HEALTHPLAN MAGAZINE

On the last Sunday of October each year, the UK and all countries within the European Union, turn back the clocks by one hour at 2 am. This transition marks the start of shorter days and longer dark nights.

This adjustment provides us with an extra hour of sleep as we prepare for the colder winter months. While the additional hour of sleep is often welcomed, the practice of changing the clocks twice a year remains quite controversial.

Back in 2019, the European Parliament voted to eliminate the practice of changing clocks after a study found that 84 percent of people in countries participating in daylight saving time wanted to discontinue it. However, in the UK, a YouGov poll showed that a majority of Britons were marginally in favour of keeping the current system, with 44 percent voting to retain it and 39 percent voting to scrap it.

There are also health concerns associated with the time change, as numerous studies have shown that it can disrupt the body's natural sleep cycles, impacting both physical and mental health. So, what is the impact of turning back the clocks on our health?

The impact on our physical health

According to the Mayo Clinic, the human brain operates on a 24-hour biological clock, also known as a circadian rhythm. Circadian rhythms play a crucial role in regulating various bodily processes, including our sleep-wake patterns, appetite, and body temperature. These rhythms essentially act as the body's internal clock, synchronising with the day-night cycle to guide our sleep and wake times. Significantly, our circadian rhythm relies heavily on external cues, primarily light and darkness. Light signals wakefulness, while darkness signals sleepiness.

The shift to winter time disrupts our sun exposure schedule, causing an imbalance in our internal clock, which can require several days to reset. This adjustment impacts our bodies, particularly during the initial three or four days, resulting in common symptoms like drowsiness, a degree of irritability due to reduced afternoon daylight, reduced concentration, or occasional insomnia. It's worth noting that these are generally mild disruptions rather than severe disorders.

In a statement, The Spanish Sleep Society ( SES ) also recognises that “the time change, even if it is only one hour, alters the time of exposure to the sun and unbalances the internal clock, which takes several days to readjust.” These changes cause, according to the organisation, “insufficient, disorganised and poor quality sleep” which, in some cases, can lead to diseases such as obesity, high blood pressure, depression or anxiety.

A 2019 study by researchers at Harvard Medical School and the Massachusetts General Hospital investigated the impact of sleep deficiency on heart disease in mice. It revealed that mice with disrupted sleep patterns developed larger arterial plaques after 16 weeks compared to mice with normal sleep patterns. The sleep-deficient mice also had elevated levels of certain white blood cells and lower amounts of hypocretin, a hormone that regulates sleep and wake states.

This study represents a significant step in demonstrating the molecular connections between sleep health and cardiovascular risk factors. Dr. Michael Twery, director of the National Heart, Lung, and Blood Institute's National Center on Sleep Disorders Research in the US, stated that it is the most direct demonstration yet.

Additionally, losing an hour of sleep during the springtime change has been associated with a surge in heart attacks and strokes. In the US, hospitals report a 24 percent increase in heart attack visits every year on the Monday following the "spring forward" time change. Research has also shown an increase in car accidents when the clocks go back in the colder months, as drivers adapt to the time change. Zurich Insurance data indicates that accidents are more likely to occur between 4 pm and 7 pm in November, as the evenings grow darker earlier.

The impact on our mental health

When the clocks “fall back” in the autumn, we gain an extra hour of daylight in the morning. However, this only lasts for a couple of weeks before the days shorten, and the sunrise becomes progressively later. On the shortest day of the year (winter solstice), December 22, Spain will have approximately 6 hours less daylight than the June solstice.

The increased hours of darkness can result in low mood and depression in some people, along with symptoms such as fatigue, muscle pain, and weakened bones due to a lack of vitamin D from sunlight exposure. Some individuals may experience Seasonal Affective Disorder (SAD) as a result of the shorter days. SAD symptoms include a persistent low mood, loss of pleasure or interest in everyday activities, irritability, feelings of despair or guilt, and longer-than-normal sleep.

The UK’s National Health Service (NHS) notes that the lack of sunlight may disrupt the proper functioning of the hypothalamus in the brain, which can affect the production of melatonin (a sleep hormone) and serotonin (a mood hormone), as well as the body's circadian rhythm.

What can you do to help manage the impact of the time change?

For a smoother transition, the Spanish Sleep Society suggests following the guidelines below for the period right after the shift to winter time:

• Stick to the new schedule, even if it initially poses challenges. Doing so facilitates the maintenance of the adjusted bedtime and wake-up times. Generally, we experience more restful sleep when melatonin secretion occurs, typically an hour and a half to two hours before bedtime.
• If adapting quickly is difficult, consider a gradual transition by adjusting bedtime by 15 minutes each day until reaching a one-hour shift after four days. Consistency in both bedtime and wake-up time is vital.
• Taking short naps during the initial days can help in delaying the biological clock and keeping alert until the new time slot.
• Increase exposure to natural light and engage in physical activity in the afternoon. Morning light accelerates the body's adaptation and synchronises the biological clock more efficiently, whereas evening light has the opposite effect. Morning light also enhances mood and alertness during the day, contributing to better nighttime sleep.

Disclaimer

The information provided in this article is for educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. It is important to consult with a qualified healthcare professional for personalised guidance regarding your specific health situation. Never disregard professional medical advice or delay seeking it because of something you have read in this article. If you think you may have a medical emergency, call your doctor or emergency services immediately. Always seek the advice of your physician or other qualified health provider with any questions you may have regarding a medical condition. Reliance on the information in this article is solely at your own risk.