This Is Exactly What Happens If You Miss a Workout . . . or 2 or 3 or 12

Updated on 12/1/2017 at 5:10 PM

POPSUGAR Photography | Kathryna Hancock

Did you miss a workout? It's OK. Taking a rest day is actually highly recommended and essential for your recovery and muscle building!

It's important to know that missing a workout here and there isn't going to derail you, unless you let it. In fact, we got a great pep talk from Tone It Up trainers Karena Dawn and Katrina Scott. Karena told POPSUGAR to dive back in as quickly as possible.

"It's all about how you recover [from missing a workout], too," Katrina added. "If we have a bad week where we really couldn't get anything in . . . it's almost like we keep going because we think we already screwed up." How do you keep yourself from that? "If you miss a workout, you can't beat yourself up. Just get back out there and get your workout in the next day."

So now that we've got that out of the way, what happens physically when we miss these workouts? The short answer: it depends on what your workout schedule is usually like. We got the scoop on the physiology — and the timeline breakdown — from Liz Letchford, MS, ATC, PhD candidate, and personal trainer at DIAKADI. She calls a period of missed workouts "detraining."

"You can't beat yourself up. Just get back out there and get your workout in the next day."

It turns out that weight trainers have the greatest risk of losing strength over time. "With isometric training not including high-intensity exercise (classic weightlifting), strength loss can occur at a rate of 0.3-percent to 0.8-percent per week," she told POPSUGAR through email. But those who have more of a cardio schedule typically keep their strength even when they take time off. Also of note, the more advanced you are, the more you have to lose. "Those who are highly trained show a greater magnitude of strength loss when compared to untrained or moderately trained individuals."

She told POPSUGAR the "performance decrease" is because the connection between your brain and your muscles isn't firing, and that connection becomes weaker; it happens during the first two to three weeks of missed exercise. After that happens, "the muscles undergo a process that causes their fibers to get progressively smaller."

Detraining Timeline

3 days: You probably won't notice any outward effects, but your body will start to make changes internally. "The body recognizes that it needs to mediate the loss of muscle fibers and begins to make changes to preserve the muscle. You won't notice much, and you won't gain fat as long as your diet doesn't drastically change."
10 days: "The muscle physiology changes and the physiological pathways that lead to muscle atrophy begin." Translation: you start to lose tone.
2 weeks: This is the point where you start to lose muscle mass, but don't worry — you won't lose strength. If you're used to using eight- to 10-pound weights at the gym, you should be able to get back in there and resume as if you'd never been gone. "Power athletes [think HIIT, cardio, running] will retain their strength, while strength athletes [think bodybuilders] will see losses at this time." You shouldn't see a major shift in weight, though, as she told us "there are no changes in body mass or body-fat percentage."
3 weeks: Liz described a "significant reduction in anaerobic power performance during activities like sprinting or HIIT."
4 weeks: At this point, you're going to notice that you might be a little out of breath when you get back to the gym. Technically speaking, this includes "up to a 10-percent decrease in max force production of muscle (1RM)" and the beginnings of "a decrease in VO2max (aerobic capacity)."

6 weeks: "Strength can still be maintained depending on activity," Liz said, but you'll keep losing power, meaning you'll definitely feel more tired when you hit the studio or gym again. "Anaerobic power performance during activities like sprinting or HIIT continues to be negatively affected."
6 to 8 months: After a while, you'll lose a good amount of strength — weights are going to feel heavier, and moves that were once easy for you will feel extra challenging — but the good news is you can definitely bounce back and quickly. "One study found that during 32 weeks of rest, a group of women lost a considerable amount of extra strength they gained during a 20-week training program," Liz said, "but they gained the strength after only six weeks of retraining."
2 years: "Even after two or more years of detraining, muscle has the ability to retain up to 15-percent higher force than before the training program started," she said. What this means is even if you take two years off from exercising, you won't ever go back to square one where you started. Your muscle memory is really your saving grace here. "And if after a period of detraining, one wants to start it back up again, those who have experience with training will build strength quickly. This is because muscle memory stays long after muscles have atrophied."

Like we said earlier, taking a rest day is not only OK — it's encouraged. We can't emphasize that enough. Don't be too hard on your body! Listen to it, and be sure to keep up with the TLC (recovery, foam rolling, stretching, and nutrition) just as much as you keep up with your badass workout schedule. OK? OK.