Lack of sleep has many detrimental effects for the body. New study published in the journal Physiological Reports found that just one night of sleep loss reduces muscle protein synthesis by 18% and decreases testosterone levels by 24%. In addition, levels of cortisol increase by 21% in just one night of sleep deprivation.
Sleep is often undervalued. Many of us treat sleep as a means of getting energy for the following day, energy to do our work, run our projects, at times being able to merely function, especially when kids are small, and sleep is compromised. However, for our body sleep is perhaps a most significant factor that differentiates good health and ill health.
Our body works on a 24-hour circadian rhythm, where all major functions, our organs, including body tissues, blood vessels have their own circadian clock. While some of those functions and organs perform their work during the day coinciding with our highest levels of activity (such as our digestive system, for example), others become active when we sleep. Our body has evolved to prioritise some of its functions for the periods of our main rest - sleep. The brain consolidates memory, repairs cells and releases toxins that the cells have accumulated from consumption of nutrients during the day. Blood vessels renewal also occurs during our sleep.
The study in Physiological Reports aimed to investigate whether sleep had an effect on muscle synthesis and our metabolic profile.
Inadequate sleep has long been linked to the disruption in hormones production, those responsible for hunger and satiety (ghrelin and leptin, respectively), ensuing higher energy intake, high insulin resistance and risk for diabetes type 2. Read more
This study is the first to showcase in clinical settings that just one night of sleep loss acts as a catabolic mechanism, promoting loss of muscle mass and function. The participants were healthy men who had normal sleep patterns prior to the study. Both, the study group and the control group, were given a supper, and while the control group were allowed to go home to sleep, the study subjects were kept awake in a partially-lit room with TV or books of choice. In the morning both groups were given breakfast that was specifically prepared to include sufficient protein in order to observe muscle protein synthesis. The study group had 18% decrease in muscle protein synthesis and also a 24% decreases of testosterone.
Muscle loss associated with ageing, or sarcopenia, is a problem for our population. Sarcopenia involves decrease in the skeletal muscle mass, and also muscle strength and function. Because muscle is an organ that performs many functions in the body, often sarcopenia has far-reaching adverse outcomes - low rate of convalescence from illness or injury, and death.
One study reports that due to various cellular and molecular pathways involved in protein synthesis, such as growth hormone, insulin-like growth factor, testosterone, cortisol and insulin, increasing lack of sleep that occurs with ageing interferes with the regulation of these, enhancing catabolic pathways in the skeletal muscle. Read here
The study also found that cortisol levels went up by 21% in the group who experienced sleep loss. Regular high levels of cortisol lead to increased hunger, high energy consumption, excess weight and high insulin resistance. The connection between lack of sleep, high cortisol and increased calorie intake has two possible explanations. Firstly, a sleep-deprived body is constantly trying to wake itself up: to do that it raises cortisol - the hormone that raises energy levels. Secondly, when cortisol production increases beyond a healthy to our body baseline, it impairs the body’s sensitivity to insulin. This means one needs more insulin during those hours in order to keep their blood sugar in the goal range. This results in increased hunger and cravings for high-palatable foods, which are high-sugar high-fat foods.
What can you do if you regularly under sleep?
To reverse loss of muscle mass the best approach is to do strength-training exercises, also ensuring you have adequate nutrition for your body. If you are new to strength training, start from simple basic bodyweight exercises such as squats, lunges, push-ups and abdominal exercises. Squats, for example, are an excellent functional exercises, which means that performing those exercises regularly, your body will get stronger in everyday tasks. Squats strengthen your abdominals, your back, your knee joints, and these areas are the most common injury sites when we age.
Try to reset your sleep.
Your body needs 7+ hours of uninterrupted sleep. This means that if your overall sleep during the night was 8 hours, but you had a toilet break and you also woke up to look at your phone/ alarm clock, this interrupted sleep is not enough for your body.