How Much Exercise Do You Need Each Week?

Adults should aim for 150 to 300 minutes of moderate aerobic activity a week, or 75 to 150 minutes of vigorous activity, or a mix, plus muscle-strengthening activity on two or more days. That’s what both the World Health Organization (WHO) and the US Physical Activity Guidelines recommend. If that sounds like a lot, the guidelines are just as clear on the other point: any amount is better than none.

This article is general information, not medical advice.

The Guidelines

The WHO’s 2020 guidelines and the second edition of the Physical Activity Guidelines for Americans (Piercy and colleagues, 2018) agree for adults:

• Aerobic activity: at least 150 to 300 minutes a week at moderate intensity, or 75 to 150 minutes at vigorous intensity, or an equivalent mix. A vigorous minute counts as about two moderate ones.
• Muscle strengthening: activities that work all major muscle groups on two or more days a week.
• Older adults: add balance and functional training, such as on three or more days a week, to help prevent falls.
• Less sitting: replace time sitting with activity of any intensity, even light.

Going beyond 300 minutes brings additional benefits, and the US guidelines dropped the old rule that activity only counted in bouts of 10 minutes or more: every minute counts.

Moderate or Vigorous?

• Moderate: you can talk but not sing, such as brisk walking, easy cycling, or doubles tennis.
• Vigorous: you can say only a few words without pausing for breath, such as running, fast cycling, or swimming laps.

By heart rate, moderate is roughly 64% to 76% of your maximum and vigorous 77% to 95%; see How to Estimate Your Maximum Heart Rate and Training Zones.

What a Watch’s Exercise Minutes Count

Apple Watch’s green Exercise ring counts minutes of brisk activity, judged from your movement and heart rate, whether or not you started a workout. Other devices use their own definitions, often called active or intensity minutes. These figures are useful for a daily habit, but they’re estimates by each maker’s rules: a slow walk may not count, and a bike ride with a still wrist may count less than it should. They aren’t the same as the minutes of workouts you log yourself.

Building Up to It

• Count the week, not the day. 150 minutes can be five sessions of 30, three of 50, or many shorter ones.
• Start where you are. Ten more minutes of walking a day is 70 a week, nearly half the target.
• Mix in strength. Two short sessions a week of squats, push-ups, and carrying count toward the second goal.

Following It in Kaizora

Kaizora keeps these apart: Exercise Time is the duration of the workouts and activities you record (from Apple Health’s workouts or logged with Log), Exercise Sessions counts them, and Apple Exercise Time is Apple Watch’s own Exercise ring minutes, a metric of its own since it’s Apple’s definition. All are summed, so a week’s value is its total. A habit such as “at least 150 minutes of exercise in any 7 days” checks the guideline every day, so a new week never resets it; see Habits. Activity’s Overview charts your time on each type of activity by day.

The Short Version

• 150 to 300 minutes of moderate, or 75 to 150 of vigorous, activity a week, plus strength twice a week.
• Every minute counts, and more than 300 minutes brings more benefit.
• A watch’s exercise minutes follow its maker’s rules; use one measure for your habit.

Sources

• World Health Organization, WHO guidelines on physical activity and sedentary behaviour (2020).
• Piercy KL et al., “The Physical Activity Guidelines for Americans,” JAMA 320, no. 19 (2018): 2020. doi:10.1001/jama.2018.14854
• US Office of Disease Prevention and Health Promotion, Physical Activity Guidelines for Americans.
• Apple, Track daily activity with Apple Watch.