Friday, February 24, 2012

How the Body Actually Reacts to Exercise



So far I've talked about the impossibility of using exercise to "burn" extra stored calories, as well as the the dangers of excess exercise. In this post, I'll be getting into how the body actually reacts to exercise.

Your Body Easily Adapts to Physical Activity
From your body's perspective, physical activity is an expected part of everyday life. The human body has evolved to interact with any environment it might find itself in. But the body has no idea what physical activity it might encounter: It might require lifting heavy things, sprinting toward or away from other animals, and/or walking for long distances. As such, the brain has to be able to adapt to this variable physical activity as well as adjust its lean mass to produce an adequately powerful, agile, and endurant survival machine that has just enough reserve fuel (fat mass) to make it through the lean times.

As a very intelligent organ, your brain can easily adapt to physical activity. Let's say that you exercise for an hour, burning 300 calories. Your body will lend you 300 calories from its energy reserves (fat and glycogen). After you are done exercising, your brain will sense that its energy stores are missing 300 calories, causing your hunger and appetite to increase. As you eat more food, you will pay back those 300 calories.

This means that regardless of the physical activity you engage in, your body weight should remain stable. Unless you need more muscle.

Physical Activity Builds/Repairs Lean Mass
When your body is unable to meet certain physical demands, it uses this feedback as a signal to grow more muscle (so long as you have enough nutrients and rest). However, if your brain senses that there is no longer a need for this extra muscle, then this extra muscle will be removed. So physical activity will adjust your muscle mass, which can adjust your body weight.

Exercise doesn't just build muscle, it also recycles existing cells. Through the process of autophagy, physical activity can stress poorly functioning cells. The body can then recycle these cells, improving their function. This may explain why those who exercise usually feel good, while those who are less active don't: Sedentary individuals lose much of their ability to recycle these poorly functioning cells.

Physical Activity Enhances the Brain
Exercise isn't all about your muscles. It also enhances your brain. Research is now showing that daily physical activity can:

Exercise Alone Can't Cure Overweight
If you are overweight, this scenario might make it seem like it is impossible to lose weight, but it isn't. You just have to understand that your body-weight (and body-fat) set points are out of whack. Another way of putting this is to say that despite the abundance of food you are eating, your brain's malfunctioning feedback systems make it seem as if you are constantly starving, causing you to constantly overeat.

In fact, engaging in exercise (especially chronic cardio) without fixing these broken feedback systems can sometimes make you gain more body fat if you are eating the wrong foods.

So, if you only remember one thing from this post, remember this: If you do not first repair your body's energy feedback systems (via diet and lifestyle changes), you'll never be able to lose all those extra pounds, no matter how much you exercise (or starve yourself).

Conclusion
You can't fool your body into burning "extra" calories with exercise. Exercise helps build/repair muscle, recycle poorly functioning cells, and improve the function of the brain. If you have extra fat weight, then your feedback systems for your body weight or hunger/appetite are not working correctly. This means that the only thing that can fix your extra fat weight is a proper diet.

However, when you combine a proper diet with an effective exercise program, then you can build a stronger body and improve your body composition (where you have more lean mass and less fat mass) at the same time.

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