Where the numbers come from
When public health agencies in the United States talk about how much physical activity people need, they are almost always describing one document: the Physical Activity Guidelines for Americans, published by the U.S. Department of Health and Human Services (HHS). The current version is the second edition. HHS describes it as evidence-based guidance to help people keep or improve their health through physical activity, and it covers children, adults, older adults, pregnancy and the postpartum period, and adults with chronic health conditions or disabilities.
The Centers for Disease Control and Prevention (CDC), the National Heart, Lung, and Blood Institute and the HHS Move Your Way campaign all repeat the same core amounts in plainer language. This guide follows those summaries. It covers adults; the guide on activity for older adults covers what changes after 65.
Nothing here is specific to Pittsburgh, and that is the point. The guidelines are national, and they apply in the same way in every Pittsburgh neighborhood as anywhere else in the country. What differs from person to person is how you get there, which the later guides look at.
The weekly amounts for adults
The guidelines describe two kinds of activity that adults need every week: aerobic activity, which gets you breathing harder and your heart beating faster, and muscle-strengthening activity. The CDC's overview for adults puts the aerobic part as:
- At least 150 minutes a week of moderate-intensity activity, such as brisk walking, or
- 75 minutes a week of vigorous-intensity activity, such as jogging or running, or
- an equivalent mix of the two.
On top of the aerobic part, adults need muscle-strengthening activity on at least 2 days a week that works all the major muscle groups: legs, hips, back, abdomen, chest, shoulders and arms. The guide on strength twice a week explains what counts.
HHS's own summary of the second edition gives the aerobic target as a range rather than a single figure: 150 to 300 minutes a week of moderate-intensity activity. The National Heart, Lung, and Blood Institute gives the matching vigorous range as 75 to 150 minutes. The lower number is the amount linked with substantial health benefits; the CDC adds that going beyond 150 minutes of moderate activity, or 75 of vigorous, brings even more benefit.
| Kind of activity | Weekly amount | Examples the agencies give |
|---|---|---|
| Moderate aerobic | 150 to 300 minutes | Brisk walking, fast dancing, water aerobics, riding a bike on level ground |
| Vigorous aerobic (instead) | 75 to 150 minutes | Jogging or running, swimming laps, riding a bike fast or on hills |
| Muscle-strengthening | At least 2 days | Lifting weights, resistance bands, push-ups, heavy gardening such as digging |
One hundred and fifty minutes sounds like a lot. The CDC's own way of putting it is that it could be 30 minutes a day on 5 days a week, and that you do not have to do it all at once: you can spread it across the week and break it into smaller pieces. The second edition of the guidelines dropped an older rule that only bouts of 10 minutes or longer counted. Shorter stretches of moderate or vigorous movement now count toward the total too.
Moderate and vigorous, explained
Intensity is how hard your body is working during aerobic activity. The guidelines care about two levels.
Moderate intensity means you are working hard enough to breathe harder and raise your heart rate. The CDC describes it as the point where you can still talk but could not sing the words to a song. Brisk walking is the standard example.
Vigorous intensity means you are breathing hard and fast, and your heart rate is clearly higher than at moderate effort. At this level you cannot say more than a few words without pausing for breath. Jogging and running are the usual examples.
The same activity can be moderate for one person and vigorous for another. The CDC is explicit about this: walking may feel moderate to you and vigorous to someone else, depending on fitness, comfort and health. What matters is the effort for you, not the name of the activity.
Three ways to check your effort
The CDC page on measuring intensity describes three practical tools. None needs any equipment.
- The talk test. If you can talk but not sing, you are probably at a moderate level. If you cannot say more than a few words without stopping for breath, you are at a vigorous level.
- A 0 to 10 effort scale. Think of sitting still as 0 and your hardest possible effort as 10. Moderate activity sits at about 5 or 6. Vigorous activity starts at about 7 or 8.
- METs, for the curious. Researchers measure absolute intensity in metabolic equivalents, or METs, where 1 MET is the energy you use sitting quietly. Activities at 3 to 5.9 METs count as moderate and those at 6 or more as vigorous. This is useful for comparing published lists of activities, but the first two tools are easier to use while you are moving.
Worked example
This is an invented example, not a real person. Someone walks to a bus stop at an easy pace and can chat comfortably the whole way. On the 0 to 10 scale that feels like a 3. On the way home they pick up the pace up a hill until they can still talk but would not want to sing. That stretch feels like a 5 or 6, so it counts as moderate. Only the second part fits the guidelines' description of moderate activity, although the guidelines also say that moving more and sitting less is worthwhile in itself.
Mixing moderate and vigorous
You do not have to pick one kind of intensity. The CDC gives a rule of thumb: 1 minute of vigorous activity is about the same as 2 minutes of moderate activity. That is why 75 minutes of vigorous activity is treated as equivalent to 150 minutes of moderate activity.
The CDC's sample weekly plans show how this can look in practice. One plan is five 30-minute brisk walks plus two days of weight training. Another replaces the walks with 25-minute jogs on three days. A mixed week combines a few 30-minute brisk walks with a couple of 15-minute jogs. Each adds up to the equivalent of 150 minutes of moderate activity, with two days of strength work alongside.
If you want to move toward more vigorous activity, the CDC suggests doing it gradually, replacing some moderate activity such as brisk walking with something harder such as jogging, and telling your doctor first if you have a history of chronic disease.
Move more, sit less
HHS lists "move more and sit less" as the first key guideline for adults in the second edition. Its summary explains why: evidence links more sitting with a higher risk of heart disease, high blood pressure and death from any cause, and physical activity, especially at moderate to vigorous levels, can help offset those risks.
Just as important, HHS says that any amount of physical activity has some health benefits. Adults who sit less and do any amount of moderate or vigorous activity gain something, even if they are a long way from 150 minutes. The guidelines are a target to work toward, not a pass or fail line. The next guide, starting from zero, is about that working-toward part.
How to read the numbers
A few points help keep the numbers in proportion.
- They are population guidelines. They describe amounts linked with health benefits across large groups of people. They are not a personal prescription, and they do not replace advice from someone who knows your health.
- Benefits start early. HHS's summary says some benefits are immediate: physical activity can reduce anxiety and blood pressure and improve sleep quality soon after a session. Longer-term benefits build when activity is kept up over time.
- They are not a weight-loss plan. The CDC notes that people vary a lot in how much activity they need to manage their weight, and that eating patterns matter as much as activity. This site does not give weight-loss advice.
- Conditions and disabilities change the details, not the principle. The CDC says adults with chronic conditions or disabilities who are able to should aim for the same amounts, and should talk with a health care professional about the types and amounts that suit them.
In short: aim for at least 150 minutes of moderate activity a week, or the vigorous equivalent, plus strength work on two days, and count every bit of movement along the way.