Despite these difficulties, there is some evidence that exercise reduces stress. Adrenaline, a hormone released during stress, increases heart rate, blood pressure and blood glucose. Exercise reduces the amount of adrenaline released during stress. Exercise also reduces muscular tension, and for some people exercising in a group may provide social support. Many of the beneficial effects of exercise on risk factors come from its effects on weight loss.
Exercise combined with diet is more effective in reducing weight than diet alone.
Those who lose weight from exercise and diet tend to gain muscle and lose fat. To be most effective in weight loss, exercise should last at least 45 minutes. Even without its effects on other risk factors, inactivity is a risk factor in its own right. The greatest benefit is found in those who change from being inactive to being slightly active. Walking for 30 minutes 5 times a week is sufficient.