When you’re feeling tired, do you gulp a cup of coffee, grab a nap, or go for a stroll? Walking is an effective way to recharge your batteries and restore your get-up-and-go. In fact, almost any exercise can help shed the fatigue that comes from too much sitting or standing. Just how does physical activity boost energy?

What research shows

It’s a myth that moderate exercise makes you feel tired. Moving around literally generates more energy inside your body. Our knowledge has greatly expanded in recent years about how this works.

Researchers have learned that exercise stimulates tiny organs called mitochondria inside your body cells to produce energy. The mitochondria act like miniature power plants, converting blood glucose into the energy needed for bodily functions.

Even more exciting is the discovery that the size and number of mitochondria that you have in your body is affected by your daily activity. Each bout of exercise signals your body to create more mitochondria as well as enlarge the ones you already have. Adding more numerous and larger power-generating units increases your ability to produce energy; that’s why regular exercise enhances the total amount of energy you have available.

Exercise improves mood

Physical activity can enhance energy in several other ways. First of all, exercise increases blood flow through your body, delivering more oxygen to your cells. The mitochondria in your cells need oxygen to make energy.

Secondly, exercise signals your brain to secrete neurotransmitters such as serotonin, dopamine and norepinephrine. A deficiency of these substances may contribute to energy-robbing depression. When depressed patients exercise, they’re able to increase internal production of these natural anti-depressants—without taking drugs, researchers have found.

With vigorous exercise, your brain releases endorphins—opium-like compounds that ease pain and produce a sense of well-being or even euphoria. The fitter you are, the greater the output of these mood- and energy-enhancing hormones.

How much does it help?

The findings are consistent. In one study, from the University of Georgia, inactive folks boosted energy by 20 percent and cut fatigue by 65 percent, simply by doing low-intensity exercise.

In another, a large analysis of 70 studies involving 6,800 people, sedentary people who completed a regular exercise program reported less fatigue than did groups that did not exercise. The effect, which was noted in both healthy and chronically ill people, was greater than that seen from using stimulant drugs.

Prevention take-away

Exercise is one of the best ways to increase energy levels and reduce fatigue. For optimum energy-boosting results, exercise at a mild to moderate intensity. Good examples include walking, dancing, golfing, group-fitness classes, yoga, Pilates, and Tai Chi. Too-strenuous of a workout may temporarily leave you feeling drained or fatigued.

Other tips: Talk to your doctor before beginning an exercise routine. Drink water before, during and after exercise sessions to reduce workout fatigue. And try exercising to music—the combination may be especially effective for elevating both energy and mood.

Lastly, find a variety of fun, simple activities you can do every day. Keep it up and you’ll likely discover exercise that recharges your body with energy.

For more information: American College of Sports Medicine, www.acsm.org.