Staying safe in the sun: how some medications can affect your body’s ability to keep cool 

Posted July 30th 2026

The record-breaking temperatures and frequent heatwaves experienced in recent years are becoming an increasingly familiar part of our summers. For people taking medication, it is especially important to stay safe in the sun.

The record-breaking temperatures and frequent heatwaves experienced in recent years are becoming an increasingly familiar part of our summers.

While many people enjoy warmer weather (and are happy to have a break from the rain), prolonged periods of heat can become uncomfortable and, in some cases, pose health risks.

Hot weather can disrupt sleep, affect daily activities and place additional strain on the body.

One important consideration is that some medications, used for our mental and physical health, can affect the body’s ability to regulate its temperature in hot weather.

This process, known as thermoregulation, helps maintain a stable body temperature through a combination of brain function, hormones, the nervous system and sweating, which allows the body to cool itself.

Medications and keeping cool

Certain medications may interfere with this natural cooling process. These include some antidepressants, antipsychotics, mood stabilisers, benzodiazepines and ADHD medications, as well as medicines used to treat a range of physical health conditions, including heart disease, diabetes, antibiotics, infections and allergies.

These medications can affect thermoregulation in different ways, such as increasing heat production, reducing sweating or altering the body’s normal cooling mechanisms. As a result, some people may be more vulnerable to overheating, particularly during periods of very hot weather.

The effects of these medications vary from person to person, and some groups, such as older adults, may be more susceptible than others.

However, you should not stop taking your prescribed medication because of hot weather. If you have any concerns about how your medication may affect you during periods of high temperatures, speak to your GP, pharmacist or healthcare team before making any changes. 

Recognising the signs of overheating

It’s important to recognise the early signs that your body may be struggling to cool itself.

Symptoms can include:

• feeling dizzy or lightheaded

• headaches

• muscle cramps

• a rapid heartbeat

• feeling unusually tired or weak

• nausea or vomiting

If you experience these symptoms, move to a cooler place, drink water and take steps to lower your body temperature. If symptoms become severe or do not improve, seek medical advice promptly.

Staying safe during hot weather

There are several simple steps you can take to prevent and reduce the risk of overheating:

• use sunscreen and wear a hat or use an umbrella to protect yourself from direct sunlight

• avoid spending prolonged periods in direct sun and stay in the shade where possible

• avoid strenuous exercise during the hottest part of the day

• drink plenty of water to stay hydrated, particularly if you take lithium

• limit alcohol and caffeinated drinks, as they can contribute to dehydration

• wear lightweight, loose-fitting clothing

• use cool showers, baths or damp cloths to help lower your body temperature

• prevent constipation by staying well hydrated and follow your healthcare professional’s advice for managing your symptoms – which may include laxatives

As our summers become warmer, understanding how heat can affect both our bodies and the medications we take is increasingly important.

By recognising the signs of overheating, staying hydrated and taking simple precautions, you can continue to enjoy the warmer weather while helping to protect your health.

We would like to thank Tegan Conway and Fiona Cule for their assistance in producing the original “Staying Safe in the Sun” leaflet.

Resources

• Download our new staying safe in the sun – A4 poster
  NCMH sun safety A4 poster (2026 – Eng)Created by NCMH and Cardiff and Vale University Health Board.