How Much Exercise Do Adults Need? The Federal Numbers, Explained

Ask ten people how much exercise you need and you will get ten answers, most of them from someone selling something. There is an official answer. The U.S. Department of Health and Human Services publishes the Physical Activity Guidelines for Americans, now in its second edition, and the CDC repeats the same numbers. Here is what they say, and what they do not.

The key guidelines for adults

Guideline	What it means
Move more and sit less	Some activity is better than none; any amount of moderate-to-vigorous activity brings some benefit
150 to 300 minutes a week of moderate activity	2 hours 30 minutes to 5 hours, for example brisk walking
or 75 to 150 minutes of vigorous activity	1 hour 15 minutes to 2 hours 30 minutes, for example jogging
or an equivalent mix	Each vigorous minute counts roughly as two moderate ones, as the CDC’s examples show
Muscle-strengthening on 2 or more days	Moderate or greater intensity, all major muscle groups
Beyond 300 minutes	Additional health benefits

The guidelines add that aerobic activity should preferably be spread throughout the week. The CDC’s shorthand is 150 minutes of moderate activity and 2 days of muscle-strengthening each week, which is the low end of the range and the place to aim first.

Moderate versus vigorous

The guidelines describe intensity in two ways. By energy use, moderate activity includes walking briskly at 2.5 to 4 mph, playing doubles tennis or raking the yard. Vigorous activity includes jogging, running, carrying heavy groceries or other loads upstairs, shoveling snow or a strenuous fitness class. By effort, on a scale where sitting is 0 and your maximum is 10, moderate is a 5 or 6 and vigorous starts at 7 or 8.

The CDC’s second example plan shows the trade: three 25-minute jogs a week add up to 75 minutes of vigorous activity, which meets the target on their own. Its third example mixes 30-minute brisk walks with 15-minute jogs.

The parts most people miss

Every bout counts

The 2008 guidelines said activity had to last at least 10 minutes to count. The 2018 edition removed that rule after its advisory committee concluded that bouts of any length contribute to the benefits. The guidelines’ own example is climbing a few flights of stairs. That change is the basis for every short routine on this site.

The first steps matter most

The guidelines state that even small increases in moderate activity provide benefits and that there is no threshold that must be exceeded before benefits begin. For any given increase, the relative gain is greater for people who are not yet active than for people who already meet the guidelines. If you do nothing now, a little is a lot.

Sitting is its own issue

More time spent sitting is linked in the guidelines to higher risk of death from all causes, cardiovascular disease, type 2 diabetes and some cancers. For inactive people, a good first step is to replace sitting with light-intensity activity, such as slow walking or light household chores. See Standing and Moving During the Workday.

What the minutes buy you

The CDC says physical activity helps you immediately feel better, function better and sleep better. The guidelines list effects that appear on the same day as a single session of moderate-to-vigorous activity: lower blood pressure, better insulin sensitivity, better sleep, fewer anxiety symptoms and improvements in some aspects of thinking. With regular activity, the guidelines report people fall asleep faster, sleep more efficiently, get more deep sleep and feel less sleepy in the daytime.

Longer-term benefits listed by the CDC include lower risk of heart disease and stroke, type 2 diabetes and at least eight types of cancer, stronger bones and muscles, and a lower risk of falls for older adults. The guidelines define physical fitness in words that fit this site well: the ability to carry out daily tasks with vigor and alertness, without undue fatigue, and with ample energy to enjoy leisure-time pursuits.

Older adults

The weekly targets are the same for adults 65 and older, with one addition. The CDC says older adults need aerobic, muscle-strengthening and balance activities, and the National Institute on Aging suggests about three sessions of balance exercises a week. NIA points out that activities such as dancing, yoga, tai chi and gardening often combine several types at once.

Getting there safely

• Start low and go slow: increase how often and how long you are active gradually, as the guidelines advise inactive people.
• Choose activities that suit your current fitness level and goals.
• If you have a chronic condition such as heart disease, arthritis or diabetes, the CDC recommends asking your doctor about the types and amounts of activity that are right for you.
• Talk to your doctor before vigorous activity if you have been inactive, have a disability or have overweight, the CDC adds.

For the strength side of the guideline without a gym, see Strength Training With No Gym: Two Days a Week at Home.