America is a nation of couch potatoes. Nearly 80 percent of Americans do not get the recommended amount of physical activity, according to the Centers for Disease Control and Prevention.
People who do not exercise often say they are too tired to do so after a long day of work. But such sluggishness may itself be a sign that you need more activity, not less.
Contrary to popular belief, regular exercise enhances energy levels rather than depleting them, says Pete McCall, a certified personal trainer and health and fitness expert with the American Council on Exercise.
"To boost energy levels, the goal is to increase blood flow and oxygen consumption," he says. "When this happens, the body will be much more efficient at producing and using energy."
In fact, a 2008 University of Georgia study found that previously sedentary people who complained of fatigue saw their energy levels jump by 20 percent -- and their fatigue sink by 65 percent -- after beginning a program of regular exercise.
How exercise puts pep in your step
Of course, all of this is counterintuitive. Anyone who dreads sweating through a long run or struggling to pump iron likely wonders how such taxing activities boost energy.
But over the long haul, regular exercise promotes increased energy in several ways, McCall says.
- Expanding mitochondria and capillary networks. Muscles use oxygen to produce energy. Long-term exercise can expand the number of mitochondria in cells. Mitochondria use oxygen to produce energy for muscle contraction. Exercise also increases the number of capillaries, the smallest blood vessels. The capillaries are where oxygen diffuses from blood into muscle tissue.
- Increasing the efficiency of the heart and lungs. Exercise helps the heart and lungs become more effective at placing oxygen into the bloodstream and moving the oxygenated blood to the muscles in the body.
As these changes occur, "it becomes significantly easier to produce energy, leaving individuals with the feeling that they have more energy," McCall says.
Finally, some hormones and neurotransmitters help the body metabolize nutrients into chemical energy, which is then used to fuel muscle contractions.
"Long-term adherence to exercise helps improve the efficiency at which they're used to produce energy," McCall says.
Types of exercise that boost energy
McCall says many different activities can boost energy. He recommends 10 to 45 minutes of daily exercise at a level where you are able to talk comfortably while exercising (low-intensity) or where talking becomes more of a challenge (moderate-intensity).
Examples of low-to-moderate intensity exercise include:
- Cardiorespiratory exercise: walking, jogging, cycling or dancing
- Strength-training exercise: weight lifting, body-weight training, medicine ball training
Other examples of this type of exercise might include a brisk walk, dancing or simply playing with your kids for 20 minutes.
Higher-intensity exercise -- in which you can only talk in single-word answers, if at all -- can leave you feeling energized for up to three hours after your workout. However, after that, you may feel a wave of fatigue that lasts until six hours after the original workout.
Too busy to exercise?
What about people who say they are too busy to work out? McCall recommends breaking up your routine into shorter bursts.
"Only five to 15 minutes at a time can make a big difference," he says. "The goal is to
compile up to 45 to 60 minutes of physical activity per day, not at a single time."
He adds that routine daily activities -- walking to work, taking the stairs, standing for periods of time -- can qualify as part of this exercise.
People can burn up to 300 calories a day by engaging in such modest physical movement, McCall says.
"Brief periods of activity do add up," he says.