Muscle-strengthening activities provide additional benefits not found with aerobic activity. The benefits of muscle-strengthening activity include increased bone strength and muscular fitness. Muscle-strengthening activities can also help maintain muscle mass during a program of weight loss.

Muscle-strengthening activities make muscles do more work than they are accustomed to doing. That is, they overload the muscles. Resistance training, including weight training, is a familiar example of muscle- strengthening activity. Other examples include working with resistance bands, doing calisthenics that use body weight for resistance (such as push- ups, pull-ups, and sit-ups), carrying heavy loads, and heavy gardening (such as digging or hoeing).

These examples show how it's possible to meet the Guidelines by doing moderate-intensity or vigorous-intensity activity or a combination of both. Physical activity at this level provides substantial health benefits.

Ways to get the equivalent of 150 minutes (2 hours and 30 minutes) of moderate-intensity aerobic physical activity a week plus muscle- strengthening activities: Thirty minutes of brisk walking (moderate intensity) on 5 days, exercising with resistance bands (muscle strengthening) on 2 days; Twenty-five minutes of running (vigorous intensity) on 3 days, lifting weights on 2 days (muscle strengthening)...

Adults who are physically active are healthier and less likely to develop many chronic diseases than adults who are inactive. They also have better fitness, including a healthier body size and composition. These benefits are gained by men and women and people of all races and ethnicities who have been studied. Adults gain most of these health benefits when they do the equivalent of at least 150 minutes of moderate intensity aerobic physical activity (2 hours and 30 minutes) each week. Adults gain additional and more extensive health and fitness benefits with even more physical activity.

Muscle-strengthening activities also provide health benefits and are an important part of an adult's overall physical activity plan. This article provides guidance for most men and women aged 18 to 64 years, and focuses on physical activity beyond baseline activity (the usual light or sedentary activities of daily living). The guidelines for adults focus on two types of activity: aerobic and muscle- strengthening.

Flexibility is an important part of physical fitness. Some types of physical activity, such as dancing, require more flexibility than others. Stretching exercises are effective in increasing flexibility, and thereby can allow people to more easily do activities that require greater flexibility.