The Runner's Body - Part 3, The Metabolic System

Did you miss the first two parts?
The Musculoskeletal System
The Cardiorespiratory System

Part 3 - The Metabolic System

The metabolic system provides fuel for the body in the form of energy. It enhances the body's fuel system by helping to store more energy, use it more efficiently, and supply energy to muscle in greater quantities and at greater rates.


Chapters:

~Maximum Fuel Economy: Discuss hitting the dreaded wall which occurs when the blood glucose level falls to almost nothing due to the depletion of glycogen stores in the liver and the muscles. This chapter also touches on my newest pet peeve that you should exercise at a lower intensity in order to burn more fat. The verdict? Not true. The authors advise that if your goal is to lose weight, you should concentrate on the total number of calories burned and not worry about the types of calories (carbs vs. fat). It works like this:

"After you complete a low-intensity workout in which you burn mostly fat, your glycogen stores remain fairly full, so few of the calories you eat during the rest of the day will be used to replenish your muscles' glycogen stores...but after you finish a high-intensity workout in which you burn a lot of carbohydrate, your glycogen stores are greatly depleted, and many of the calories you consume later in the day will be used to replenish these stores; few or none will be stored as body fat. And, in fact, your body is likely to break down some stored body fat to supply post exercise needs because the high-priority glycogen restoration would be slowed down if your body drew on carbs for those needs."

~All You Can Eat: Just because we are runners does not mean we can eat whatever we want. This chapter proposes a novel way to keep track of what we eat and provides advise on how to eat for optimal health and performance.

~Leaner, Lighter, Faster: Not all runners are build the same and there is not one optimum size/shape that works for everybody. This chapter describes how to determine the optimal body composition for your own body as well as how to optimize what you've already got. It also provides suggestions for the best recovery meals.

What I Learned:
~The amount of energy your body needs depends a lot on how fast you run because the faster you run, the more glucose you'll use.
~You can teach your body to burn more fat through training. A heavier reliance on fat means less reliance on blood glucose which = delayed fatigue and improved running performance.