To improve, add intensity

You can strengthen your heart and lungs by adding distance, time or intensity when you exercise. And the most recent evidence shows that boosting intensity works more efficiently than increasing time or distance.

When you walk quicker, cycle harder or swim faster, it can also take less time to build heart and lung strength. That's an extra perk for the time-crunched.

Even seasoned exercisers can boost their health benefits and improve VO2 max by increasing the duration or intensity of their workouts. Interval training is one way to increase intensity. High-intensity interval training alternates bursts of more-vigorous exercise with intervals of lower intensity exercise. You can modify the intensity and duration of each interval to suit your physical activity goals. In order to make progress, you need to spend as much time as possible at, or close to, your VO2 max.

Whatever your fitness level is today, the payoff for pushing it just a little harder is both immediate and long lasting. Why not get started right now?