Exercise is widely recognized for its positive impact on health, with many studies linking physical activity to better heart function, lower diabetes risk, and improved mental health. However, Harvard researchers emphasize that not all types of exercise fit every individual, and sometimes the best approach depends on personal circumstances. Understanding the nuances of when and how to be active can help people maximize benefits without risking injury or burnout.

Although the benefits of exercise are well-documented, there is still confusion about what counts as effective physical activity and how much is truly necessary. This report sheds light on how exercise improves health, highlights reasons some people may avoid it, and offers practical tips to incorporate more movement into daily life.

Why you should exercise weekly — and when to be cautious

Harvard’s research confirms that physical activity prevents or delays many health problems. For instance, exercise strengthens the heart by improving its efficiency and enhancing arterial flexibility. It also boosts “good” HDL cholesterol and helps muscles respond better to insulin, reducing the risk of type 2 diabetes.

Beyond heart and metabolic health, physical activity appears to lower the risk of certain cancers such as breast and colon cancer, with evidence suggesting that moderate to vigorous activity for several hours a week is needed to impact cancer prevention meaningfully.

Mental health benefits are another crucial aspect. Exercise has been shown to reduce depression symptoms and slow cognitive decline in older adults. It can even improve brain function after dementia begins, acting similarly to antidepressant medications in brain changes.

That said, many people don’t meet recommended activity levels. About half of American adults fall short of the guideline recommending at least 30 minutes of moderate-intensity exercise—such as brisk walking—on most days. Around a quarter report no physical activity during free time at all. Genetics partly explain why some people are naturally less active, but environmental factors like neighborhood safety and cultural influences also play big roles.

Simple ways to move more every day

Harvard experts stress that any exercise is better than none, especially for those who are very sedentary. Alongside the usual advice to do at least 150 minutes of moderate activity weekly plus muscle-strengthening exercises twice a week, they recommend easy ways to add movement in daily routines:

Park farther away and walk more to your destination.
Walk to bus stops a little further or get off public transit early.
Stand during commutes instead of sitting, which improves balance and core strength.
Swing your arms while walking to increase your pace and calorie burn.
Combine social activities with movement, like walking and talking in a book group or playing with children.
Use stairs instead of elevators, taking care not to overdo it.
Choose manual tasks like hand-washing dishes, gardening, or using a push mower to get light workouts.
Dance at home or join classes to make exercise enjoyable and less routine.
Limit screen time by hiding remotes or walking to change TV channels.
Take short breaks to stand or walk during phone calls or work hours.

These small changes can make a significant difference over time and help overcome barriers to regular exercise.