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How Energy Works
Have you ever wondered why the exercises you do to improve your level of fitness and build energy often leave you feeling fatigued and sometimes sore? A total picture of energy actually involves a cycle of activity, fatigue, and recovery. Each of these is an important consideration when planning your fitness program.
Activity
Sudden strenuous activity or muscle exertion relies on muscle stores of carbohydrates for immediate energy. One by-product of burning this sort of fuel for energy is lactic acid, which can cause fatigue and a burning sensation in the muscles. Your body requires oxygen to remove lactic acid, so if you continue to exercise beyond your body’s ability to provide adequate oxygen, the lactic acid can build up and cause moderate to severe muscle pain. You are also apt to feel short of breath and rapidly fatigued.
Fatigue
Fatigue, or lack of energy, can be affected by many factors including the length and intensity of activity. Illness, stress, anxiety, depression, improper nutrition, lack of sleep, boredom and even long periods of inactivity can contribute to fatigue. When you start a new activity you may become fatigued more easily until your body adapts to the new energy needs. Similarly, if you exercise during hot weather, you are apt to become fatigued more quickly, since much of your body’s energy is being used to cool itself down (through sweating). When you reach the point of fatigue, don’t push yourself further. It is your body’s warning that it is time to take a break and recover.
Recovery
When you become physically fatigued, your body needs time to recover. That doesn’t mean lying down and putting your feet up, but merely decreasing the intensity of your activity to allow your body to rest and recuperate. For instance, if you feel fatigued during aerobics class, stop and walk around the room until your breathing returns to normal and your heart rate begins to subside. If you follow a vigorous, long-term aerobics program, alternate the days that you do aerobics with other types of activity, such as strengthening and flexibility exercises. Building adequate recovery time into your fitness plan can actually result in quicker gains and less risk of injury.
Understanding the cycle of activity, fatigue, and recovery is an important aspect of your total fitness plan. It takes your body anywhere from 24 - 48 hours to recover from an "all-out" workout, and it is during this recovery period that the physiological changes that improve your level of fitness occur. Working out too hard, too soon can actually harm your progress. Don’t shortchange your fitness goals by pushing too hard. Remember, recovery from fatigue is as important to fitness as activity or exercise itself.
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