How Much Exercise Is Enough?

Exercise is a cornerstone of good health—but how much do you need?

First, let’s consider how exercise is defined. It’s the same as physical activity, or any movement that causes your body to work harder than usual. Experts divide exercise into two types: aerobic and muscle strengthening.

Aerobic exercise

This type of exercise works your heart and lungs. It can be of moderate intensity or vigorous. If you are new to exercise, start slowly and work your way up to a more vigorous level of activity. Examples of moderate exercise are brisk walking, water aerobics, and pushing a lawn mower. Vigorous exercise includes jogging or running, swimming laps, and playing singles tennis.

You can monitor the intensity of your workout by checking your heart rate. Your target heart rate—the level you want to aim for while exercising at a moderate intensity—is 50 to 75 percent of your maximum heart rate. Find your maximum heart rate by subtracting your age from 220. Multiply this result by 0.6 to find your target heart rate.

A 40-year-old woman, for instance, has a maximum heart rate of 180 (220 - 40). Her target heart rate for a moderate-intensity workout is 108 (180 x 0.6).

Muscle-strengthening exercise

The CDC says you can build muscles by lifting weights, working with resistance bands, doing pushups, or doing yoga. You can also build muscle by digging or shoveling in the garden.

Your strength-training workout should include all the major muscle groups: legs, hips, back, chest, abdomen, shoulders, and arms.

Adults

Adults between ages 18 and 64 should aim for a minimum of 2.5 hours a week of moderate-intensity exercise, or 1.25 hours a week of vigorous activity, the U.S. Department of Health and Human Services (HHS) says. You can also combine amounts of moderate- and vigorous-intensity activities.

You can break your exercise time into chunks. It’s best if you spread your exercise over most days of the week.

The HHS says that you gain even more health benefits by exercising longer—increasing the total to five hours a week of moderate-intensity exercise or 2.5 hours a week of vigorous exercise.

Strength training should be done at least two days a week.

Older adults

Adults older than age 65 should follow the adult guidelines above, if possible. The HHS says older adults who have chronic conditions that limit their activities should still be as physically active as they can. In particular, older adults at risk for falling should do exercises that focus on balance.

Children and teens

Children and teens, ages 6 to 17, should get a minimum of an hour of physical activity every day, the HHS says. Most of kids’ daily exercise should be aerobic, and at least three days a week, it should be vigorous. Children and teens should also participate in muscle- and bone-strengthening activities at least three days a week.

Get the lead out

You can build physical activity into sedentary situations:

• Desk jobs. Take the stairs, not the elevator. Walk to a coworker's office rather than phoning. Take a 10- to 30-minute walk during your lunch hour. Get up, stretch, and move at least once an hour.

• Autos. Walk instead of driving for short trips. When driving, park farther away from your destination instead of looking for the closest parking space. Wash the car yourself rather than using an automatic car wash.

• TV. Work out on a stationary bike or treadmill while you watch. Replace a half-hour of viewing each day with exercise or exercise while viewing a favorite program.

Burning calories

Calories burned in an hour by a 154-pound adult:

Activity	Calories burned
Basketball	440
Golf (no cart)	330
Running	590
Aerobics	480
Swimming	510
Walking (3.5 mph)	280
Walking (4.5 mph)	460
Bicycling (more than 10 mph)	590
Weightlifting (vigorous workout)	440
Weightlifting (light workout)	220