I’ve written a lot about exercise. A lot about training. A lot about the best systems for muscle growth and slimming down. What I’ve not covered very much (if at all) is rest, and its absolutely essential role in exercise. I’m not talking about rest between sets or bursts of HIIT, I’m talking about actual rest – taking some time out to let your body recover.
Training may act as the stimulant to growth and development, but sleep is when the adaptions actually take place
The reason I’ve neglected the subject until now is because it’s not something that I, or many other gym goers, prioritise.Training may act as the stimulant to growth and development, but sleep is when the adaptions actually take place. Miss out on sleep and adequate rest, and your gains could be severely hampered.
Sleep for repair and development
One key reason for this is that the release of Human Growth Hormone (HGH) spikes with the onset of sleep. HGH stimulates the growth and repair of cells – not simply the repair of muscle cells damaged during intense training, but the damage done to your muscles during normal day-to-day activities.
Researchers suggest that around 70-75 per cent of HGH is released during sleep and, in particular, the deep sleep that usually occurs around an hour after you first hit the hay. Without that sleep, studies show no rise in those all-important HGH levels* and thus a lower rate of cell repair and growth.Sleep and exercise are the two main stimulants of HGH release, with sleep being the most important. In fact, sleep deprivation can suppress the release of HGH, particularly later in life**.
But aside from HGH release, getting a good night’s sleep will mean you are far more likely to hit the gym in the first place, and will perform that much better when you do go. So, if you’re training hard, make sure you prioritise your sleep and get at least 7-9 hours per night.
Rest for muscle development and recovery
However, it isn’t just sleep that should be taken into consideration when you’re training. The length of time you leave between your sessions could be the difference between improvement, stalling and even potential decreases in your strength.
Research has shown that ‘muscle protein synthesis’ (the rebuilding of muscle) is elevated in humans by 50 per cent four hours after a heavy resistance training session, and by 109 per cent after 24 hours. Thereafter, it takes a sharp decline, returning to baseline levels at around 36 hours post-exercise***. This would suggest that 36 hours should be the minimum amount of time you should leave it before working the same muscle group again.
Notice here that I say the minimum amount of time. The majority of online resources site 48 hours as being a good amount of time to give your muscles to recover properly. But, as with most things ‘fitness’, this completely depends on the individual – how fit and healthy they are, and the intensity of their training. You must do what feels right for your body. This applies to both resistance training and cardiovascular activities.
Some sessions, such as low intensity weight training and swimming, will take very little time to recover from. Whereas high intensity squats and running, may well take a bit longer.
As a rule of thumb, I would advise leaving 48 hours between gym sessions if you are following my free programme. If you are following a more advanced programme – training only one or two muscles groups per session – I would advise giving your muscles 72 hours to recover. For instance, if you do an intense back workout on Monday evening, I would refrain from directly focusing on your back again until Thursday evening, unless you are an advanced weight lifter.
Rest for mental well-being
The last, and almost most important aspect of rest is for mental well-being. The benefits of exercise for mental health are discussed regularly by the media, doctors and PTs. However, what isn’t discussed as much are the effects of training too much.
Overtraining occurs when the stress of exercise placed on the body exceeds the body’s ability to recover. This isn’t simply a case of being tired after a hard workout – symptoms of overtraining include an elevated resting heart rate, insomnia, muscle soreness that lasts for many days after an activity, poor performance in your workouts and daily activities, and poor mental well-being usually characterised by low self-confidence, demotivation and, in some cases, depression. Yikes!
Scientifically speaking, it’s probably unlikely that you have genuine ‘overtraining syndrome’, which the European College of Sports Medicine warns could end your athletic endeavours and takes months to recover from. However, ‘overreaching’ yourself can have very similar symptoms. According to a paper published in the British Journal of Sports Medicine by Richard Budgett of the British Olympic Medical Centre, during a period of hard training, changes in mood can occur, including “reduced vigour and increased tension, depression, anger, fatigue, and confusion”. However, it notes that “all these changes are physiological and normal if recovery occurs within two weeks”.
Putting it simply; giving yourself time to recover is absolutely essential. It’s no use going all out on your new fitness regime if you end up doing yourself long term damage. Budgett notes a study of college swimmers who were allowed to train according to their mood: hard during a positive mindset, and lower intensity if their mood was deflated. He states that the result was 0 per cent burn out during the year. A reduction from 10 per cent in previous years.
In essence, that’s the key point! Yes you love training, and yes “overreaching is a vital part of training for improved performance,” Budgett notes. However, it’s important to listen to your own body. Training should be for your health. If it’s starting to affect you detrimentally- whether physically or mentally – it’s time to take a step back. Be your own best friend and get some rest! Trust me, you’ll come back stronger.
* Growth Hormone Secretion During Nocturnal Sleep in Normal Subjects The Journal of Clinical Endocrinology & Metabolism (1969)
** Age-dependent suppression of nocturnal growth hormone levels during sleep deprivation Neuroendocrinology (1996)
*** The time course for elevated muscle protein synthesis following heavy resistance exercise Can J Appl Physiol. (1995)