One of the effects of intense exercise on your body can be improved fitness. Your dietary practices may determine how beneficial intense exercise is; poor diet can even make intense exercise detrimental. Intense exercise affects your metabolic, endocrine and immune systems. It also depletes your body's energy stores, and makes your body hungry for recovery nutrients. Seeking out recovery nutrients and replenishing energy supplies becomes top priority after intense exercise. Consult your doctor before beginning any new exercise regimen.
Glycogen
Intense exercise may completely deplete your muscles of glycogen, a source of energy derived from carbohydrates in your diet. When you do not ingest sufficient carbohydrates immediately after an intense exercise session, your body must break down and covert body proteins and body tissue into glucose to meet energy demands. This processes effectively eats away at your muscle tissue, and produces toxic ammonia, which, the National Federation of Professional Trainers explains, puts additional stress on your liver and kidneys. Given sufficient carbohydrates, the effects of intense exercise bring glycogen stores above pre-exercise levels, which boosts your performance.
Metabolism
Intense exercise can help you control your weight or reach weight-loss goals, by increasing your resting metabolic rate. Your metabolic rate increases by 12 to 24 percent after intense resistance exercise, exercise biochemistry expert John Berardi explains on the T Nation website. Your metabolism increases proportionally with the amount of muscle tissue your body has. Resistance exercise can also speed up your metabolism for as long as 36 hours after each workout session, further boosting your calorie burn.
Hormones
Intense exercise produces desirable increases in anabolic hormones --- which help you build muscle --- and hormones that increase blood circulation. Concentrations of anabolic hormones, such as testosterone and growth hormone, increase proportionately with the intensity of exercise. Intense resistance-exercise sessions can also raise your levels of cortisol --- the so-called "stress hormone" that's been linked to weight gain --- by as much as 100 percent over resting values, Berardi warns. Ingesting a carbohydrate-rich supplement immediately after intense exercise may help keep cortisol levels down. Consult your doctor before taking supplements of any kind.
Immune System
Intense exercise damages muscle tissue, and your immune system responds by disposing of dead muscle tissue and build new muscle to repair the damage and adapt to the demands of your exercise session. Intense endurance exercise may also weaken your immune system for up to 72 hours after exercise, warns a 2001 report by the President's Council on Physical Fitness and Sports. This period of altered immunity may increase your susceptibility to viruses and other bacteria, but ingesting carbohydrate-rich supplements --- with your doctor's approval --- after exercise may help offset undesirable immune-system changes.
References
- T Nation: Precision Nutrition for 2002 and Beyond; John M. Berardi
- "Personal Trainer Certification Manual"; National Federation of Professional Trainers; 2008
- Bodybuilding; Fat Loss Wars; Shannon Clark
- Bodybuilding; Bodybuilding and The Endocrine System; David Robson
- President's Council on Physical Fitness and Sports; Does Exercise Alter Immune Function and Respiratory Infections?; June 2001
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