The daily hour
The Physical Activity Guidelines for Americans, published by the U.S. Department of Health and Human Services (HHS), set out how much activity people need at each age. For young people aged 6 to 17 the headline is simple: at least 60 minutes of moderate-to-vigorous physical activity every day. The CDC uses the same recommendation, and MedlinePlus, the National Library of Medicine's health site, puts it as most children needing at least an hour of physical activity a day.
That hour does not have to happen in one go. HHS notes that the second edition of the guidelines dropped an older idea that only blocks of ten minutes or more counted. Walking to school, a sports practice, a game at lunch and a strength session in the evening all add up.
Three kinds of activity
The guidelines split the daily hour into three kinds of activity. The CDC's summary for ages 6 to 17 describes each one.
| Kind | What it is | How often | Examples from the CDC and HHS |
|---|---|---|---|
| Aerobic | Anything that makes the heart beat faster for a while | Most of the daily hour, with vigorous activity on at least 3 days a week | Walking, running, active games |
| Muscle-strengthening | Activity that makes muscles work harder than usual | At least 3 days a week, as part of the daily hour | Climbing, push-ups, structured weightlifting for adolescents |
| Bone-strengthening | Activity with impact that loads the bones | At least 3 days a week, as part of the daily hour | Jumping, running, jumping rope, basketball |
Two things stand out. First, strength and bone work sit inside the daily hour, not on top of it. Second, one activity can count for more than one kind: a basketball game is aerobic and bone-strengthening at once.
How hard is moderate or vigorous?
The CDC offers a simple way to judge effort. On a scale where sitting still is 0 and the hardest effort possible is 10, moderate activity is around 5 or 6, and vigorous activity is around 7 or 8. During moderate activity the heart beats faster and breathing is clearly harder than at rest. Walking to school with friends is usually moderate; running and chasing in a game of tag is usually vigorous.
This scale is personal. The same jog can be moderate for one teen and vigorous for another, and that is fine. The guidelines care about the effort each person makes, not about matching anyone else.
Where strength training fits
Muscle-strengthening activity is the part of the guidelines that strength training covers. The CDC's guidance makes a useful distinction by age: younger children usually build strength through play, such as climbing or gymnastics, and do not usually need formal programmes like weightlifting. As children become adolescents, they may start structured weightlifting programmes, often alongside their sports team practice.
For a teen who already plays a sport, some strength work may already be happening in team training. For a teen who does not, body-weight exercises, climbing, or a supervised gym session can all meet the muscle-strengthening part of the guidelines. Lifting weights is one option, not a requirement.
How a session is built is the subject of the next guide. This site does not give routines, numbers of sets or weights, because those depend on the person and should be set by a qualified coach or instructor who can watch the teen move.
An example week
Worked example (illustrative only)
This is an invented example to show how the pieces can fit together. It describes no real person and is not a plan to copy.
A 15-year-old walks to and from school most days. Twice a week they have soccer practice after school, which includes running drills and some body-weight strength exercises led by the coach. On Saturday they play a match. On one other weekday they go to a supervised session at a community gym, where an instructor is teaching them basic movements. Most days they get an hour or more of activity; on at least three days there is vigorous running, and on at least three there is strength and jumping work. On the remaining days they rest or do lighter activity such as a walk or a bike ride.
The point of the example is that the guidelines can be met by ordinary routines. It does not take a special programme, and rest days with lighter activity are a normal part of the week.
Why it matters
HHS summarises the benefits for young people as better thinking, bone health, fitness and heart health, and a lower risk of depression. The CDC adds that some brain benefits appear soon after a session of moderate-to-vigorous activity, including better thinking in children aged 6 to 13. MedlinePlus lists benefits that teens may notice directly: feeling less stressed, feeling better about themselves, feeling more ready to learn, building healthy bones, muscles and joints, and sleeping better.
None of these benefits is about appearance. They are about how a body works and how a person feels, which is the focus of this site.
Starting from less
Many teens are not near an hour a day, and that is a normal starting point. HHS states that any amount of physical activity has some health benefits. Moving a bit more than last week counts.
For someone starting from little activity, the sensible order is to build general activity first, through walking, cycling or a sport they enjoy, and to add strength work gradually. NIAMS lists increasing the intensity of activity too quickly as a risk factor for injury, so a slow build is the safer route as well as the more sustainable one.
If a teen has a health condition, or if activity causes pain, dizziness or unusual breathlessness, that is a reason to talk to a doctor before going further. The guide on when to see a doctor covers this in more detail.