Just take a guess---how long do you think exercise improves your mood?

Is it 2, 4, 8, 10, or perhaps even 12 hours after you workout?

If you guessed 12 hours, you' d be correct.

A new study "at the University of Vermont had 24 college students ride an exercise bike for 20 minutes at a moderate intensity. Another 24 people did no exercise during the same time period," according to USA Today.

Afterward everyone filled out a questionnaire that addressed such mood related questions as tension anger, vigor, fatigue, confusion and depression.

And you can probably guess the rest.

USA Today goes on to report that, "The researchers found that people in the exercise group experienced a significant improvement in mood immediately after the exercise. They also had improved moods after two, four, eight and 12 hours compared with the people who didn' t exercise, says Jeremy Sibold, an assistant professor in the university' s Department of Rehabilitation and Movement Science."

"There are other studies that show there is acute improvement in mood after exercise, but we found those improvements are more durable than we thought," Sibold says.

The bad news is that after 24 hours there was no difference in mood between the two test groups.

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