Several factors influence how quickly you lose fitness gains. Your overall fitness level, age, illness, and length of rest periods can all impact how quickly your ability to do cardiovascular and strength training programs changes. Rest is important, but don’t allow a few days off to turn into several weeks. Understanding how quickly your fitness can change is a good motivator to stick to your exercise routine.

Cardiovascular Fitness

Cardiovascular fitness is achieved by improving how efficiently your body transports and uses oxygen, called VO2 max. The more fit you are, the better you’ll maintain your fitness. One study found that athletes who trained for a year and then stopped exercising decreased their aerobic conditioning by only 50 percent after three months. By comparison, similar studies on beginner exercisers show that gains made in eight weeks of training were completely lost within eight weeks of stopping exercise.

Strength

Research shows that we lose strength at about half the rate it was gained. So if you perform weight training for eight weeks and then stop training for eight weeks, your gains would decrease by about 50 percent. What appears to change more drastically are the muscle fibers related to sports-specific training. For example, distance runners work to develop slow-twitch muscle fibers that aid in endurance. While overall strength can be maintained for a few weeks after stopping exercise, there is a more rapid decrease in the slow-twitch muscle fibers related to athletic performance.

Best Ways to Maintain Fitness

The best way to reduce the risk of canceling out all your hard work is to avoid becoming sedentary. We all have busy times when we need to cut back or need breaks from training. Research shows some fitness can be maintained for a few months with one workout a week at an intensity of at least 70 percent of your VO2 max. Even if your workouts are not as intense as they once were, squeezing in some activity is important to prevent losing fitness gains. Maintain an active lifestyle by walking to complete errands, taking the stairs instead of the elevator, and performing daily activities that keep you moving (like cleaning and yard work). When you can't make it to the gym, start your day with a quick circuit workout. These efforts will make it much easier to return to your regular exercise routine when you are ready.

Lori Rice, M.S., is a nutritional scientist and author with a passion for healthy cooking, exercise physiology, and food photography.