What is your internal body clock?
Your internal body clock, sometimes known as your circadian body clock, is primarily controlled by a part of your brain referred to as the Superchiasmatic Nucleus (SCN), a collection of cells that inhabit your hypothalamus.
Simply put, this internal clock helps to govern your sleep-wake cycle ensuring that melatonin, the sleep hormone, is released as daylight recedes and that cortisol, a stress hormone, is secreted before you wake up in the morning. However, it is possible to disrupt this internal clock – jet lag is one particularly famous way of upsetting your sleep patterns while in recent years, shift work has emerged as another prime example.
I’m sure you’re all familiar with the effects that can follow upsetting your biological clock – you’re more likely to feel groggy, more prone to lapses in memory and concentration and can you may notice that you feel more sensitive to stress. In the short-term, your biological clock can recover but if these disruptions become chronic it can present a number of health problems, such as weakening your immune system and even contributing to the development of cardiac diseases.1
However, recent research is now taking a more in depth look at how your internal clock may affect your mood. Often, sleep disorders are seen as an inevitable symptom of mental health problems such as depression but now experts are saying that the reverse may also be true, with disruptions to your internal clock making you more predisposed to developing a mood disorder.
The Lancet study
The study published in Lancet Psychiatry involved around 91105 participants from across the UK Biobank, within the age range of 37-73. These participants were then monitored to measure their activity levels as each was required to wear an accelerometer for 7 days. Those who were extremely active at night but not as active during the day were classified as having disrupted biological clocks and were 6-10% more likely to have been diagnosed with a mood disorder.2
This seems to hint that there is an underlying relationship between your circadian clock and mental health disorders. Although further study may be needed, preferably with a younger age range as most mental health disorders develop before the age of 24, it’s still interesting to consider and would tie into a lot of what we’ve already discussed about the connection between sleep deprivation, stress and anxiety.
One of the researchers attached to the study, Professor Daniel Smith, also mentioned something very telling in an interview with BBC 4 radio, citing that it was ‘likely’ that some people in the study who experienced disruptions may be using social media at night.3
If you’ve read any of my blogs, you’ll know I’ve never been a massive fan of staying up all night browsing social media or using any electronic devices in bed. The blue light emitted from your tablets, smartphones and laptops is infamous for interrupting your production of melatonin and sometimes even stimulating stress, so it’s nice to see that the issue is getting some recognition too!
What can we learn from this study?
Sleep and mood have always been intricately connected but it is interesting to learn that it isn’t an entirely one-sided relationship, and it’s important to bear this in mind when it comes to our attitude towards sleep. I’ll be very curious about further studies conducted on younger age groups, who are largely, more exposed to factors such as social media, smartphones etc.
In the meantime, I think it’s important to try and maintain a consistent sleep pattern to avoid irregularities such as social jet lag, which can upset your internal circadian clock. I talk a bit more about your circadian rhythm in my blog ‘What is your circadian rhythm?’ which does address a few of the key factors than can disturb your circadian clock.
If you’re interested in some of my other blogs that cover the relationship between sleep and your mood, please check out a few of the links below!
The differences between night owls and morning larks
Is a good night’s sleep the key to happiness?
Don’t let poor sleep drag you down
Can sleep deprivation affect your self-esteem?
1https://www.sciencedirect.com/science/article/pii/S0914508711000487
2https://www.thelancet.com/journals/lanpsy/article/PIIS2215-0366(18)30139-1/fulltext
