It's well known that jet lag, shift work, sleep disorders and so on can all affect the body's internal clock, but can everyday lifestyle choices also make it difficult to listen to what the body is trying to say? Humans have the ability to override the body's internal clock - it's part of a built-in defence mechanism - but many people abuse this power, ignoring the ticking and working to their own schedule. Here's how to regain that natural rhythm …
Eating too close to the body's natural bedtime could prolong daytime rhythms within the 24-hour cycle, encouraging the body to remain active and alert long past lights out. Carbohydrates, sugars, and proteins (essentially anything that isn't pure fat) cause peaks in blood sugar, stimulating the pancreas and promoting the production of insulin and energy. [i]This is why it's so important to eat breakfast - it pushes the body to release the energy needed to begin the day. However, this sort of surge in insulin at night makes the body think it needs to expend this energy, meaning it's more difficult to listen to your body clock telling you to rest.
Studies have found that exercising during the day can make it easier to listen to your body clock, encouraging better sleeping habits and overall promoting a higher quality of sleep. Exercise can reduce the amount of rapid eye movement (REM) sleep during the night by up to five minutes, according to research. [ii]REM sleep is when there's definite activity and energy in the brain (this is when you dream), while deep sleep is when the body is relaxed, and when it restores, heals, and rejuvenates itself - deep sleep is essential for a good night's rest. What's more, exercise delays the onset of REM sleep, making sure the body rests when it really needs it.
The internal body clock is regulated by the differing light levels during the day and night, and it's the hormone melatonin that helps to regulate this cycle, telling the body to rest when it's darker, and encouraging it to be more active during the lighter hours. When it's light outside, melatonin concentrations in the body are suppressed, and are greater when it's dark. Using technology in bed - such as mobile phones, tablet PCs, or backlit e-readers - anything that produces light - minimises melatonin levels and makes the body think that it's daytime. [iii]Naturally, the body wants to be active during the day, which can make it challenging to listen to what your body's saying.
The question is - why is it so important to listen to the internal body clock? "Chronic desynchronisation between physiological and environmental rhythms not only decreases physiological performance but also carries a significant risk of diverse disorders such as diabetes, cardiovascular diseases, sleep disorders, and cancer", according to researchers.[iv]
[i] Sheard, Nancy F. et al. "Dietary Carbohydrate (Amount and Type) in the Prevention and Management of Diabetes". Diabetes Care, September 2004, vol. 27
[ii] Driver, Helen S. and Taylor, Sheila R. "Exercise and Sleep". Sleep Medicine Reviews, Volume 4, Issue 4, August 2000, Pages 387-402
[iii] Figueiro MG et al. "The impact of light from computer monitors on melatonin levels in college students". Neuro Endocrinology Letters, 2011
[iv] Miho Sato et al. "The Role of the Endocrine System in Feeding-Induced Tissue-Specific Circadian Entrainment". Cell Reports, Volume 8, Issue 2, 24 July 2014, Pages 393-401