The magic numbers are 20 and 20; 20 minutes of aerobic activity and 20 minutes of strength training, and there are a couple ways to meet the goal.


With the New Year upon us, resolve to get 20 minutes of aerobic activity three days a week and 20 minutes of strength training three days a week. 

Not sure how? You can do it a couple of ways. Lift and do cardio in the same day for 40 minutes and you only exercise three days a week. Or split your sessions into 20-minute bouts six days a week. Your bones and heart will thank you.

If you exercise at home, it may be more convenient to do 20-minute activity sessions six days a week. If you train at a gym, it may be more practical to perform 40-minutes of activity three days a week. (It doesn’t matter which you do first, cardio or weights, just as long as you do them.)

Feel the burn –   When you lift weights, take about 30 to 90 seconds to complete 8 to 15 reps using a challenging weight.

Heart of the matter –  For aerobic activity, your heart rate should be  65 to 85 percent of maximum heart rate, with a recommendation of about 75 percent of maximum heart rate. For example, if your maximum heart rate is 200 beats per minute, your cardiovascular training heart rate should be in the neighborhood of 150 beats per minute. (The standard means for estimating your maximum heart rate is to subtract your age from 220.)  A good exertion gauge is to be able to talk in short sentences while exercising.

Lean machines –  People who are out of shape, have poor balance or orthopedic problems may do better with weight-supported fitness machines such as recumbent cycles, upright cycles or rowing machines. The next progression may be to exercise equipment that does not require landing force/shock absorption, such as elliptical trainers or step machines. Treadmill walking has limited landing force/shock absorption because one foot is always on the track. However, treadmill running produces more musculoskeletal stress. Rope jumping also requires higher levels of landing force/shock absorption, and should be reserved for relatively fit individuals.

Fire up your fitness – Pump up the volume on your workout by mixing endurance activities like 10 minutes of biking and 10 minutes of jogging.  By doing complementary aerobic activities during the same workout, your cardiovascular system benefits by a higher overall training intensity. A bonus: Reduces the risk of overuse/imbalance injuries from relatively long periods of repetitive movements.

Interval training varies the exercise intensity throughout the workout. Divide a 20-minute walk on the treadmill into five four-minute segments – walk, jog, walk uphill, etc. You’ll burn more calories. 

Wayne L. Westcott, Ph.D., is senior fitness executive for the South Shore YMCA in Quincy, Mass., and adjunct professor of exercise science at Quincy College. He is author of 22 books on strength training and physical fitness, including his latest release ``Get Stronger, Feel Younger'' by Rodale Press.