Circadian rhythm and sleep disturbances

The lives of most living creatures, including humans, are regulated by the predictable rhythm of night and day which is known as Circadian Rhythm. Circadian rhythm influences our body’s physiological functions such as core body temperature, hormonal secretions, heart rate, renal output, and gut motility. When the circadian rhythms are out of harmony with the day-night cycle, people can not only experience sleep disturbances but also other health problems.

What is circadian rhythm?

Our circadian “clock”, is regulated by a set of genes that operate through a series of feedback mechanisms with a regular cycle of about 24 hours.

The circadian clock governs the rhythmic changes in metabolism and psychological activity, ensuring that our body is attuned to the level of mental and physical activity associated with a particular time of day or night. Mental ability and energy levels are highest during the daytime. However, during the night, when we are no longer active, core body temperature falls. At the same time, cortisol levels rise before waking. With hormonal release, there are cyclic changes in the level of sleep.

When the sleep cycle is out of sync

The sleep cycle be disrupted and thrown out of sync by disturbances to the day-night cycle. Changes in light can disrupt our sleep cycle as it delays circadian rhythms. Factors that disrupt sleeping patterns such as Jet-lag and shift work can also disrupt the clock.1 When the times of going to sleep and waking up are varied, people are at risk for experiencing dysphoria, poor functioning and increased health risk.

Circadian rhythms can also be affected by patterns of social behaviour such as meal times. If people do not stick to a regular routine of eating in relation to going to bed, they run the risk of disturbing their sleep cycle and developing insomnia. Altering the timing and amount of food intake, disrupting energy balance, increasing inflammation, impairing glucose tolerance, and causing insulin sensitivity, insufficient sleep and sleep disruption can affect metabolic health, contributing to obesity and type 2 diabetes. Poor sleepers have a higher risk of stroke than good sleepers and this is particularly true among people aged 18 to 34 years.

Getting back in sync

Performing routine daily activities at the same time each day is important. Trying to eat dinner and go to bed at the same time can be helpful. Avoiding stress is key. This can be mitigated with regular meditation or clearing.

Understanding how your daily habits affect your body’s functioning and ultimately sleep patterns will allow you to help ease your sleep and function better as an individual providing better quality of life. If you are experiencing continual issues, speak with your pharmacist.


Adam Shakespeare