The recommended amount of physical activity for cardiac health by the American Heart Association is 150 minutes of moderate-intensity physical activity per week (approximately 30 min a day, 5 days a week). This has been the recommendation for many years until recently.
According to new research published in the flagship journal of the American Heart Association "Circulation", though 150 minutes does offer cardiovascular protection, the maximal benefits from exercise accrue when that number is doubled to 300 minutes or better quadrupled to 600 minutes of moderate-intensity physical activity per week. For easy quantification the AHA has graded the intensity of exercise by the "talk test". Moderate exercise / activity is defined as the level of intensity that allows a person to talk but not sing during the exercise. Vigorous physical activity is defined as that that intensity of physical activity during which the person cannot speak more than a few words continuously. Athletes combine moderate and vigorous levels of physical activity alternatively (also called high intensity interval training - HIIT) for further enhancing the cardioprotective effects.
It's becoming clear now - the more active you are the more benefits you'll reap.
