The American College of Sports Medicine (ACSM) and the American Heart Association (AHA) published a guidance for exercise for good health in general people, as below-
One should engage in continuous exercise or moderate-intensity aerobic exercise (fatigue until unable to sing a song but can carry on a conversation) for a minimum of 30 minutes/day at least 5 days/week or vigorous-intensity aerobic exercise for a minimum of 20 minutes/day at least 3 days/week.
One should combine continuous exercise with strength training exercise, by exercising twice a week on non-consecutive days. Each day one should do Eight to ten sets, each set of 8-12 repetitions of strength training exercise and the target muscle groups must be used in each set with the heaviest resistance/weight that allows 10 repetitions, resulting in extreme fatigue. Examples of strength training exercise include weight lifting, walking up and down stairs and doing body weight exercise such as sit ups and push-ups.
Continuous exercise or aerobic exercise can be done as short bouts (lasting at least 10 minutes). of moderate-intensity exercise (fatigue until not able to sing a song).
Above exercises are even done for minimum amount or time provide great health benefits (dose-response). Therefore, people who wish to improve their personal fitness and reduce their risk for premature chronic health conditions and prevent weight gain should exceed these minimum recommended amounts of exercise.
Elderly people should do the balance exercise for a minimum of 10 minutes/day twice a week and have a daily physical activity plan of moving enough and doing all types of exercises they can tolerate. In the case of elderly people with sedentary behavior, an exercise plan should be made where activity gradually increases over several months. Elderly people should be warned to always observe and assess themselves during exercise.