WASHINGTON (Reuters) - Couch potatoes who complain they are tired all the time have an easy solution -- a little light exercise. 

Regular, low-intensity workouts such as a leisurely stroll can boost energy levels by 20 percent and decrease fatigue by 65 percent, a team at the University of Georgia found.

"Too often we believe that a quick workout will leave us worn out, especially when we are already feeling fatigued," Tim Puetz, who helped conduct the study, said in a statement.

"However, we have shown that regular exercise can actually go a long way in increasing feelings of energy, particularly in sedentary individuals."

Puetz and a team led by Patrick O'Connor at the university's Exercise Psychology Laboratory studied 36 people who did not exercise regularly and who said they were always fatigued.

They were divided into three groups. One did 20 minutes of moderately intense exercise on an exercise bike three times a week for six weeks, the second did similar workouts but at a much more leisurely pace and the third did no exercise.

The low- and moderate-intensity groups had a 20 percent increase in energy levels over the non-exercisers, the researchers reported in the journal Psychotherapy and Psychosomatics.

To their surprise, the researchers found the low-intensity group reported better reduction in fatigue than those who worked out harder.

"It could be that moderate-intensity exercise is too much for people who are already fatigued and that might contribute to them not getting as great an improvement as they would had they done the low-intensity exercise," O'Connor said in a statement.

"A lot of people are overworked and not sleeping enough," he said. "Exercise is a way for people to feel more energetic. There's a scientific basis for it and there are advantages to it compared to things like caffeine and energy drinks."

Many studies have shown that exercise can boost energy, especially over time. O'Connor's team published a report in 2006 showing that exercise can reduce fatigue in patients with cancer, heart disease and other medical problems. This study looked at people whose fatigue did not seem to be associated with any medical condition.

(Reporting by Maggie Fox; Editing by Bill Trott)