Physical activity need not be strenuous to be of benefit. Indeed, all of us have many opportunities to become more active in our daily routine. Climb the stairs instead of taking the elevator. Walk to the store instead of driving. Use a push lawn mower instead of a power lawn mower. It's never too late to become active. If you are already active, keep at it. If you are not, here are a few tips for getting started:

Get a physical. Before starting, ask your physician about any limitations on your activity.

Pick the right activities. The biggest challenge is keeping at it. Pick activities that you really enjoy. Ideally, alternate between aerobic (cardiovascular) exercise (in which your heart rate accelerates into a target range for 20 minutes or more) and anaerobic exercise (such as weight training or yoga).

Variety helps. Pick more than one activity and alternate them. Include at least one thing you can do when the weather is poor, and have ideas for both summer and winter. Experiment. If you haven't tried something before, give it a shot (but use caution to avoid beginner injuries). Remind yourself that if you don't like it you can switch to something else.

Stretch first. Learn how to do stretching exercises properly, then make sure to do them before each exercise session. This can help reduce the likelihood of exercise-related pain or injury.

Exercise with a friend. Or make new friends when you exercise. This will increase your motivation and enjoyment of your activities.

Frequency is more important than duration. Try to spread your 150 minute minimum over 4-5 days each week.

Focus on enjoyment. Some research shows that people who exercise for enjoyment and challenge seem to show stronger mood improvements than people who exercise mainly to look better. Try to put an emphasis on how you will feel rather than how you want to look.

Nothing changes overnight. Use goal setting when developing a fitness program, and be sure to pick something achievable. For example, aim to swim once for 5 minutes rather than starting off by committing yourself to 70 laps a day.