Although many people view exercise as a way to lose weight, it plays a key role in the wellbeing of the body beyond weight loss. Research strongly supports its benefits across a range of physical and mental health conditions for people of all ages. However, busy lifestyles and an environment that induces sitting for most hours of the day (driving door to door, sitting at an office desk, relaxing in the evening in front of the television) have led to exercise being a low priority for most people.
The Centers for Disease Control and Prevention found that only 1 in 5 American adults are meeting physical activity guidelines. Inactivity increases the risk of early death, type 2 diabetes, heart disease, stroke, osteoporosis, depression, and some cancers. 
In November 2018, the U.S. Department of Health and Human Services released its second edition of the Physical Activity Guidelines for Americans to provide evidence-based recommendations for children and adults.  Included are new evidence about specific health benefits of exercise and updated guidelines for different age groups: ages 3-5, 6-17, adults, and older adults. Special conditions in adults are addressed such as pregnancy and postpartum, chronic diseases, and disabilities. The guidelines highlight the specific amounts of exercise needed for each age and condition and types of exercises.
- New guidelines for children ages 3 through 5 encourage physical activity throughout the day to enhance growth and development. Adult caregivers should encourage children to participate in active play for at least 3 hours each day.
- Guidelines for ages 6 through 17 have not changed: at least 1 hour a day of moderate-to-vigorous activity with a combination of aerobic (walking, running, or anything that increases the heart rate) and strength movements to build muscles and bones (climbing on playground equipment or rock climbing walls, playing basketball, and jumping rope). If 1 hour a day can be achieved, more specific goals may be created such as including 3 days a week of vigorous activity and 3 days a week of strengthening activities (within the 1 hour).
- Guidelines for adults are the same but with a new focus: The first edition of the Physical Activity Guidelines for Americans stated that 10-minute bouts of physical activity a few times a day counted toward meeting the guidelines. The second edition removed this requirement to encourage Americans to simply move more frequently throughout the day. The key messages are to move more and sit less, and some activity is better than none. This recommendation is based on new evidence showing a strong relationship between being highly sedentary and an increased risk of heart disease, high blood pressure, and deaths from all causes. All types of physical activity can help offset these risks.
- For increased health benefits, adults should engage in at least 150 to 300 minutes a week of moderate-intensity aerobic activity, like brisk walking or fast dancing. At least two days a week should include muscle-strengthening activities, such as lifting weights or bodyweight exercises like push-ups, lunges, and squats. Ideally these exercises are spread throughout the week instead of over one or two days; for example, exercising 45 minutes every other day at a moderate to vigorous intensity is more sustainable and safer for your body than exercising for 1 ½ hr on Saturday and Sunday.
- Exercising for more than 300 minutes a week can improve health even more.
- Guidelines for older adults are the same as adults but should also include balance training such as tai chi or yoga. To ensure safety, before starting a program they should be aware of their level of fitness and any health conditions that may require a modified level of physical activity. Discussing an exercise regimen with their doctor before beginning a program may be helpful. It is important to increase physical activity gradually over time, to “start low and go slow” with lower intensity activities and then gradually increasing how often and how long the activities are performed.
- Guidelines for women who are pregnant or in the postpartum period suggest aiming for 150 minutes a week (spaced throughout the week) of moderate-intensity aerobic activity. Women who engaged regularly in vigorous-intensity exercise before pregnancy can continue this higher intensity throughout pregnancy. However, they should communicate with their doctor about their physical activity regimen during pregnancy and postpartum.
- Guidelines for adults with chronic conditions and disabilities who are able to exercise are similar to the general guidelines for adults. However, they should first discuss with their doctor about the types and amounts of activity that would be appropriate with their specific abilities and conditions. If they cannot meet the minimum physical activity guidelines, they may engage in exercise based on their abilities, while avoiding being completely sedentary.
Specific health benefits
- New evidence shows that physical activity has immediate health benefits for reducing anxiety and blood pressure and improving sleep quality and insulin sensitivity (which lowers the risk of prediabetes and type 2 diabetes).
- New evidence shows that meeting the physical activity recommendations consistently over time can lead to the following long-term health benefits:
- In youth, it can help improve cognition, bone health, fitness, and heart-health and reduce the risk of depression.
- In adults, it helps prevent eight types of cancer (bladder, breast, colon, endometrium, esophagus, kidney, stomach, and lung); reduces the risk of dementia including Alzheimer’s disease; reduces the risk of heart disease, stroke, high blood pressure, type 2 diabetes, depression, and deaths from all causes; and improves bone health, physical function, and quality of life.
- In older adults, it lowers the risk of falls and injuries from falls.
- In pregnant women, it reduces the risk of postpartum depression.
- In all groups, it reduces the risk of excessive weight gain and helps people maintain a healthy weight.
- New evidence shows that physical activity can help to improve existing health conditions. For example, physical activity can decrease the pain caused by osteoarthritis, slow the progression of hypertension and type 2 diabetes, reduce the severity of symptoms with anxiety and depression, and improve cognition in those with dementia, multiple sclerosis, ADHD, and Parkinson’s disease.
- The Centers for Disease Control and Prevention. Facts about Physical Activity. https://www.cdc.gov/physicalactivity/data/facts.htm Accessed 11/12/2018.
- The U.S. Department of Health and Human Services. Executive Summary: Physical Activity Guidelines for Americans, 2nd https://health.gov/paguidelines/second-edition/pdf/PAG_ExecutiveSummary.pdf Accessed 11/12/2018.