How fast can you lose fitness?
Kelly Gillen, who completed the JFK50 Mile in November 2016, planned to take a two-month rest. Kelly Gillen, an avid runner, felt exhausted after running the long-distance, almost twice as long as a marathon. She assumed she would be ready to run again in January. The 38-year-old scientist who lives in Brooklyn, with her husband, and dog, soon realized that there was a problem after returning to the streets.
Gillen was shocked to find that her first run in 2017 was painful. She sought medical attention. Gillen’s knee pain was caused by a loss in cartilage beneath her kneecaps. This was confirmed after multiple visits to an orthopedist and two magnetic resonance imaging scans (MRIs). Before Gillen was able again to run, she had to undergo months of physical therapy and strength-training exercises.
Unintentionally, she took time off which led to a loss in fitness. She used running for years to relax and get her mind in order. After an injury, things changed. Gillen states, “I had to pay attention to every step.” She says, “I had to relearn how to run.”
She couldn’t run as fast as she used to and couldn’t get as far. Her focus was on her form and not pushing herself too hard. Gillen was happy to be able again to run, but it took months before she felt the movement as effortless and natural as before.
Experts say Gillen’s slow and steady approach to getting back into shape is the best. It doesn’t matter how long you have been away from exercise, it can still feel great to get back in the habit.
Kirk Campbell, MD is an assistant professor of orthopedic surgery at NYU Langone. He says that fitness loss can occur if you stop exercising for a prolonged period no matter your level of fitness. How quickly and how much fitness you lose will depend on your personal situation and the type of fitness you are referring to.
How quickly can you lose cardiovascular fitness?
Long-term, consistent cardiovascular training is essential for endurance athletes such as runners, swimmers, and cyclists.
Dr. Campbell says that this type of fitness will not disappear overnight, but it will decline over time. He says that cardiovascular fitness begins to decrease around two weeks after being sedentary.
The literature review was published in Frontiers of Physiology in October 2022. It examined existing evidence regarding “detraining” or losing fitness. Although the results of different studies may vary, it is clear that endurance athletes experience a decline in cardiovascular fitness and endurance after just 12 days of non-exercise.
Although there isn’t much evidence that fitness decreases after a few weeks of inactivity, Campbell states that those in good cardiovascular condition may take several months to lose all their aerobic fitness. Campbell also says that each person’s abilities will determine the timeframe.
Remember that, except for an injury, a break from regular exercise does not necessarily mean complete inactivity. According to the literature review, cardiovascular fitness in regular exercisers begins to decline after 35 days (five-week) of light, occasional exercise. This means that if you exercise a lot, and then reduce your intensity, you may also notice a decline in cardiovascular fitness.
How quickly can you lose strength?
Campbell says that muscle mass loss can have a negative impact on your ability to lift weights and carry groceries. However, this depends on many factors such as age, diet, sleep hygiene, fitness level, and other factors. Campbell cites a study that was published in May 2020 in the International Journal of Exercise Science. It found that even three weeks of training does not decrease muscle strength, thickness, or performance in sport in 21 male adolescent sportsmen.
An older study showed that age plays a major role in muscle strength loss. The effects of strength training on adults was studied in two age groups. There were 18 participants and 23 participants (aged 20 to 30). All participants experienced an increase in their one-repeat maximum strength after nine weeks of resistance training. The younger group saw a 34% increase, while the older group saw a 28% increase. The strength gained by the younger adults was only 8 percent, while that of the older ones was 14% after 31 weeks of detraining. The study found that strength declines more rapidly as we age but it is much slower than cardiovascular fitness.
Training breaks can be beneficial even if you lose some fitness
Even though you may lose some fitness from taking breaks during training, rest is still very important for your body and mind, especially after a hard training session. Campbell says that recovery is essential for both physical and mental health. It allows you to achieve greater fitness over the long term.
Neely Gracey is a certified running coach and is based in Denver. She says that she has always taken two weeks off at the end of every marathon season. She encourages her athletes to do the same. Gracey states that while some people want more time than others, it is important to give your body and mind time to reset and rest.
Five-time Team USA champion Campbell says that taking time off can help athletes avoid injury from overuse of muscles and reduce burnout.
There is a distinction between unintentional and intentional time off, such as after an endurance event. A short rest can help you avoid injury and burnout, but it shouldn’t be a permanent lifestyle change.
Why? Exercise after a break can bring on its own mental and psychological challenges.
Gillen claims that she was a terrible runner in this area. Gillen said that she struggled tremendously in this area.