The clock is ticking! Circadian rhythms and their control of sleep during ageing

Many functions in the body are controlled by natural cycles that tend to last 24 hours. These cycles are known as circadian rhythms. A small hypothalamic nucleus located deep in the brain, the suprachiasmatic nucleus, performs a fine-grained control of our internal rhythms.

An orchestra director in our head

One way of imagining the suprachiasmatic nucleus is to think of it as an orchestra director. The suprachiasmatic nucleus synchronises the circadian rhythms of many different organs in the body, including the liver, the heart, and the muscles. By using endocrine and neural communication, it orchestrates different peripheral internal clocks, having an impact on functions that can be as diverse as the regulation of body temperature, feeding behaviours, sleeping, or exercising.

Hormonal levels show well-defined circadian rhythms

In humans, the levels of some hormones such as cortisol, insulin, and ghrelin are higher in the morning and in the afternoon. Others, like melatonin, leptin, or growth hormone peak sometime in the evening or at night. These daily fluctuations have implications for feeding and sleeping behaviours, and alterations in these natural rhythms might underlie some changes in food intake and sleep that are associated with ageing.

Ageing affects many functions in the body, including circadian rhythms

With ageing, the circadian rhythms modulating body temperature and hormonal levels, specifically regarding cortisol and melatonin, become shallower, losing amplitude, and potentially altering internal rhythms, such as sleeping patterns. In fact, sleep undergoes many changes as we age. Compared to younger adults, older adults need more time to fall asleep, sleep for a shorter time, wake up more often, and spend less time in slow-wave stages of sleep. Some interventions that improve circadian rhythms can also help with sleep problems in ageing.

One of the strategies to improve functions associated with circadian rhythms is physical activity

Physical exercise has well-known beneficial effects for longevity, cardiovascular health, cognitive function, and sleep patterns. More specifically with regards to sleep, exercise has been proposed as a method to ameliorate sleep alterations in ageing. In elderly people, morning exercise seems to restore slow-wave activity during sleep, resembling the levels shown by younger people. Other studies have found that physical exercise improves subjective sleep quality and shortens the time needed to fall asleep.

A question that arises then is, how much exercise do you need to do in order to feel its health benefits in ageing? Probably not as much as you think. A recent study has shown that for people aged 60 years or older, walking between 6000 and 8000 steps a day confers around a 40% to 50% reduction in their risk of death.

Another strategy to improve sleep is nutrition and food supplements

The evening Holistic Health REST AND RESET formula uses the strengths of many ingredients. The patented Bluenesse® , derived from Lemon Balm Melissa officinalis, is known to contribute to reinforce biological sleep-wake cycles. L-Tryptophan is recognized to boost the production of the chemical serotonin, which influences sleep and mood. Passionflower and Valerian extracts are known to help relieve anxiety and sleep disorders. Vitamin B6, Niacin, Magnesium and the Holistic Complex complete the formula.

Circadian rhythms control many important functions of the body, and suffer certain changes with ageing. With a healthier lifestyle, we can support the health of our internal circadian clocks and walk towards a healthier, fuller path.