In 2017, famed long-distance runner Ron Hill broke his record for 52 years and 39 days consecutive race by taking a day off after feeling unwell during one of his races.
Hill writes in his autobiography that he ran at least a mile a day and made it his business to train 13 times a week. His training took place without a coach and was conducted on a trial and error basis.
Although he was successful – he even competed twice in the Olympics – he sometimes described symptoms of overtraining. These included sore and heavy legs, increased susceptibility to colds and infections, and weight loss. Although Hill found a training regimen that helped prepare him for competition, he wondered if some of his substandard performances were a consequence of not taking rest days.
When starting a new fitness regimen, we are often told that it is important to take “rest days” between workouts. The reason many recommend rest days is to allow the muscles of the body to recover from any damage suffered during workouts and allow them to grow. And many scientific studies show that rest days do indeed play an important role in helping us maintain good health and fitness.
We generally define rest as a period of time without any training. For most people, this is usually around 24 hours between workouts. However, recovery is different and can indicate a time span of several minutes to several hours (such as taking a short break during training between rounds). Recovery could also indicate the time required to induce some form of physiological adaptation, such as the observed rapid increase in plasma volume, which may improve aerobic capacity. But how necessary are rest and recovery as part of a training program?
Take a break
Most studies indicate that rest and recovery between workouts are both necessary to help the body adapt and recover from its last workouts. Exercise forces us to use up our body’s energy stores (mainly carbohydrates) and fluids (to produce sweat), so rest and recovery gives the body time to replenish these energy stores.
Several studies have shown that the body needs at least 24 hours to completely replace our muscles. carbohydrate store. Maintaining an adequate store of muscle glycogen (glycogen is the body’s carbohydrate store) is important for training and maintaining stable blood sugar levels.
However, less time is needed to recover our fluids. Numerous studies have shown that it only takes about one to two hours to replace our lost fluids in the form of sweat during exercise. But our bodies still need many hours rest after exercise to maintain hydration due to continued urine production.
Working out can also damage our body tissues. In some circumstances, this damage can be beneficial, but is not an essential part of building muscle. But for muscles to recover and improve (known as physiological adaptation), they need Several weeks of exercise and recovery cycles.
Research shows that our body needs a longer rest period to build muscle tissue (protein synthesis). But since protein turnover for muscles, tendons and ligaments is between 0.4-1.2% per daythis shows that there is a constant exchange of protein in our body related to food intake, urinary nitrogen excretion and the added effect of exercise.
The hours right after the initial workout may actually be the most important for this to happen. Researchers reported that a three-hour feeding regimen of whey protein was more effective for increase protein synthesis than feeding every 1.5 or 6 hours over a 12 hour period.
Many other adaptations that occur as a result of training (such as increased activity of enzymes and glucose transporters, which are essential for oxygen consumption and fuel utilization), require a period of 12 hour overrun before changes are detected. These changes are important because when we increase our exercise intensity, we have to use glucose instead of fat to fuel our exercise.
Longer-term adaptations, such as increasing the number of blood vessels in our exercised muscles or increasing the size of the heart, are a much longer process, requiring months of training and rest to observe everything. measurable change. These two adaptations are essential to increase our aerobic capacity.
There has also been a lot of interest in the quality of rest, and sleep deprivation has been used as a tool to examine the effects of disturbed rest on physical performance and physical and psychological function. An extensive study has concluded that sleep disturbances can have a harmful effect on performance, such as a reduced time to exhaustion – but they were clear that sleep deprivation had many negative effects on cognitive function.
Overwhelming evidence also shows that rest days are also extremely important in preventing overtraining syndrome. Overtraining syndrome can lead to fatigue, sleep loss, weight gain, depression — and can even lead to decreased performance and stalled progress.
In general, it seems that one day off per week is good advice and is supported by the scientific evidence, especially when it comes to repairing tissue, building and adapting skeletal muscle, and restoring fuel stores. It can also reduce mental stress. Although Hill has set world records at distances between 10 and 16 miles, he is an exceptional example – and even admitted that trying to run every day could have hurt his performance at both Olympics. Based on the evidence, taking a day off seems to be as important for progress and fitness as exercise itself.