Most people know it’s important to be physically fit, but a lot of us aren’t sure how to achieve that goal. Research has shown that regular physical activity can help prevent dementia, heart attacks, strokes, Type 2 diabetes and certain cancers, such as those of the breast and colon. The American College of Sports Medicine recently released evidence-based recommendations about the quality and quantity of exercise. Here are some do’s and don’ts based on those guidelines.

Do lift weights. In fact, if time is limited, shorten your aerobic activity to make time for weightlifting, suggests Carol Ewing Garber, chairwoman of the ACSM committee that wrote the new recommendations. Strength training is critical for older adults to help prevent age-related bone and muscle loss, both of which can lead to falls and serious injuries.

Don’t be a weekend warrior. Research suggests that it’s less effective for adults with cardiovascular risk factors to do most of their physical activity on Saturday or Sunday. Instead, do shorter bouts of exercise throughout the week.

Do diversify your exercise. The ACSM recommends “functional fitness” activities such as Pilates, tai chi and yoga. These combine balance, stretching and muscle strengthening, and they can improve your agility and body control.

Don’t stay sedentary during your downtime. Try to find six or seven more hours a week to spend on your feet, and move around more throughout the day. And try to cut your evening screen time.

Do stretch after working out, not before. To obtain maximum benefit from flexibility training, your muscles need to be warm.

Don’t rely solely on step counts. While pedometers can be effective for promoting activity, step counts aren’t an accurate measure of exercise intensity or quality. Better to use a heart-rate monitor to track intensity, and aim for a set number of minutes rather than a certain number of steps.

Do watch your eating. “While exercise alone can cut your body fat and alter your body’s composition, it has a small impact on actual weight loss over the short term – as little as five pounds a year,” Garber says. And losing pounds if you’re overweight can enhance the health benefits of exercise.

Don’t get discouraged if you’re not that fit. “Even a little exercise is better than nothing,” Garber points out. Slowly build up your duration, then focus on increasing the intensity. Try to add one to five minutes every two to three weeks.

By the Numbers

Do your best to meet these minimum exercise requirements from the American College of Sports Medicine:

Aerobic training. 5 days a week of moderate-intensity exercise, 30-60 minutes a day, at least 150 minutes a week, or 3 days a week of vigorous-intensity exercise, 20-60 minutes a day, at least 75 minutes a week.

Resistance training. 2-3 days a week, 48 hours between sessions, 2-4 sets per exercise, 8-12 reps per set (10-15 for older adults just starting exercise), 2-3 minutes of rest between sets.

Flexibility training (stretching). 2-3 days a week, hold each stretch for 10-30 seconds, repeat each stretch 2-4 times.

Functional fitness (Pilates,
tai chi, yoga).
2-3 days a week, 20-30 minutes a day.

Copyright 2011. Consumers Union of United States Inc.