Moderate physical activity is usually recommended for people from 18 to 64 years of age. Fitness routines come with a number of guidelines and recommendations that often vary depending on age, gender, size, and other factors. Knowing the basics about how long you should exercise for and how many days per week can help you feel more confident in your own fitness routine. In general, moderate-level physical activity should be a part of your daily routine to promote healthy aging and development. However, some people may need to adjust their routine depending on certain health concerns or other extenuating circumstances.