Obesity and Lifestyle Change - Thinking About Activities

In previous posts we have discussed how people use time, their patterns of activity, and how these relate to their well being. These discussions have focused a great deal on how activities influence mood, or how they can serve to reduce stress. Less has been said about how activity influences our heart, lungs, nervous system, bones and muscles and other physiological systems.

I hasten to point out that this is not a post about exercise and physical fitness. The body is a complex system, with many individual subsystems working together to explain that complexity. Ordinarily, we think of the brain as the control center. But we seldom think of the back office systems that influence how the brain works. One of these back office systems is the endocrine system. This system regulates the chemicals in our bloodstream that carry messages to the nervous system. It influences metabolism, tissue growth, development and mood. Scientific discussions about how stress harms the body focus directly on this system of alerting or message sending through hormones. This brings us to the main topic of this post—obesity

Obesity is a significant health problem and it can be described as a kind of banner or symbolic indicator of how activity and lifestyle in the 21st century can influence health in both beneficial and harmful ways. Obesity is an epidemic, and if you visit the website of the Centers for Disease Control (CDC), you will see a dramatic illustration of how the incidence of obesity has spread across the country over the past two decades. The data clearly suggest that obesity is not just a regional phenomenon, nor a socio-economic phenomenon. It is a lifestyle phenomenon that is related to how people spend time to consume and expend energy. If you notice in the CDC chart how the prevalence of obesity has spread, states where there are more outdoor opportunities for hiking, skiing and kayaking, or more farming and ranching— seem to be the last places where the obesity epidemic arrived. That suggests environment (and activity opportunity) influences obesity. But we are getting ahead of ourselves here. There is another important factor related to weight gain—hormones. Especially hormones resulting from living stressful lifestyles.

Without going into too much detail or repeating information available widely on the Internet, most diets (the usual approach to battling weight gain) fail. Why? Because hormones signal our body to store energy (or calories) so that we can survive famine conditions. These systems are ancient, biological survival mechanisms that evolved over millions of years when humans were hunters or gatherers. Animals in the wild have the same systems, but they spend their awake hours in a quest to find food just as humans once did. They may go for days in their quest for meals, burning more calories than they are able to replenish. Contrast this with the modern life of humans in the U.S. and other developed nations: Going for hours without a meal is often viewed as a starvation diet!

Thus, animal species (including humans) are biologically wired to store calories and resist efforts to expend them. All dieters know that as soon as they begin reducing their food intake, their body reacts by increasing its efforts to hold on to those life sustaining calories. That's what makes dieting so difficult. But food intake is only half of the equation.

The other part is energy expenditure. As modern conveniences are developed, technology becomes our enemy. We move less, watch TV or surf the Internet more, and there is little calorie burning to offset our increased consumption. Moreover, eating itself is an activity, and a pleasurable one. Generally, people would rather eat than work out on the treadmill. Eating is also typically a social activity. When people get together to enjoy themselves and each other, food is often involved.The result is increased body weight. Exercise intentions expressed in New Year resolutions are, well— well intended. But habits and routines are hard to break. People need stimulating reasons to live their lives differently. They need to be motivated to move more and eat less.

But the story doesn't end there. Stress (and there is a lot of that around lately!) produces hormones that signal the body to conserve energy. So metabolism (calorie burning) slows as a result of stress too. Some scientists attribute the obesity epidemic as much to increased levels of stress (and the influence of stress hormones on slowing metabolism) as they do to lifestyle patterns that are characterized by sedentary activities and increased food consumption.

So, at long last, we get to the point of this post about obesity. Obesity is more than weight gain. It is a condition of lifestyle that is affected by factors that have nothing to do with eating. The interesting thing is, these factors involve human activities, and the most natural solutions have to do with the activities people do as they live their everyday lives. If those activities help people burn more calories and eat less, so much the better. But if they give pleasure, reduce stress, and stop signaling the body to store energy, they provide a double benefit. The bottom line: Activity is more than exercise!

Stress is not good for you...not that you thought it was!!

If there is anything that can be said about life in the United States these days (or the world, for that matter), it's that there are lots of things going on that can cause worry or concern. It is a scientific fact that the most unhappy people in the population are those who are unemployed, so it should be seen as a societal concern that the unemployment rate is rising to levels not seen for decades. The new administration understands that the cost for not doing something will be far greater than the cost of an economic stimulus package, no matter how large. Why? Well, it's not just because people need to earn a living and buy things to get the economy back on track. It's also because economic downturns can affect public health by making the population more susceptible to illness.

But this blog post is not about politics or economic stimulus proposals. It's about stress and what it does to our bodies over time. We all generally perceive that being stressed out is not a good thing. But perhaps many of us feel that as long as we can get beyond the stressful periods and have some time for R&R (rest and recuperation), so to speak, we can shake off the consequences of stress and there will be no harm done.

The truth is, however, that over time, the effects of stress add up. It takes a toll on the body. And scientists now have a way of measuring that "toll" through objective means. These tests, which include blood pressure, cholesterol, and several other measures of "physiological" fitness, are collectively called "allostatic load". When the body responds to stressful circumstances, that process is called allostasis. Medical and psychological understanding of how stress shortens our lives and makes us susceptible to acute illnesses and longer term chronic diseases has now advanced rapidly. Scientists now have a better understanding of how the process works, and the area of "psychoneuroimmunology" or PNI, is where this knowledge is being gained.

The theory of how our worries activate hormones to tax our immune systems is too involved for this blog, but I recommend that interested readers take a look at a good book written in an interesting, understandable way called: Why Zebras Don't Get Ulcers, by Robert Sapolsky, PhD. The title of the book is a shorthand way of communicating the relationship between stress and health. Part of the reason we overtax our immune systems is because we worry about things that have happened to us or might happen to us. That worry signals our body to activate stress hormones that are good when they are needed, but harmful if they are around when they aren't needed. Dr. Sapolsky uses the example of the fire station that runs out of fuel and fresh men when it is constantly responding to false alarms, and compares that fire station to our immune systems, which are supposed to stamp out germs and other invaders to keep our bodies healthy. Immune systems get worn down by high and persistent levels of stress.

So...as my son once told me: "chillax". That was good advice. People who are able to chill and relax, are more resilient to the adverse consequences of stress. They experience less wear and tear on their bodies, and chances are, they will be more likely to live longer and healthier lives...and thus be able to "do life well." It turns out that resilience, or the ability to endure stress with fewer adverse consequences, is related to happiness. But that is a topic for a future blog post. Stay tuned!

(For readers interested in a readable but more complete and scientific account of allostasis and allostatic load on the web, go here.)