Jogging may be best in small quantities, according to a recent study.

Researchers found that jogging for1 to 2.4 hours per week was associated with the lowest mortality and the optimal frequency of jogging was no more than three times per week.

"It is important to emphasize that the pace of the slow joggers corresponds to vigorous exercise and strenuous jogging corresponds to very vigorous exercise," said Peter Schnohr, a researcher from the Copenhagen City Heart Study, Frederiksberg Hospital in Copenhagen, Denmark. "When performed for decades, this activity level could pose health risks, especially to the cardiovascular system."

For the study, researchers looked at more than 5,000 healthy participants in the Copenhagen City Heart Study and questioned them about their activity. They identified and tracked 1,098 healthy joggers and 413 healthy but sedentary non-joggers for 12 years.

The study, which tracked hours of jogging, frequency, and the individual's perception of pace, found that over the 12-year study strenuous joggers were as likely to die as sedentary non-joggers, while light joggers had the lowest rates of death.

Overall, significantly lower mortality rates were found in those with a slow or moderate jogging pace, while the fast-paced joggers had almost the same mortality risk as the sedentary non-joggers.

These findings show similar results to past studies where researchers have found that more than moderate exercise may cause more harm than good.

"The U-shaped association between jogging and mortality suggests there may be an upper limit for exercise dosing that is optimal for health benefits," Schnohr said. "If your goal is to decrease risk of death and improve life expectancy, jogging a few times a week at a moderate pace is a good strategy. Anything more is not just unnecessary, it may be harmful."

The findings are detailed in the Journal of the American College of Cardiology.