As I do a fair amount of night shifts as a Junior Doctor, I thought it would be topical to talk about the importance of sleep and why the attitude of “I’ll sleep when I’m dead” could be not only pushing you there faster, but reducing your quality of life while you’re at it. Sounds dramatic hey!? It’s really not. Lack of sleep can also have an impact on your muscle growth, which is less than desirable.
We can talk about the four stages of sleep, what they are, and how they relate to muscle growth. In stage 1 of sleep, you are drifting off, easily woken. Brain wave patterns seen are associated with muscle memory and logging movements done throughout the day. This comprises around 5% of a night’s sleep and occurs in 1-7 minute bursts. Stage 2 makes up 45% and these 10-25 minute bursts of light sleep see the body temperature drop and the body relaxes in preparation for deep sleep. Here the body starts to produce Human Growth Hormone (HGH) from the pituitary gland. This hormone helps to promote muscle growth and regulate metabolism. Moving onto stage 3, 25% of sleep, the sleep spindle brain waves stop, blood pressure drops, and blood supply to the muscles increase. This is the most restorative stage of sleep occurring in 20-40 minute bursts. More HGH is released also supporting the immune system, along with Prolactin. This hormone has anti-inflammatory properties and can help joint recovery. Finally, stage 4. This usually occurs for the first time around 90 minutes into sleep and makes up 25% of sleep in 10-60 minute bursts. This is termed Rapid Eye Movement (REM) sleep, as here your eyes will cascade side to side. This is when we dream and the muscles are switched off so that we do not re-enactment them! Oxygen supply to the muscles increases allowing for the clearance of lactic acid. These four stages repeat throughout the recommended 7-10 hours of sleep.
Here are some general scary facts about sleep deprivation. The day after daylight saving in spring when we lose an hour of sleep, heart attacks increase by 24% compared to a 21% decreased the day after we gain an hour in autumn. Crazy right!? Here’s another: A study of healthy young males restricted their sleep to 5 hours a night for 8 nights compared to a fully rested state of 7 nights of 8 hours and 3 nights of 10 hours sleep and measured serum testosterone. They found a 10-15% DROP in testosterone levels when sleep deprived. Not helpful for anyone! Natural killer cells are part of the immune system and work as part of our security team. One study showed that even after just one night of sleep deprivation, these cells reduced by 30% of baseline levels, reestablishing after a night of sleep. Scary stuff. In terms of muscle growth, a study in 2011 compared a group of participants who were limited to 5.5 hours of sleep a night for 2 weeks compared to a group allowed 8.5. Both groups had moderate caloric restriction. The group with less sleep lost 55% LESS fat but lost 60% MORE muscle than the 8.5 hour group. That’s not what you want from a caloric deficit.
So what can we do about it? Here are some tips to improve your sleep, mostly focusing on sleep hygiene. DO have a regular sleep pattern, ideally you would go to bed and get up at the same time everyday, even on your days off (I know, I know, who does that!?). DO keep the bedroom for sleeping, no watching TV in bed or reading over that report! In fact, try to avoid any electric screens 30 minutes before sleep. DO keep it cool, your body needs a temperate drop of 1 degree to fall asleep and stay asleep so don’t be cooking under that duvet! DO some low intensity exercise before bed. DON’T do high intensity exercise before bed. DON’T have too much caffeine or alcohol (ideally none - again, unrealistic but just so you know). It’s worth adding that sleeping pills are not the answer. They do not produce the sleep I’ve talked about and come with a hell of a lot of their own risks! Naps may also be helpful to catch up on missed sleep should the recommended 7-10 hours be impossible but you will not get the aforementioned health benefits as you do from a solid stint of sleep. It’s all common sense really - prioritise the shuteye!
Dr Stephanie Hill BSc MBBS
