Even a little exercise has health benefits: study - Reuters

new study shows that even low levels of weekly exercise - below currently recommended levels -- has major health benefits. In the study, 30 minutes of brisk walking three days per week was enough to drive down blood pressure and improve overall fitness in a group of healthy sedentary adults.

For optimum health, adults are currently recommended to engage in 30 minutes of moderately strenuous exercise on at least five days of the week. But few people achieve this level of weekly activity, often citing lack of time as the reason.