Being on SSRIs doesn’t mean you have to suffer through the summer, but it does mean you should be extra cautious during high temperatures.
The UK is currently sizzling through an unexpected scorcher, with temperatures creeping up to 32C — and if you’re finding the heat especially unbearable, your antidepressants might be playing a bigger role than you think.
Millions of people across the UK have been prescribed selective serotonin reuptake inhibitors (SSRIs), a class of antidepressants sold under brand names such as Sertraline, Citalopram, Fluoxetine and Mirtazapine. As well as depression, they’re often used to treat anxiety and OCD, among other mental health disorders.
Mental Health UK has warned people taking such medication that ‘summer can be a difficult time’ for users of SSRIs due to increased heat sensitivity.
L360 speaks to experts about the link between SSRIs and hot weather, and what you can do to keep safe this summer.
Read more: 5 best things to do in London in summer 2025: events and pop-ups
How do antidepressants affect you in hot weather?
SSRIs don’t just impact mood — they also influence how your body regulates temperature. That becomes especially important during a heatwave.
“SSRIs can affect the way the body regulates temperature, which is why people taking them may be more sensitive to heat,” explains Sarah Jeffries, paediatric first aid expert and founder of Paediatric First Aid. “These medications influence serotonin, a neurotransmitter involved in many bodily functions, including how the body manages heat and signals thirst.”
Dr Sarah Bonza, a board-certified family medicine physician, adds that increased serotonin levels can affect the hypothalamus — the brain’s internal thermostat.
“SSRIs make the hypothalamus more heat-sensitive, so it can signal that the body is hotter than it really is,” she says. “Normally, your body would respond by sweating to cool down, but SSRIs can impair that response, too. Without effective sweating, your body struggles to get rid of excess heat, increasing the risk of heat exhaustion or heatstroke.”
In short, SSRIs can leave your body confused about how hot it actually is and slow down the very systems meant to keep you cool.
Read more: How to keep cool in the heatwave 
Your body feels hotter than it actually is, with no way of cooling down (Picture: Freepik)
Signs you shouldn’t ignore
According to Sarah, it’s vital to be aware of symptoms like dizziness, headaches and nausea — all of which can intensify in extreme heat.
“If someone feels faint or confused, or stops sweating altogether, that’s a medical emergency,” she warns.
The best course of action in this situation is to get them out of the heat immediately, sit or lie them down, give them water and call 111.
How to stay safe
If you’re on SSRIs, the most important thing you can do is stay ahead of the heat. Sarah recommends:
- Hydrating regularly, even if you don’t feel thirsty
- Avoiding intense exercise during the hottest parts of the day
- Staying indoors or in the shade when temperatures peak
- Taking cold baths or showers to cool body temperature
And don’t be tempted to make any changes to your medication without professional guidance. “If you’re struggling with the heat, speak to a healthcare professional,” says Sarah. “It’s always better to adjust your environment and habits than to stop treatment abruptly.”
Feature image: Canva
