Where the Guidelines Come From
The Physical Activity Guidelines for Americans are published by the U.S. Department of Health and Human Services (HHS). The current version — the second edition — was released in 2018 and is informed by a comprehensive review of thousands of peer-reviewed studies conducted by the Physical Activity Guidelines Advisory Committee. These are not arbitrary targets; they reflect a synthesis of evidence on how physical activity relates to a wide range of health outcomes, including cardiovascular disease, type 2 diabetes, several cancers, mental health, and all-cause mortality.
The guidelines apply to healthy adults aged 18–64, with separate guidance for older adults, children, pregnant and postpartum women, and adults with chronic conditions. Understanding which population a guideline addresses matters — applying a general adult target to someone in a high-risk group without professional input is not what the guidelines intend.
These Guidelines Are Not Medical Prescriptions
The Physical Activity Guidelines for Americans represent population-level public health targets, not individualized medical advice. Adults with chronic conditions, recent injuries, pregnancy, or other health concerns should consult a qualified healthcare professional before significantly changing their activity level. The guidelines themselves include specific chapters for these groups.
The Core Numbers — and What They Actually Mean
The most widely cited targets are:
- 150–300 minutes per week of moderate-intensity aerobic activity, or
- 75–150 minutes per week of vigorous-intensity aerobic activity, or
- An equivalent combination of both.
On top of aerobic activity, the guidelines call for muscle-strengthening activities — targeting all major muscle groups — on at least two days per week.
| Recommended weekly aerobic activity (moderate) | 150–300 minutes (U.S. Department of Health and Human Services, Physical Activity Guidelines for Americans, 2nd edition) |
| Recommended weekly aerobic activity (vigorous) | 75–150 minutes (U.S. Department of Health and Human Services, Physical Activity Guidelines for Americans, 2nd edition) |
| Muscle-strengthening sessions per week | At least 2 (U.S. Department of Health and Human Services, Physical Activity Guidelines for Americans, 2nd edition) |
| Minimum bout length required | None — all movement counts (Updated in the 2018 guidelines revision) |
| Adults meeting both aerobic and strength guidelines | Approximately 24% (CDC National Center for Health Statistics, 2022 data) |
| Additional benefit zone | 300+ min/week moderate aerobic (U.S. Department of Health and Human Services, Physical Activity Guidelines for Americans, 2nd edition) |
These numbers define a range, not a single mandatory threshold. Doing more than 150 minutes of moderate activity is associated with additional health benefits, up to roughly 300 minutes per week. Beyond that, incremental gains continue but at a diminishing rate. To understand what counts as moderate versus vigorous, see our guide to moderate-intensity exercise for a practical breakdown.
Key Things the Guidelines Don't Require
A significant update in the 2018 revision removed the previous requirement that aerobic activity occur in bouts of at least 10 minutes. All movement now counts — a three-minute walk to a meeting, climbing stairs, or a brief gardening session all accumulate toward weekly totals. This change was driven by evidence showing that shorter episodes of activity confer meaningful benefits.
The guidelines also do not specify:
- A particular time of day to exercise
- A specific type of aerobic activity
- Gym membership or equipment
- A minimum fitness level to start
Walking, for instance, is a fully guideline-compliant form of aerobic activity for most adults, and one of the most studied. The guidelines are deliberately mode-neutral to maximize accessibility.
Aerobic activity
Rhythmic, sustained physical movement that raises your heart rate and breathing. It includes activities like walking, cycling, swimming, and dancing, and is the foundation of most physical activity recommendations.
Moderate intensity
An effort level at which you can talk but not sing comfortably. It noticeably raises your heart rate without making conversation impossible.
Vigorous intensity
An effort level at which sustained conversation becomes difficult. Running, fast cycling, and aerobic dance typically fall into this category.
MET (Metabolic Equivalent of Task)
A unit researchers use to express the energy cost of physical activities relative to sitting at rest. Moderate-intensity activities are generally defined as 3–6 METs; vigorous activities exceed 6 METs.
Muscle-strengthening activity
Exercise that works major muscle groups against resistance — including weight training, bodyweight exercises, resistance bands, and heavy gardening. Guidelines recommend this at least two days per week.
Sedentary behavior
Any waking activity done while sitting or reclining with very low energy expenditure — distinct from simply not exercising. Prolonged unbroken sitting carries its own health considerations.
Getting Started and Staying Consistent
For adults who are currently inactive, the guidelines note that some activity is better than none. Even amounts below the recommended targets are associated with reduced health risk compared to no activity at all. This framing matters: the guidelines are not designed to discourage those who can't immediately hit 150 minutes per week.
Research consistently shows that consistency over time matters more than peak effort in any single session. Building sustainable habits — rather than dramatically overhauling your routine — tends to produce more durable results. Common misconceptions about exercise, including the idea that workouts must be intense to be worthwhile, are addressed in our breakdown of persistent exercise myths.
It's also worth distinguishing between planned exercise and overall daily movement. Extended periods of sitting carry their own considerations — and reducing unbroken sedentary time has value independent of meeting weekly aerobic targets. See our piece on what sedentary behavior actually means for a clearer picture of the distinction.
This article is for general informational and educational purposes only and is not a substitute for professional medical advice. Consult a qualified healthcare provider before making significant changes to your physical activity routine, especially if you have an existing health condition.
The content on this site is provided for informational purposes only and should not be considered a substitute for professional advice. While we strive to provide accurate and up-to-date information, we make no guarantees regarding its completeness or accuracy. Always consult a qualified professional for advice specific to your circumstances before making any decisions.