After Kelly Gillen completed the JFK 50 Mile in November 2016, she intentionally prepared to settle into a two-month break, give or take. The long-distance run, nearly twice the length of a marathon, had taken a lot out of the avid runner, who assumed she’d be raring to go again come January. But the 38-year-old scientist, who lives in Brooklyn with her husband and dog, quickly realized there was a problem when she hit the pavement again after her hiatus.
Gillen’s first run in early 2017 was unexpectedly painful, leading her to seek medical attention. Multiple visits with an orthopedist, along with two MRIs (magnetic resonance imaging scans), revealed that Gillen’s knee discomfort was due to a loss of cartilage under her kneecaps. She had to spend months in physical therapy and doing strength-training exercises before she was able to run again.
The unintentional time off resulted in a loss of fitness. For years, she used running as a way to clear her head and zone out. But post-injury, things were different. “I had to be very aware with each step,” Gillen says. “I basically had to relearn how to run,” she says.
She couldn’t go as fast or as far, and she couldn’t zone out because she was so focused on maintaining her form and not overdoing it. Although Gillen was thrilled to be able to run again, it was months before the movement felt as natural and effortless as it had before.
Whether you’ve stopped exercising because of an injury or some other reason (maybe the pandemic threw a wrench into your workout routine), fitness experts say Gillen’s slow-and-steady approach to starting back up again and regaining fitness is ideal. And yes, no matter how long you’ve been on a break with exercise, getting back into it can feel just as fantastic for you as it did for Gillen.
Kirk Campbell, MD, assistant professor of orthopedic surgery at NYU Langone, says fitness loss is inevitable if you stop exercising for an extended period of time — no matter how fit you are. But exactly how quickly you lose fitness, and how much you lose, depends on both your personal circumstances and what kind of fitness you’re talking about.
How Quickly Do You Lose Cardiovascular Fitness?
Endurance athletes like runners, cyclists, swimmers, and dancers build up cardiovascular fitness (also called aerobic fitness or endurance) over sustained, consistent cardiovascular training.
This type of fitness won’t disappear in a matter of days, but it will decrease over time, according to Dr. Campbell. Generally, he says, cardiovascular fitness starts to noticeably decrease after about two weeks of being sedentary.