If you’re travelling on the Tube this summer, you’re probably already hot, sweaty and miserable. But if you’re on antidepressants, you might also be at risk of overheating.
The hottest temperature ever recorded on the London Underground is up for debate.
TfL’s official statistics recorded 33.1C on the Victoria Line in August 2024. Ask any commuter down there during a heatwave, however, and they’ll tell you it feels more like the burning gates of hell.
Selective Serotonin Reuptake Inhibitors (SSRIs), used to treat anxiety, depression and panic disorders, are generally considered safe and effective. But they come with a major side effect that’s often overlooked: heat intolerance.
These common medications can affect the body’s ability to regulate temperature, putting people at higher risk of heat exhaustion, especially in sweltering environments like the London Underground.
Last year, more than 8.7 million adults were prescribed antidepressants, according to NHS data. Social media is filled with thousands of people’s experiences with them, good and bad. And one common complaint in summer is the heat.
Some have said they’ve been ‘melting’ and ‘overheating’, while temperatures have been hitting 30C, while others compare it to being ‘burnt alive’.
‘Taking antidepressants doesn’t mean you can’t enjoy summer, but it does mean you mean you need to be extra cautious during extreme heat,’ Dr Asim Cheema, an internal Medicine and Cardiology specialist at Your Doctors Online, tells Metro.
Dr Cheema explains that certain antidepressants, including SSRIs, tricyclic antidepressants, and SNRIs (Serotonin-Norepinephrine Reuptake Inhibitors), can impair the body’s ability to regulate temperature.
‘Some affect the hypothalamus (which controls temperature regulation), while others reduce sweating, making it harder for the body to cool down naturally,’ he explains.
‘This can increase the risk of heat exhaustion, dehydration, and even heatstroke during periods of high temperature.’
Dr Cheema says this can occur when taking commonly prescribed SSRIs, like Sertraline and Fluoxetine, SNRIs, like Venlafaxine and Duloxetine, as well as tricyclic antidepressants, like amitriptyline.
‘Antipsychotics, beta blockers, diuretics and some antihistamines can also affect heat tolerance,’ he adds.
If you’re travelling to work on sweltering public transport, spending most of the day outside, or just trying to enjoy the sun, there are some common signs of heat exhaustion to look out for.
Dr Nikita Kanani, Chief Strategy and Innovation Officer at Aneira Health, tells Metro, this can include dizziness, nausea and heavy sweating.
Dr Kanani advises ‘acting quickly’ if you spot any of these symptoms. He suggests moving to a cooler place, sipping water slowly and using a fan or a damp cloth to cool down.
He adds: ‘Avoid pushing through your symptoms, listen to your body and importantly, talk to your doctor if symptoms persist – you may need to adjust when you take your medication or review alternatives.’
To protect yourselves during the heat, he suggests avoiding direct sun exposure during the hottest part of the day (between 11am and 3pm). ‘If you’re out, wear a hat, use SPF, and take breaks in the shade. Planning outdoor time for early morning or evening can help reduce risk.’
And for those braving sweltering public transport, he advises planning ahead where possible. ‘Travel outside peak times, carry water, wear breathable clothing, and use a hand fan.
‘If you feel faint or unwell, get off at the next stop, find somewhere cool, and rest. Never ignore symptoms – overheating can happen quickly.’
Dr Kanani adds that while common, this side effect can often be overlooked and isn’t routinely discussed.
He adds: ‘Especially when medications are first prescribed in the cooler months or if someone is starting treatment for the first time. It can also be underestimated in clinical consultations, where the focus is understandably on mental health support.
‘As heatwaves become more common, we need to talk more openly about how medication affects our health in real-world conditions – especially for women and people with long-term conditions.’
How to take precautions during hot weather on public transport
If you’re taking antidepressants or any medication that makes you more susceptible to heat, Dr Asim Cheema advises the following:
- Recognise warning signs: Headache, nausea, confusion, or feeling faint can all signal heat-related distress, which is more likely if you’re on certain medications.
- Stay well-hydrated: Dehydration can worsen side effects like dizziness or lightheadedness.
- Dress lightly: Wear breathable, loose-fitting clothes.
- Plan ahead: If you know you’ll be on the Tube or in another hot environment, carry water, use cooling towels, and if possible, avoid peak travel times.
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