Heart disease is the leading cause of death for Americans, and stress is a major factor in developing the disease.

Experts have a plethora of advice for reducing stress and anxiety levels -- but what works best?

Recently, most experts have agreed that a moderate to low amount of regular exercise can ease personal tension and stress. But a new study by researchers at the University of Missouri at Columbia found that a relatively high-intensity exercise works best in reducing stress and anxiety that may lead to heart disease.

And women may benefit more from high-intensity exercise than men, the researchers said.

SURVEY How would you rate your exercise intensity? Low Moderate High Results  |  Disclaimer

"Conventional wisdom says that exercising for 30 minutes at a moderate exercise intensity is more effective in reducing anxiety than either a low or high intensity dose," said Richard Cox, professor of educational and counseling psychology and leader of the study. "This conclusion, however, is deceptively simple because reductions in anxiety are not always observed immediately following a high-intensity bout of exercise."

The study included women ages 18 to 20 and 35 to 45 whose anxiety levels were measured. Then the women either did not exercise or exercised at a moderate or high-intensity level for 33 minutes. After the session, Cox measured their anxiety levels at 5, 30, 60 and 90 minutes after they exercised.

Although all three exercise conditions showed a decline in anxiety over time, Cox found the high-intensity level experienced the sharpest decline, but the decline didn't emerge until a half-hour or later after the women exercised, Cox said.

Results also showed that when the iron status of the women was taken into consideration, the beneficial effect of high-intensity exercise was greater for the older women.

Cox believes this study, which is scheduled for publication in the Research Quarterly for Exercise and Sport, will prove beneficial to medical practitioners in the fight against heart disease.