INDIANAPOLIS — When it comes to physical activity, more is better. That's the consensus of the American College of Sports Medicine (ACSM) and the American Heart Association in its updated physical activity guidelines released in late August.

Healthy adults ages 18 to 65 need moderate-intensity aerobic physical activity for at least 30 minutes five days each week or vigorous-intensity aerobic physical activity for at least 20 minutes three days each week, according to the updated physical activity guidelines.

In addition, adults benefit from performing activities at least two days each week that maintain or increase muscular strength and endurance. The two groups recommend that eight to 10 exercises using the major muscle groups be performed on two non-consecutive days. To maximize strength development, a weight should be used that results in willful fatigue after eight to 12 repetitions of each exercise.

The preventive recommendation specifies how adults, by engaging in regular physical activity, can promote and maintain health and reduce risk of chronic disease and premature death.

The groups also released a companion recommendation for adults ages 65 and older and adults between the ages of 50 and 64 with chronic conditions or physical functional limitations.

The recommendations are an update and clarification of the 1995 recommendation from the Centers for Disease Control and Prevention and ACSM on the types and amounts of physical activity needed by healthy adults to improve and maintain health. The core recommendation remains fundamentally unchanged despite the fact that more than 10 years have passed since it was issued.