How Do The Changing Clocks Affect Your Health?

How do the changing clocks affect your health?

When do the clocks change?

Every year, on the last Sunday of March, the clocks move forward by an hour which signals the start of British Summer Time. This year the clocks go forward on 26th March at 1am in the UK.

The main question everyone asks is ‘does that mean I get an extra hour in bed?’. Unfortunately, this time you lose an hour.

Why do the clocks change?

So why do we change the clocks twice a year, surely it’d be simpler to keep them the same all year round? It all started because of a campaign at the beginning of the 20th century to allow people in the northern hemisphere to make more use of the earlier daylight hours.

There have been increasing calls to scrap changing the clocks due to health concerns linked to the time change. Some studies have shown it disrupts the body’s natural sleep cycles which can have a knock-on effect both physically and mentally.

Changing Clock

How does changing the clocks impact my physical health?

Your brain has a biological clock, also known as your Circadian Rhythm, that runs on a 24-hour cycle. No matter if you’re gaining or losing the hour, some people find it harder than others to adjust to this new schedule. It might only be and hour, but that’s all it takes for your own internal body clock to fall out of sync. While this only happens twice annually, disturbed sleep can also potentially lead to an increased risk of cardiovascular disease.

Researchers at Harvard Medical School and the Massachusetts General Hospital carried out a study comparing the impact of sleep deficiency on heart disease in mice. After 16 weeks, mice who were subjected to disrupted sleep cycles developed larger arterial plaques than those with normal sleeping patterns. The sleep deficient mice also had twice the level of white blood cells in their circulation and lower levels of hypocretin, a hormone that aids with the regulation of sleep and wake states.

How does changing the clock impact my mental health?

In Autumn when the clocks go back, we gain an extra hour of daylight in the morning. This only lasts a couple of weeks before the days shorten, and the sunrise gets later again.

By the time the shortest day of the year comes around, the UK enjoys less than eight hours of sunlight each day.

This increase in darkness can result in low mood and depression for some, as well as fatigue, muscle pain and weakened bones due to a lack of vitamin D, which we get from sunlight exposure. Seasonal Affective Disorder (SAD) can also affect people because of the shorter days. According to the NHS, SAD can present itself as a persistent low mood, loss of pleasure or interest from normal daily activities, irritability, feelings of despair or guilty, and sleeping for longer than usual. Links have also been made between sunlight and the performance of the hypothalamus, with decreased sunlight exposure causing a decrease in function. The hypothalamus is responsible for managing your body temperature, hunger, thirst, mood, blood pressure and sleep.


While it means we get to make the most of the extra daylight hours moving into summer, just remember it could take a day or two till your body adapts to its new routine. In the week leading up to the clock change, moving your bedtime earlier by 10-20 minutes could help you adjust quicker. Most of the extremes we have mentioned are related to more prolonged sleep disruption, and for most people it’ll just mean getting up on Monday morning is a little harder than your typical Monday!