Exercise is an essential component of a healthy lifestyle. Exercise helps people maintain healthy weights, improves mood, reduces the risk for various health ailments, and much more. But how much exercise is necessary for optimal health? Research indicates that the answer to that question depends on the person and his or individual health goals.

According to David Bassett, Jr., PhD, a professor of exercise physiology at the University of Tennessee in Knoxville, having a clear set of exercise goals can help a person determine just how much exercise he or she needs, particularly if a person is exercising to control his or her weight or reduce his or her stress.

The U.S. Department of Health and Human Services recommends that most healthy adults get at least 150 minutes of moderate aerobic activity or 75 minutes of vigorous aerobic activity, or a combination thereof, every week. Try to engage in strength training for all major muscle groups at least two times per week. The Mayo Clinic says a general goal for most people is to aim for at least 30 minutes of moderate physical activity every day.

Health experts say that this exercise needn’t all occur at once, either. If a 30-minute walk is not possible, split that up into a few 10-minute walks throughout the day. Any activity is better than doing nothing at all.

For those with specific fitness goals, it could be wise to speak with a trainer or a doctor about which types of exercises (and durations) are effective. Physicians may be able to map out a fitness plan that works.