It is no real news that exercise helps reduce stress. I am a living proof of that fact. Scientists are continuing to study the relationship between stress reduction and exercise.
In a recent study participants had their blood drawn before and after completing two really frustrating tasks. The stress induced heart damaging chemicals spiked 5 times higher in the least fit subjects. The fit subjects were folks that jogged or cycled twice a week as well as walked for 30 - 40 minutes twice a week. The fitter people were generally leaner, minimizing their body fat. And it is fat that produces inflammatory chemicals that lead to heart disease.
The researchers conducting this study feel that two intense workouts a week should be enough to beat the stress. I just want to reiterate that was just 2 workouts a week. If you tend to fly off the handle, this could be the prescription for you.