Once you pause, what happens to all those hard-won fitness milestones?

Sometimes things come up — Yom Tov, an injury, vacation — and you have no choice but to break routine and skip your regular fitness sessions. Once you pause, what happens to all those hard-won fitness milestones you earned with your regular exercise schedule? How long does it take your body to lose fitness?

Cardio Change

The loss of fitness — or detraining — happens over time. Cardiovascular fitness is affected first. Within the first two weeks of detraining, blood volume decreases. The heart pumps less blood throughout the body, which means less oxygen is available to muscles and cells, causing breathlessness. For endurance athletes, the change is even more drastic. Researchers noticed their cardiac structure changed, and the ventricular wall thickened. If you return to exercise after a two-week break, you may feel winded more quickly, and notice an overall diminished aerobic ability.

Endurance

Next hit is endurance, your body’s ability to maintain an exercise for a period of time. A regular fitness schedule promotes cell health by renewing mitochondrial production. But after three weeks, mitochondrial output begins to drop, and the body’s lactate threshold lowers, causing you to feel fatigued faster. If you restart exercise at this point, you may find you tire more easily. After eight weeks of detraining, muscle mass decreases, as does the maximum amount you’re able to lift. It takes longer to lose strength than aerobic fitness, though other factors contribute to the rate of loss. Level of fitness is a contributing factor. Athletes seem to lose strength at a slower pace. A 2020 study found that male athletes didn’t lose muscle thickness, strength, or performance in sports after three weeks of detraining.

Take a Break

Much of this scientific research was conducted using groups where there was a complete cessation of activity. If you need to take a break from exercise, for whatever reason, you likely won’t be completely sedentary. And even while on these breaks, there are ways to maintain fitness so that you won’t lose all your hard-won gains.

One way is to keep moving throughout the day. Take a short walk — or a hike, if you’re on vacation. You can have an “exercise snack,” which is a tiny fitness session that can last anywhere from 30 seconds to five minutes. It can be anything that gets your heart rate up: running up a flight of stairs, doing 20 jumping jacks, skipping rope, or doing squats or push-ups. A few exercise snacks throughout the day can add up to a respectable amount of vigorous activity.

If you need to take a longer break, you may want to consider cross-training or switching to a different sport. If you have to take a break from running, consider swimming or cycling. If you need to take a break from strength workouts, consider yoga or Pilates.

Taking a break can actually be good. For endurance athletes or anyone training for a long race, a break after the big day can be good for the mind as well as the body. Time off allows the body to rest, preventing injuries and burnout.

Regaining Fitness

Once you’re ready to return to exercise, the news is pretty good.

Even if you had to take a break, it’s possible to regain your fitness.

Research shows that people who have exercised regularly retain “muscle memory.” Muscles may shrink, but they don’t completely disappear, making it easier to get back to where you were before your break. With moderately hard workouts, it’s possible to regain about half of what you lost in ten to 14 days.

Regaining the rest of your fitness will depend on other factors. Serious athletes may need more time because they have so much more ground to cover.

Some studies have found older adults caught up in less than eight weeks after a 12-week break. For most people, it can take anywhere between two and 12 weeks.

Just remember when returning to exercise after a long break, take it slow. If you want to return to running, start with a walk or jog. If it’s strength workouts that you’re returning to, start with lighter weights until you feel strong enough to manage the heavy ones. (If you’re recovering from an injury, consult with a doctor first.)

The Age Factor

Age also plays a role. Another study suggests that older people lose strength at nearly twice the rate of people in their twenties. Researchers studied two age ranges: 20-30 and 65-75. Each group had nine weeks of strength training that produced an increase in strength. After 31 weeks of detraining, the younger group lost eight percent of their strength gains, while the older group lost 14 percent.

(Originally featured in Family First, Issue 931)