However, extreme heat can have a significant impact on mental health. While some people experience mood improvements and increased social activity during warm weather, others may notice heightened anxiety, irritability, poor sleep, and worsening symptoms of existing mental health conditions. For individuals taking antidepressants such as Selective Serotonin Reuptake Inhibitors (SSRIs), the effects of extreme heat can be particularly important to understand.

The Positive Effects of Warm Weather on Mental Health

For many people, sunshine and warmer temperatures can provide genuine psychological benefits.

Improved Mood

Exposure to sunlight can increase the body's production of serotonin, a neurotransmitter associated with feelings of wellbeing and happiness. Higher serotonin levels are often linked to improved mood, greater motivation, and increased energy.

Increased Social Connection

Warm weather encourages outdoor activities, social gatherings, and physical exercise. Spending time with friends and family can reduce feelings of loneliness and isolation, both of which are closely linked to anxiety and depression.

More Physical Activity

People are often more active during periods of good weather. Exercise is known to reduce stress hormones while promoting the release of endorphins, helping to improve mood and reduce anxiety symptoms.

Temporary Relief from Seasonal Mood Challenges

Many individuals who struggle with low mood during darker months report feeling more positive, motivated, and energised during sunny weather.

The Negative Impact of Extreme Heat on Mental Health

While moderate warmth may be beneficial, temperatures approaching 38°C can place significant strain on both the body and mind.

Increased Anxiety and Stress

Heat places the body under physical stress. As temperatures rise, heart rate increases, sweating intensifies, and breathing may become faster. These physical sensations can closely resemble symptoms of anxiety or panic attacks.

For individuals who already experience anxiety, the body's response to heat may trigger anxious thoughts such as:

• "Something feels wrong."
• "Why is my heart racing?"
• "Am I becoming unwell?"

This can create a cycle where physical discomfort fuels psychological distress.

Poor Sleep Quality

One of the most common consequences of a heatwave is disrupted sleep.

The body naturally needs to cool down before sleep. During very hot nights, this process becomes more difficult, leading to:

• Difficulty falling asleep
• Frequent waking during the night
• Reduced deep sleep
• Increased daytime fatigue

Even a few nights of poor sleep can significantly worsen anxiety, stress levels, mood regulation, and emotional resilience.

Irritability and Reduced Emotional Control

Research consistently shows that high temperatures can increase irritability, frustration, and emotional reactivity. People may find themselves becoming more impatient, short-tempered, or overwhelmed by situations they would normally handle well.

For those already managing anxiety disorders, depression, or stress-related conditions, this can make symptoms feel more intense.

Worsening Symptoms of Existing Mental Health Conditions

Extreme heat can worsen symptoms associated with:

• Anxiety disorders
• Depression
• Bipolar disorder
• Obsessive-compulsive disorder (OCD)
• Post-traumatic stress disorder (PTSD)

Many mental health professionals observe increased psychological distress during prolonged heatwaves, particularly when temperatures remain high overnight.

SSRIs and Heatwaves: What You Should Know

Selective Serotonin Reuptake Inhibitors (SSRIs) are among the most commonly prescribed medications for anxiety disorders, depression, obsessive-compulsive disorder, and other mental health conditions.

While SSRIs are generally safe during hot weather, there are several important considerations during periods of extreme heat.

Increased Risk of Dehydration

One of the most significant concerns is dehydration.

Heatwaves increase fluid loss through sweating. Dehydration can contribute to symptoms that may overlap with anxiety, including:

• Dizziness
• Rapid heartbeat
• Fatigue
• Headaches
• Difficulty concentrating
• Feeling faint

When these symptoms occur, some individuals may mistakenly believe their anxiety is worsening when dehydration is actually playing a role.

Potential Effects on Temperature Regulation

Some antidepressants, including SSRIs, may affect the body's ability to regulate temperature efficiently in certain individuals. Additionally, some people taking SSRIs report increased sweating, which can contribute to fluid loss during periods of extreme heat.

This does not mean people should stop taking their medication during hot weather. In fact, suddenly discontinuing an SSRI can lead to withdrawal symptoms and a worsening of mental health symptoms.

Instead, individuals should:

• Stay well hydrated
• Avoid prolonged exposure to direct sunlight
• Take breaks in cool environments
• Monitor for signs of heat exhaustion

Anxiety About Physical Symptoms

Many people taking SSRIs for anxiety are highly aware of bodily sensations.

During a heatwave, symptoms such as sweating, dizziness, increased heart rate, and fatigue can be misinterpreted as signs of worsening anxiety or panic. Understanding that these can also be normal responses to extreme heat may help reduce unnecessary worry.

Maintaining Medication Routines

Hot weather can disrupt daily routines, sleep schedules, and eating habits. However, it remains important to continue taking prescribed medication as directed and to seek professional advice before making any changes.

Protecting Your Mental Health During a Heatwave

When temperatures reach 38°C, mental wellbeing requires the same attention as physical health.

Helpful strategies include:

Stay Hydrated

Drink water regularly throughout the day, even if you do not feel thirsty.

Prioritise Sleep

Keep bedrooms as cool as possible by:

• Closing curtains and blinds during the day
• Opening windows when temperatures fall in the evening
• Using fans where appropriate
• Taking a cool shower before bed

Reduce Overstimulation

If heat is increasing anxiety or irritability, consider:

• Spending time in shaded or air-conditioned environments
• Limiting strenuous activities during the hottest hours
• Taking regular breaks throughout the day

Continue Prescribed Medication

Take medications as prescribed and speak with a healthcare professional if you have concerns about how heat may affect you.

Check in With Yourself

Heat can make emotional reactions feel stronger. If you notice increased anxiety, low mood, irritability, or exhaustion, remind yourself that the weather may be contributing to how you feel.

Final Thoughts

A 38°C heatwave in the UK can bring both benefits and challenges for mental health. While sunshine and longer days may improve mood, extreme temperatures can also increase anxiety, disrupt sleep, worsen emotional regulation, and intensify existing mental health conditions.

For people taking SSRIs, the combination of heat, dehydration, and anxiety-like physical symptoms can sometimes create additional challenges. Staying hydrated, maintaining medication routines, prioritising sleep, and recognising the effects of heat on the body can help protect both physical and mental wellbeing during periods of extreme weather.

As climate change increases the frequency and intensity of heatwaves across the UK, understanding the relationship between temperature and mental health is becoming increasingly important. By recognising both the positive and negative effects of extreme heat, individuals can take practical steps to support their wellbeing during the hottest days of the year.