You missed a couple of kickboxing classes. Or you haven't been to the track in a month. Whatever the culprit behind your workout hiatus, the lack of physical activity can leave you feeling guilty, self-conscious and out of control. In short, you've got a bad case of FWS: fitness withdrawal syndrome.

Before self-defeat prompts you to take up permanent residence on your couch, keep this in mind: Storing your sneakers away for a few weeks won't turn your muscles to mush. "We tend to go into that all-or-nothing mentality of, 'I didn't do it today, so everything's going to fall apart tomorrow,' " says Shape fitness editor Linda Shelton. "But that's not necessarily the truth."

To ease out of FWS:

1. Accept that workout interruptions will come up. Yes, treating yourself right means getting enough exercise (minimally, some sort of activity 30 minutes on most days). But it also means understanding that life will go on if you don't make it to Spinning class because you're stuck in traffic. Next time something thwarts a workout, rate how important this is in your life on a scale of 1-10. Chances are, one missed step class won't score high. Accepting that life doesn't always go as planned is the first step in overcoming FWS.

2. Be resourceful when time-pressed. Think of surprises as opportunities instead of obstacles, and you'll be able to handle schedule interruptions. Can't go to yoga tomorrow? If you keep an extra stash of workout clothes in your car, you could make a class tonight. Only have 20 minutes for a workout instead of your usual 60? Take the 20 and run with it, Shelton says.

3. Spice up your life with variety. Not only does changing your workout routine save you from the burnout blues, but from a physiological standpoint, it's better for your body. Instead of going for your third run this week, try a sport that you've always wanted to do but have never made time for. Also, vary the intensity of your workouts, Shelton says. By increasing your cardio one day and focusing on strength training the next, you'll feel less pressure to perform day in and day out.

4. Put yourself first. Your workout time is as important as getting eight hours of sleep a night; you need it. And when you don't get it, you feel slightly off. Shelton recommends writing your workout schedule in your calendar. Just seeing "walk after work" scrawled across today's date in ink can give you the incentive to commit to it.

Slack-off stats

What happens to your body when you go on an exercise hiatus? For those who maintain moderate fitness levels, Shape contributing fitness editor Dan Kosich, Ph.D., says, after skipping:

1 week, you won't see any changes in cardiovascular capability or strength. Often, when you lay off for a week after putting in several training sessions, it actually helps your muscles recover and you come back stronger than ever.

1 month, expect to huff and puff a little more during your morning jog. You've lost a slight amount of aerobic capability and strength, but nothing drastic.

3 months, pay attention to your body as you begin retraining; take it slowly. Your aerobic ability and strength have dropped moderately, and you're susceptible to injuries, especially if you jump right back into your advanced step class.

6 months, you'll be in the same cardiovascular shape you were before you ever set foot on the elliptical machine, and any previously achieved muscle.

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