If you haven’t worked out for 2 - 3 months, you have lost half of your aerobic fitness. During this hiatus, your lung capacity has shrunk (not breathing in the same volume of air), your blood vessels have contracted (heart is not moving as much blood through the circulatory system), and your muscles have lost a significant amount of their strength.
Starting Over Again
Depending on why you quit working out, you may want to get cleared by your doctor to begin working out again. Don’t expect to start up again with the same intensity as where you left off. The good news is that your workouts will start to get easier in 2 - 3 weeks and by the 4 - 6 week mark, you’ll be back!
Now is more important than ever to do a good warm-up and cool-down. Devote time to these pre- and post-workout activities (should include light aerobic exercise and dynamic stretching). You don’t want to suffer a debilitating injury that could delay you even longer from getting back into shape.
The Process of Getting Back Into It
First couple of weeks go light; 2 to 3 days per week for 30 min. a day. Gradually increase days and duration of your workouts until you can go up to 45 min. For strength training, start with half the weight you once used and half the number of repetitions, then gradually add more weight and increase the reps. Runners start by walking briskly for 30 to 45 minutes, then insert 1 minute jog/slow run into every 4-5 minutes of walking. Over time, you’ll be back!
Do Something Different This Time
People stop exercising for various reasons. If you stopped because of boredom, try some other form of exercising. Instead of running, try biking. If you like to run outside but can’t due to extreme weather either buy your own treadmill or join a gym so you can run inside. Sometimes all you need is an exercise buddy. Not only will that person keep you motivated and accountable, it is good friendship and gives you something to do while exercising.
The important thing to remember when starting back on an exercise program after a long break is to start slow, warm-up/cool-down and gradually work up to where you were (or even better). You didn’t get into shape overnight the first time, nor should you expect to this time.