It’s the middle of winter and we are currently living in darkness for around 16 hours per day. That should give us plenty of time to squeeze in the recommended eight hours of sleep, right? Whilst we may crave rest and relaxation, sleep can be especially elusive at this time of year. So, what can we do is encourage a good night’s sleep?
- Turn off electronic devices at bedtime. Our circadian rhythm, often referred to as the ‘body clock’ is the 24-hour cycle that tells our bodies when to sleep, wake, and eat. The sleep hormone melatonin plays a significant role in dictating the body’s circadian rhythm. Its production increases with darkness and drops again in light. Studies demonstrate that exposure to electrical light before bedtime suppresses melatonin levels and shortens the body's internal representation of night duration, and can therefore impact sleep (1).
- Be sure to get some daylight. Whilst exposure to light at night-time is not conducive to sleep, being outdoors during the day is important. A lack of light exposure during the day decreases the activity of serotonin, which is a precursor for melatonin. Studies have shown that regular daylight exposure throughout the day can help you get better quality and longer duration of sleep (2) (3).
- Be mindful of what you eat and drink in the evening. Caffeine, alcohol and nicotine are all stimulants and their consumption should be avoided within four hours of going to bed. Choose a sleep-inducing tea such as chamomile or valerian instead. Whilst it is not advisable to eat a main meal close to bedtime, a light snack incorporating foods rich in the amino acid tryptophan which is an essential building block for melatonin production can help you get a good night’s sleep. Good sources are turkey, beans, peanuts, pumpkin and sunflower seeds and bananas. Combine with a wholegrain carbohydrate as this will help tryptophan access the brain and provide magnesium which induces relaxation (4).
- Get the temperature of your bedroom right. Whilst it’s tempting to go to bed with extra layers, a hot water bottle, or even an electric blanket, our core temperature needs to cool to initiate sleep. The optimum temperature is 16-18° C (60-65° F) (5).
- Take a vitamin D supplement. Recent scientific study has found that vitamin D may play a role in improving sleep quality (6). As this vitamin is made primarily by our bodies on exposure to the sun, a lack of sunshine at this time of year can make supplementation a necessity. See our article on vitamin D for more guidance.
Gooley, J. J., Chamberlain, K., Smith, K. A., Khalsa, S. B. S., Rajaratnam, S. M. W., Van Reen, E., Lockley, S. W. (2011). Exposure to Room Light before Bedtime Suppresses Melatonin Onset and Shortens Melatonin Duration in Humans. The Journal of Clinical Endocrinology and Metabolism, 96(3), E463–E472. http://doi.org/10.1210/jc.2010-2098
Boubekri M, Cheung IN, Reid KJ, Wang CH, Zee PC (2014) Impact of windows and daylight exposure on overall health and sleep quality of office workers: a case-control pilot study. J Clin Sleep Med.10(6):603-611. http://jcsm.aasm.org/viewabstract.aspx?pid=29503
Woelders, T. et al., 2017. Daily Light Exposure Patterns Reveal Phase and Period of the Human Circadian Clock. Journal of Biological Rhythms. 32(3), pp.274–286..https://www.ncbi.nlm.nih.gov/pubmed/28452285
Zeng, Y., Yang, J., Du, J., Pu, X., Yang, X., Yang, S., & Yang, T. (2014). Strategies of Functional Foods Promote Sleep in Human Being. Current signal transduction therapy, 9(3), 148-155. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4440346/
The Sleep Council. https://sleepcouncil.org.uk/perfect-sleep-environment/
Evatt M. L. (2015). Vitamin D associations and sleep physiology-promising rays of information. Sleep, 38(2), 171-2. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4288595/