What Happens When You Stop Your Fitness Habit?

It happens to us all the time: due to an injury, a trip abroad or a busy schedule at work, the routine of exercising and fitness is forced to stop. During this period of time, not only did I not exercise, but I was also likely to be lazy and overeat. Originally, I expected to take one or two breaks without going to the gym, but I accidentally extended it to several weeks or even months. Finally, my body shape and weight returned to the original point with a little achievement. The proper term in medicine is called deconditioned. According to research by the American College of Sports Medicine, about 25-35% of adults stop exercising after 2 to 5 months. How quickly the body's fitness declines after exercise stops is related to many factors, and some declines may be too fast to imagine.

1. Rapid decline in cardiovascular fitness after one week

The goal of aerobic fitness training is to increase the body's ability to transmit blood from the muscles and use oxygen. We usually use the maximum oxygen uptake (VO2 max) to measure it. According to Danielle Weis, a therapist at Spring Forward Physical Therapy Center in New York City, maximal oxygen uptake begins to decline after one to two weeks of inactivity, and heart function begins to decline. After resting in bed for 3-4 weeks, the resting heart rate can increase by 4-15 times, and the blood volume of the human body will decrease by 5% within 24 hours, and will decrease by 20% within 2 weeks.



2. The more experienced the bodybuilder, the slower the decline in cardiovascular health after stopping exercise

According to Brad Thomas, director of sports medicine at UCLA and an orthopedic surgeon, if you have only started exercising for a short time (within 6 months), your fitness will decline faster than if you have been exercising for more than 1 year. People come faster. You will lose up to 40% of your aerobic fitness, but despite this, your VO2max will still be higher than that of someone who has never exercised.

3. Rapid decrease in body flexibility

Michele Olson, a professor of exercise science at Auburn University in Alabama, says that if you rest for a period of time without stretching, you will lose your body's flexibility quickly. During periods of no stretching, muscles and tendons return to their resting lengths - especially when sitting at a desk for long periods of time. Olson notes that the loss of body suppleness can be felt in as little as three days, and becomes more pronounced after two weeks. She recommends stretching at least three times a week to maintain flexibility.



4. Muscle strength will begin to decline after two weeks

According to Olson, when you quit weight training, the muscles start to change within a few days. After the muscles are not getting their usual pounding, they will start to lose protein, which will be absorbed into your circulatory system and excreted in your urine. These small but important losses of muscle protein (the main building block of muscle fiber contractile units) can begin to occur within 72 hours of stopping training. Within 2-3 weeks, you can experience significant changes in muscle strength by returning to retraining with the original weight. Like cardiovascular fitness, long-term bodybuilders lose strength more slowly than those with less exercise experience.

5. Power Declines Faster Than Strength

Dr. Weis also said that after a period of inactivity, power (defined as strength over time multiplied by distance) declines faster than strength. Muscle strength will first begin to decline due to changes in the nerve's impact on the muscle fibers. Not long after that comes the actual muscle burn. During muscle depletion, protein is broken down at a faster rate but protein synthesis is slower. The time it takes to regain original fitness depends on why you stopped training in the first place - whether it was due to illness or lack of time.



6. Fitness declines faster when sick

People who stop exercising due to illness or injury lose more muscle mass and affect their cardiovascular health to a greater extent than healthy inactive people. The former will lose fitness twice as fast, Dr. Thomas said. Illness or injury puts far more stress on the body than slacking off. Weis, a physical therapist, also said that whether you are a professional athlete or a recreational fitness enthusiast, if you take a few weeks off from regular exercise, the level of dysregulation will be quite low. But once recovering from a fracture, surgery, or bed rest, it can take as long as 12 to 24 months to return to full fitness.

7. Maintaining an exercise habit is easier than we think

If you're planning to break your current weekly exercise routine, remember that getting in shape isn't just about training aggressively or not training at all. In fact, Dr. Thomas points out, we can maintain existing levels of fitness for very short periods of time. In order to achieve the goal of maintaining cardiorespiratory function and muscle strength, only 20 minutes of high-intensity interval training (HIIT, High Intensity Interval Training) is required per week. But to be truly high-intensity, the exercise you do must increase your heart rate to between 80% and 90% of your maximum heart rate.

8. Aging affects decline in physical fitness

Dr. Thomas also said that as the body ages, the rate at which your muscle strength and fitness decline may triple. This is mainly to reduce the hormonal content in the body. With age, the content of human growth hormone (HGH, Human Growth Hormone) is lower, so the decline in physical fitness is more difficult to recover. Old age will also gradually lose the ability to cope with stress and restore physical fitness through stress hormones such as cortisol, so the above mechanisms will make older people more fatigued after exercising. According to a 2008 paper published in the Journal of Aging and Physical Activity, older athletes generally require longer recovery times after working out.

9. It takes three weeks to recover from the amount of no exercise for a week

According to Irv Rubenstein, founder and exercise physiologist at STEPS Scientific Fitness Facility in Tennessee, after a period of rest, the nervous system loses the same priming power it had before the rest. This is due to the loss of the neural stimulation that allows us to use the same force to lift heavy objects. When we resume weightlifting after a period of rest, we may be able to lift the same amount of weight, but with a force above our normal ability, which may cause tissue damage. Putting more effort into doing the same weight lift will also require more rest time to recover. So once a novice stops exercising, he may have to start from scratch. It may take more than a month for experienced veterans to stop exercising to return to their original fitness.

The full text is excerpted from an article on the livestrong.com website of the Live Strong Foundation
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