probably many other ways to induce hormesis. Do any of you have techniques to share? By the way, hormesis is one of the central tenets of homeopathy. Solid principle, incorrect application. I'd be happy to sell anyone sugar pills for 50% less than his or her local homeopath is selling them. I promise mine are equally effective...

Soft living makes a soft body. Give it some controlled stress from time to time!


Thanks to Kirill Tropin for the CC photo.

Nature's Laws

Last night I was watching a little video clip of the Jack LaLanne show. LaLanne was an advocate of strength training and whole foods nutrition whose TV show ran from the 1950s through the 1980s. In the clip, he describes how his father died an early death due to heart and liver disease. A quote that really stuck with me was when he said his father died due to "disregarding nature's laws". That pretty much sums up my philosophy. Live in a way that generally mimics what our genes evolved to thrive on. Why did our paleolithic ancestors have strong, healthy bodies? Why are there still cultures that are free of chronic disease to this day, even into old age? Because they are following nature's laws. Break the law at your own risk.

Jack LaLanne and I do differ a bit on what constitutes a natural diet. For example, I don't throw out my egg yolks... But hey, the man is 94 and going strong. Here's another quote of his: "If man made it, don't eat it". Words to live by. Quite literally.

Eagle Creek

Last weekend, I went on a 3-day backpacking trip with some friends. We endured rain, snow, difficult river crossings and a vicious mouse attack, but managed to have a good time nevertheless. Here are a few pictures:

Punchbowl falls

Tunnel falls

Basalt cliffs

Apparently mice like cheese!

Vaccines

I am a label reader. Whenever I'm thinking about buying food in a box, which is rare, I typically read the whole label to look for sinister ingredients. So when I got a booster vaccine for tetanus last week, naturally I asked for the product information.

Along with a nice dose of tetanus and diphtheria toxoids, my medial deltoid received 0.28 mg of aluminum, up to 0.3 micrograms of mercury, and up to 100 micrograms of "residual formaldehyde". I got the vaccine because I like being able to chew, but I wasn't able to lift my arm for several days. I don't know if that was due to an immune response to the tetanus and diphtheria (probably) or if it was caused by the aluminum, mercury and formaldehyde they injected into my arm.

We work with formaldehyde in my lab, and I can tell you it is not to be messed with. I had to take an entire training course just to use it, during which I learned that if there's enough of it to smell, it's toxic. 0.1 parts per million in the air is enough to cause a burning sensation in the mucous membranes. We always use it in the fume hood. Formaldehyde is a toxin, a carcinogen, and a teratogen (causes birth defects). So I'm sure you'll understand why I wasn't too happy about having 100 ug of it injected into my body.

I'm not criticizing the concept of vaccines, I just wish they'd make more of an effort to clean them up!

Exercise Didn't Keep Us From Getting Fat

One of the surprising things I noticed when I was poring over data from the NHANES survey (US CDC National Health and Nutrition Examination Survey) from 1975 to 2006 is that the number of inactive people has diminished in that same time period from 50% to 24%. This is shocking to most people. We have this romanticized idea that in the 1970s people were more active, as if everyone chopped wood and walked 15 miles to work in the morning. The reality is, there were office jobs, housewives and cars without the large numbers of runners and gym-goers we have today.

Granted, NHANES data are self-reported and should be taken with a grain of salt. However, Chris at Conditioning Research pointed me to a study looking at changes in energy expenditure from the 1980s to the present in North America and Europe. It doesn't suffer from the same biases because it's based on direct measurement rather than self-reporting. Here's the executive summary: we're expending slightly more energy than we used to, partly because we exercise more and partly because it takes more energy to move our heavier bodies around.

I'm certainly not blaming the obesity problem on an increase in physical activity, but I do think we can safely rule out inactivity as the reason we've gotten fatter. In my mind, this only leaves one major possible cause for the obesity epidemic: changes in diet. Don't get me wrong, I think exercise is good. It has numerous positive effects on physical and mental health. But it's not as powerful of a tool for fat loss and general health as diet.

Anecdotally, I do know several people who lose fat when they exercise regularly. I also know some who don't lose fat when they exercise. Exercise and a healthy diet converge on some of the same metabolic pathways, such as sensitivity to insulin. But diet changes are far more effective than exercise at correcting metabolic problems. The reason is simple: the problems a person corrects with a good diet are caused by a poor diet to begin with.