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LIGHT UP YOUR LIFE: You aren’t imagining it, the summer washout could be impacting your mood, here’s why

Last month, the Met Office reported that July was the UK’s sixth wettest on record, and unsurprisingly the UK had 19% fewer hours of sunshine than average over the month, with 140.3 hours in total.

Researchers at the University of Warwick say that light is the most important environmental cue for synchronising our biological clock and regulating sleep, which if interrupted can have a detrimental effect on our mood and wellbeing.

“Our bodies need a balance of both high-energy, or ‘blue’ light, and low-frequency ‘red’ light to function effectively,” says Professor Francesco Cappuccio, from Warwick Medical School at the University of Warwick.

“Blue light is a high-intensity, high-spectrum light, such as the sun. This sort of light signals that it is ‘day’ to our bodies. Red light is a longer wavelength light, and more conducive to sleep or dosing off.”

We already know that we should avoid the bright, blue light emitted from screens at night, so as not to disrupt our sleep, but experts say that when it is gloomy outside, and there is a lack of the high-energy light that our bodies rely on, it is a trigger to our bodies to anticipate sleepiness.

“Similar to what some people may experience during the winter months, it is possible to not get enough of the stimulating ‘blue’ light during the day, particularly if the weather has been cloudy and grey over a longer period of time,” adds Professor Cappuccio.

“This can lead to you feeling fatigued, and sluggish, you may experience a loss of productivity and enthusiasm and feel sleepy a lot of the time.

“Exposure to grey weather over a period of time can also affect your mood. It is subtle and creeping and you may not realise it is happening. In these instances, it is important to try and balance your circadian rhythm by boosting your exposure to light and being active, and maximising the possibility of having a good night’s sleep. This is particularly important to remember as the new season approaches and the days get shorter.”

Sunlight Image by Kireyonok Yuliya on Freepik.jpg

Mood-boosting tips to beat the weather

1. Maximise your exposure to sunlight:

When the weather is fine, it is important to get as much light as possible where we can. This might involve changing your exercise routine to involve outdoor activities or moving your work desk to a nearby window which can also improve your light exposure. “As we head towards the Autumn season and the nights start to draw in, moving our exercise time and social activities to when it is still light outside could help ensure we get enough stimulating blue light during the day,” says Professor Cappuccio.

2. Swap carb-heavy meals for lighter alternatives for your evening meals:

 “Light also affects the way your body metabolises food,” says Prof Cappuccio. “If you are already feeling tired and sluggish, you could find yourself craving carb-heavy comfort food but these foods will only make you feel more tired, as they are harder to metabolise.

“Eating a lighter evening meal that is lower in calories and higher in protein will help you to get better quality sleep.”

3. Prepare for fluctuating temperatures:

 Prof Cappuccio says that temperature is another key environmental cue to ensure a good night’s sleep with the optimum temperature for the bedroom being around 19 degree Celsius, but unpredictable weather can make it difficult to maintain a consistent temperature: “A few lighter layers of bedding could help adjust to a comfortable temperature depending on the weather that night – if it feels particularly cold, you could pull over an extra layer, and remove if you find yourself feeling too warm again.”

4. Improve alertness with exercise:

Rain or shine, keeping active will improve alertness and boost energy levels throughout the day.

5. A dose of Vitamin D

Nutritionist expert, Josh Gibbs at the University of Warwick says: “As the UK faces a gloomy summer, lack of sunshine or blue light can deprive our body of essential vitamins. While there isn't a specific food that can fully replicate the benefits of sunshine, there are certain foods that contain nutrients that can support your health in ways similar to how sunlight does

“Sunshine provides us with vitamin D, which is important for various bodily functions, including mood regulation and bone health. The richest natural sources of vitamin D are all animal-based as vitamin D does not naturally occur in plant-based foods. The richest sources are oily fish, egg yolks, and liver. If choosing these sources, people should make sure they are not consuming over the recommended amount of saturated fat and cholesterol, or their risk of cardiovascular disease could go up.

“The most convenient and effective way for people to hit vitamin D recommendations is to take a vitamin D3 supplement.”

6. Eat mood-boosting blueberries

Dr. Gibbs added: “Blueberries are nutritious and rich in antioxidants and vitamins that can potentially benefit brainBlueberries image by gpointstudio on Freepik.jpg health. Several studies suggest their compounds, like flavonoids and anthocyanins, might positively affect cognitive function, which could indirectly impact mood.

Eating up to 10 servings of fruits and vegetables per day has been correlated with improved psychological well-being, which occurs almost immediately. This is true even when there is adequate sunlight.

“Drinking lots of water and staying hydrated has also been demonstrated to cause immediate improvements in mood, and eating a cup of blueberries has been shown to improve mood within just 2 hours.”


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Notes to editors

Stevens RG. Chapter 15. Loss of sleep or loss of dark? (Answer: both are threats to optimum health). In: Sleep, Health, and Society. From aetiology to public health. Eds: Cappuccio FP, Miller MA, Lockley SW, Rajaratnam SMW. 2nd edition. Oxford University Press, 2018; pp. 133-140.

Cedeño Laurent JG, Allen JG, Spengler JD. Chapter 23. The built environment and sleep. In: Sleep, Health, and Society. From aetiology to public health. Eds: Cappuccio FP, Miller MA, Lockley SW, Rajaratnam SMW. 2nd edition. Oxford University Press, 2018; pp. 206-214.

Lucassen EA et al. Environmental 24-hr cycles are essential for health. Curr Biol 2016; 14: 1843-1853

Thellman KE, et al. Sleep timing is associated with self-reported dietary patterns in 9- to 15-year-olds. Sleep Health 2017; 3: 269-275.

Joshi SS, et al. The importance of temperature and thermoregulation for optimal human sleep. Energy Build. 2016; 131: 153-157.o,mood%3A%20A%20systematic%20review%20of%20randomized%20controlled%20trials