Tired, Stressed, Forgetful? Your Sleeping Habits Might Be Doing More Harm Than You Think
Written by Michael Tanner
A junior doctor swerves into oncoming traffic. Declining cognitive function forces a consultant into retirement. A medical student’s anxiety becomes incapacitating. A registrar leaves their training program citing burnout.
And the common theme? Sleep deprivation.
Inadequate sleep is often worn as a badge of honour. It shouldn’t be.
Why don’t doctors sleep enough?
It’s the long and often unpredictable hours.
It’s cultural; the proud reflections of how little sleep was had, yet they’re still functional.
lt’s studying for seemingly never-ending exams - burning the candle at both ends.
It’s the racing mind at night, so difficult to switch off.
Why should I sleep more?
Sleep is really, really good for you. If you could take a drug that improved your capacity to learn, made you calmer, and reduced your risk of heart disease, stroke, cancer, dementia, diabetes and obesity, who wouldn’t take it? Instead of a drug, we have our beds, and a wonderful process that does all the above.
It’s important to dispel two common notions: “I only need four/five/six hours sleep”; and “I can catch up on the weekend”.
If you are sleep deprived, you are unable to accurately judge how affected you are. While you may wake up after a short sleep feeling “normal”, this is simply an adjustment to a much lower level of functioning, including poorer memory, attention, emotional regulation and health. A mutation of the DEC2 gene might mean you actually need less sleep at night – but such a mutation is so rare there is no test for it.
Nor can you “catch up”. After a week of sleeping 5-7 hours a night, even three nights of sleeping as much as the body allows is insufficient to return to baseline attention, compared to 9 hours per night.
What’s so bad about not sleeping enough?
Lack of sleep destroys memory. Why study if you can’t remember what you just learnt? Our capacity to learn diminishes through the day, and even a short nap is sufficient to lead to improvements in learning compared to not sleeping. Sleeping after learning is equally important for consolidating what you learned, moving short term memories into long-term storage. Research suggests some 20-40% more memory retention after sleep.
As for pulling an all-nighter? Your hippocampus shuts down, preventing the receipt of information that could be translated into memories. It is better to sleep and cement your study than continue burning the candle and risk the treasured information dissolving into the ether.
Ever wonder why you feel grumpy after a bad night’s sleep?
A night spent awake can lead to amplification in the emotional reactivity of the amygdala; the region of the brain involved in the activation of the fight or flight response, the region where anger and rage are triggered.
This effect is linked to the reduced functioning of the prefrontal cortex – the loss of the ability to rationalise – that occurs after poor sleep. Your striatum becomes hyperactive due to a loss of dopamine, making you crave the neurotransmitter's sweet sensation. This is why you spend the day on Instagram the day after a poor night’s sleep, unable to resist the dopamine rush.
How about if you had gone to the pub one night and stayed sober, but left at 2am?
You might as well be driving drunk, as your performance is the same as someone with a blood alcohol content of 0.08. Your performance gets exponentially worse the longer you are awake.
Chronic, milder sleep deprivation is as bad. In one study, more than half of truck drivers who slept five hours per night for five nights had at least one six minute period of drowsiness in their daily driving. You don’t drive drunk? Don’t drive tired.
Then there are the longer-term harms.
During sleep, glial cells in the brain shrink, allowing cerebrospinal fluid to clean neurons after the day’s activities. When there is not enough sleep, amyloid plaques can accumulate, leading to an increased risk of Alzheimer’s disease. Margaret Thatcher, former prime minister of the United Kingdom, and Ronald Reagan, former president of the United States, proudly abhorred sleep. Both developed Alzheimer’s disease.
Poor sleep increases the risk of suffering a myocardial infarction.
- Leads to weight gain because it increases the release of ghrelin, the “I’m hungry hormone”
- Leads to an increase in the natural release of endocannabinoids, giving you the so-called munchies, making you crave food.
- Shuts down the impulse control in the frontal lobe, leaving you unable to resist sugary treats
- Makes cells less receptive to insulin, leading to hyperglycaemia and eventually pre-diabetes or diabetes.
Poor sleep impairs your immune response. Compared to sleeping seven hours or more, getting less than five hours makes you nearly three times as susceptible to catching a cold. It reduces your immune response to the flu vaccine. It leads to chronic inflammation – increasing the risk of cancer – and when tumour cells do develop, poor sleep increases their rate of growth and spread.
The health costs of sleep deprivation are damning. Sleep disorders cost Australia $5.1 billion per year, including $540 million for health conditions secondary to these disorders. This doesn’t include the 20-35% of Australians who are chronically sleep deprived.
How can medical students and doctors sleep more?
Systemic issues prevent many medical students and doctors from getting adequate sleep. In the current culture, this is unavoidable.
But we can, and must, change the culture.
Start discussions about sleep; don’t glorify lack of sleep; discuss its benefits. Don’t laugh at your friend who goes to bed at 9pm. Don’t become a consultant who thinks the following generations should suffer because you did.
Take these steps to maximise sleep time and its quality.
- Have a bedtime routine. Go to bed and wake up at the same time every day. You want your brain to associate the time of day, and getting into bed, with sleep.
- Avoid lying awake in bed; this will weaken the associations your brain makes. If you are struggling to sleep, get up and do something relaxing until you feel sleepy.
- Avoid looking at screens in the hours before bed. Blue light suppresses the release of melatonin, leaving you thousands of extra sheep to count. Install F.lux or a similar program, which lessens the effects of blue light.
- Invest in your sleep. Install black-out blinds; buy an eye mask, and a comfortable pillow, mattress, and sheets.
- Cool down (physically). Your body needs to cool down to below normal temperature to sleep. Keep your room cool. Cool your core temperature by taking a hot shower (or better yet, a bath). This causes peripheral vasodilation and central vasoconstriction, shifting blood to the extremities.
- Cool down (mentally). Relax before bed. If it is a contest between sleep and study, sleep wins. Always.
- Avoid alcohol and caffeine. Alcohol is a potent suppressor of REM sleep, while caffeine has a half-life of about five hours. A quarter of the initial serving will still be in your system 10 hours after consumption.
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