Rainy day depression: why does our mood change over time?


June usually marks the start of the alfresco dining, alfresco pub and picnic season, but parasols have been the accessory of choice for many people across the UK over recent rainy days.

The ever-changing weather we've experienced so far this summer has made layering essential and people's moods often tend to reflect the gray, gloomy skies.

Many theories have been proposed about how the weather affects our mood, energy, and mental functioning.

Mental health experts have unraveled the biology behind the “rainy day blues,” offering helpful tips on how we can rediscover that summer energy during the recurring rain showers that dominate the weather.

How does the weather affect our mood?

Antonio Kalentzis, psychologist and committee member of the British Psychological Society, explained that the weather significantly impacts our mood and mental health through various biological mechanisms such as serotonin production and our sleep/wake cycle.

Kalentzis said: “Sunlight increases serotonin levels, which improves our mood and promotes feelings of well-being.

“On the contrary, cloudy or rainy days can cause a reduction in serotonin production, causing feelings of sadness or lethargy.

“In addition, exposure to natural light regulates our circadian rhythms, influences our sleep patterns and our overall mental health.”

Meanwhile, London-based psychologist Barbara Santini expressed the importance of vitamin D in our mood and brain function.

Santini said: “The role of vitamin D, synthesized in the skin through exposure to sunlight, also cannot be underestimated.

“It supports brain health and function, and deficiencies can be linked to depressive symptoms.

“During rainy seasons, when exposure to sunlight is minimized, vitamin D production can decrease, which can exacerbate feelings of depression or fatigue.”

In addition, Dr. Laura Geige, physician and psychologist, stated that tumultuous and dark clouds also affect the hormone that regulates sleep, so they can cause fatigue.

She said: “On darker days, the body produces more melatonin, the hormone that regulates sleep.

“High levels of melatonin during the day can cause drowsiness and fatigue.”

What negative impact can this have on our daily lives?

Santini explains that, from a psychological perspective, the weather can influence people's willingness to engage in activities that can affect their mental health.

For example, gray and gloomy skies often force people to remain confined indoors, while sunlight often increases enthusiasm for outdoor activities, which has a positive impact on our energy and serotonin levels.

Seasonal affective disorder (SAD), defined by the NHS as a type of depression that comes and goes in a seasonal pattern, is a notable condition that can be triggered by periods of bad weather.

According to Nuffield Health, symptoms of SAD include low mood, anxiety, stress, and increased levels of fatigue.

In more severe cases, SAD can cause increased levels of aggression, insomnia, headaches, reduced appetite, and mental confusion.

Additionally, Kalentzis said rising temperatures can also trigger mood episodes, especially in people with specific mental health conditions, such as bipolar disorder.

“Elevated temperatures can induce manic episodes due to physiological stress and sleep disturbances caused by heat.

“High temperatures can also lead to dehydration, increased irritability and anxiety, exacerbating existing mental health problems,” Kalentzis explained.

What can we do to mitigate these negative impacts?

We may not be able to stop the coming downpours and summon bright blue skies, but mental health experts have proposed a variety of lifestyle changes and tricks we can easily implement into our daily lives to protect ourselves from the blues of the rainy days.

All the experts we spoke to recommended regular physical exercise to increase energy levels and improve mood.

They were also unanimous in encouraging people to go out and expose themselves to the sun as much as possible, even on cloudy days, or to opt for light exposure therapy.

Geige said: “Using phototherapy lamps simulates exposure to sunlight, which can help regulate serotonin and melatonin levels.

“Regular physical activity, a balanced diet and adequate sleep are also vital to maintaining energy and mood.

“Stay connected and participate in social activities, even if they are indoors or virtual, to combat feelings of isolation.”

Kalentzis also urged anyone experiencing persistent symptoms of SAD to contact their local GP.

He said: “If you need help, don't hesitate to ask.

“Seeking support from friends, family, or mental health professionals is a sign of strength.

“Keep a positive attitude, be aware of your needs and prioritize your mental well-being regardless of the weather outside.”

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