Short, sharp bouts of exercise good for the heart
Short bouts of exercise can be just as effective at protecting the heart as longer workouts, but getting the heart rate up is a key factor as light activity offers no cardiac benefit, two new studies show (Circulation 2000;102:975-80, 981-7).
Physical activity has long been associated with a decreased risk of coronary heart disease. It has been unclear, however, whether the duration of exercise episodes was important and whether accumulated shorter sessions were as predictive of decreased risk as longer sessions, provided that the same amount of energy was expended in each instance.
In the two new studies the researchers found that even with relatively small amounts of physical activity, with an energy expenditure of only 1000 kcal (4.18 MJ) a week, the risk of coronary heart disease decreased by a fifth compared with people who did not take that amount of activity. It did not matter whether the person