This time of year sleep seems almost impossible. If it’s not the late social evenings that make the most of the long summer nights, it’s the increased humidity and temperature keeping us tossing and turning well after the lights are switched off. Instead of coming back to work feeling refreshed after a break, I know many people whose post-holiday blues are exacerbated by sleep deprivation.
Though some of us seem to get by on little sleep, we are understanding more and more the adverse effects of getting less-than-optimal sleep on our overall physical and mental health. This may seem largely removed from nutrition and food, but you’ll know yourself that a night of sleep deprivation (i.e. less than six hours' sleep) affects the food choices we make. Conversely, our food choices can have an impact on our ability to get a good night’s sleep.
Research shows that lack of sleep increases insulin resistance, making it difficult to get energy into our cells. This contributes to the fatigue that can cause us to crave highly processed foods to help boost energy, which in turn can send our blood sugar and energy levels plummeting. Lack of sleep also enhances our brain’s feedback-reward circuits; not only do we crave more high fat and sugar foods, we derive more pleasure from them. Memory consolidation and reaction time is impaired, our immune system is suppressed and markers of brain injury in our bloodstream are raised when we are sleep deprived. And this is all after just one night!
Long-term sleep deprivation is linked to increased risk of adiposity, type 2 diabetes, cardiovascular disease, neurological conditions, some cancers and overall early mortality. We once thought the main role of sleep was to allow us to rest for the next day. However, we now know that optimal sleep is important for many of our metabolic processes, beyond allowing us to be horizontal with our eyes shut.
Across the four phases of sleep our body undergoes physical and emotional repair that isn’t able to happen at any other time. Musculoskeletal tissue repair, gene regeneration and hormone production all happen when we sleep. Memory consolidation and retention is solidified during sleep. Throughout the day there is a build-up of metabolic waste that requires clearing out —this includes beta amyloid plaques which are associated with Alzheimer’s disease risk. The clean-up is executed by our glymphatic system, something scientists discovered only a few years ago. Without sleep, these waste products build up and increase oxidative damage in our brain which is implicated in the increase in neurological conditions seen today.
Common causes of sleep deprivation
1. Our 24/7 society means we are working longer hours, making it difficult to unwind at night. If we aren’t working on computers, we might be engaged with them (or other devices) as a way to unwind from the stress of the day. The exposure to the blue light emitted ("blue" is a spectrum of light) disrupts our melatonin production, and subsequently the amount of time spent in each sleep phase. Melatonin is the hormone responsible for controlling our sleep-wake cycles.
2. Too much alcohol (or alcohol too close to bedtime) can cause the sleep phases to become disjointed, so even if we get our usual hours of sleep we are unable to get the quality of sleep we need.
3. Not eating enough calories, or for some people, enough carbohydrate, can lead to blood sugar drops in the evening, raising our stress hormones and causing us to wake up in the early hours of the morning. Conversely, a high load of highly refined carbohydrate food in the absence of fat and/or protein can have the same blood sugar lowering effect.
4. Low levels of iron in the body reduce the amount of iron available for brain function, leading to restless leg syndrome and sleepless nights.
5. Hormone imbalance, specifically hot flashes that occur during perimenopause and menopause.
How to optimise sleep
1. Finish work early enough to allow your brain to unwind and disengage from the stress of the day. Keep a to-do list for action points for the next day to help reduce stress associated with work.
2. Install f.lux on your computer. This free programme pulls blue light out of your computer screen at sunset. Nighshift is an iPhone app that does the same thing for your devices. Consider buying blue light-blocking glasses and wearing them in the three hours before bed. These can block up to 80 per cent of blue light from the environment.
3. Disengage from social media or other activities that may make it difficult to relax.
4. Avoid alcohol 3-4 hours before bedtime and practise appropriate drinking behaviour.
5. Ensure your evening meal is balanced with enough calories coming from fat and protein to avoid blood sugar crashes in the middle of the night.
6. If you suffer from restless leg syndrome, get your iron levels checked and correct if necessary.
7. Glycine, an amino acid found in the gelatinous part of meat (or in a good quality gelatin product such as Nutra-Organics), helps cool body temperature and may aid in sleep.
8. Magnesium supplementation can be very effective for people who have difficulty unwinding and falling asleep. A supplement that contains at least 200mg elemental magnesium in a complex that incorporates amino acids or glycinate is better absorbed than a magnesium oxide complex.