We love to run. We have training plans, schedules, and blocks marked off on our calendars just for the “me” time on the open road (or trail or greenway). But then life happens — a big project, a sore ankle, a sick child, or — if you’ve been there — giving birth or having surgery. Suddenly, you’re out for days or weeks.
So how long is too long before we have to worry about losing the condition we’re in?
The answer is akin to asking, “How fast can I run in 5 years?” or “How far can I ride when I’m 52?” It depends — on a lot.
“There really isn’t a one-size-fits-all for this — we are all a study of one,” says Lisa Landrum, creator of runCLTrun and head coach and owner of ForwardMotionXC. “A lot of factors come into play, like how long you’ve been running prior to the break, or how much you’ve been training and at what intensity.”
Research backs that up, agrees Dr. Karan Shukla, a physician at Novant Health Randolph Family and Sports Medicine.
“It depends on the baseline level of functioning,” says Dr. Shukla. “It’s different for a high-level athlete or basic athlete, or non-athlete.”
A study of adolescent athletes who have been training for a year (I know, we’re past that, but it’s still good data) could go as long as three weeks without losing muscle mass and aerobic capacity.
On the other hand, beginners lost their fitness a lot more quickly. Researchers put sedentary individuals on a bicycle training program for two months, which increased their aerobic capacity, then took them off for another two months. The subjects regressed to pre-fitness levels.
And a study of active seniors in a residential home found 12 weeks off caused them to lose their fitness levels, but they could regain quickly after they returned to activity. Sedentary seniors who started a fitness program and then took 12 weeks off lost their fitness more quickly and had a longer road to regaining it, says Dr. Shukla.
Okay, we know most of us fall somewhere in between. When should we worry?
“In a moderately active person, 12 weeks of inactivity is associated with the most measurable decline in physical function,” says Dr. Shukla. “It’s too long.”
For active runners in training, two weeks is about the limit of time off before losing aerobic capacity. Studies back this up: Runners who’ve been training at least 4-6 months don’t lose the capacity for the body to transport and use oxygen during exercise for up to two weeks. After that, levels start dropping.
Landrum sees this “where the rubber meets the road,” so to speak, with runners she works with. “Theoretically and very generally speaking, aerobic capacity starts to decline after a week or two of no running,” she says.
But if you must — we all need time off sometimes — cross-training will get you through it and reduce loss.
“Strength training, cross-training, flexibility, and core exercises,” advises Dr. Shukla. “Your body has muscle memory.” He also acknowledges some illnesses or injuries require longer recoveries. Childbirth or surgery often require 6 weeks of rest. COVID-19, even in mild cases, can sometimes affect long-term health with fatigue or lung capacity. Start slow and build from there, he recommends.
“First, return to health, then add daily activities, then exercise,” he says. Remember that a holistic approach with daily sleep and a proper diet works best. From there, listen to your body as you rebuild your routine. “Engage in light exercise — a brisk-pace walk, then convert to a trot, and follow with a higher-intensity sprint after that. Maybe you’re not running that long run until you feel like you can engage at shorter distances at higher intensity,” he says.
How long will that take? Again, it depends on variables like your age and your pre-inactivity fitness levels.
“For every 2 weeks of inactivity, you should give an extra week to recondition,” says Dr. Shukla. “Give yourself a little time, and give yourself a break. The older you are, the longer it will take.” And give yourself a little grace — think long-term. “The last thing you want to do is recover and re-injure yourself on your first run, or be so sore you can’t run again for another week.”