Count Calories, not Minutes, to Stay Healthy
Are you confused by the constantly changing guidelines for how long you need to exercise to maintain good health? In an effort to try to reconcile the debate, the July 2004 issue of the Harvard Heart Letter suggests concentrating on the number of calories burned instead of time.
Most experts agree burning calories is the means to maintaining a healthy weight. According to a Harvard study of 17,000 people, burning an extra 700 to 2,000 calories a week by walking, playing sports, or doing some other form of exercise increases life span. The health benefits seem to level off at about 2,000 calories a week, which is equivalent to walking three miles a day.
Because the amount of calories burned during a workout depends on a person’s weight and the intensity and duration of the activity, the Harvard Heart Letter suggests finding personal benchmarks based on your weight and lifestyle. For example, exercise standards for a 155-pound person say walking for 30 minutes at four miles-per-hour burns 150 calories. Heavy cleaning for 45 minutes burns 250 calories, and an hour of singles tennis burns 300 calories.
The report explains that intensity makes a difference. The authors say for an activity to benefit your cardiovascular system, the intensity must be enough to increase heart rate and speed up your breathing. Depending on your free time and preferences, brief sessions of intense activity can burn the same number of calories as longer or more frequent sessions of a less intense activity.
For an inexpensive and accessible option, the Harvard Heart Letter suggests walking. If you are working out in a club, they say a treadmill will burn the most calories. The authors also say, as a bonus, walking is a weight-bearing exercise that can prevent osteoporosis.
SOURCE: Harvard Heart Letter, July 2004