Advice and resources Staying well in hot weather

Overview

Hot weather can cause heat exhaustion which can turn into heatstroke and become a medical emergency.

You are more likely to become ill during hot weather if you:

  • are over 65 years old
  • are 5 years old or younger
  • have a long-term health condition
  • need help to look after yourself
  • have a learning disability, dementia, mental health problems, or a drug or alcohol addiction

It can also be harder to keep cool if you’re in a building that is well-insulated against cold weather, in a city, or has windows that don’t open wide or have blinds or curtains. Being in a room on a higher floor or facing the sun will also make it harder to keep cool.

What is heatstroke?

Heatstroke happens when the body is no longer able to cool down and core temperature exceeds 40ºC despite resting in a cool place and drinking fluids for 30 minutes or longer.

Symptoms of heatstroke include:

  • a very high temperature
  • hot skin that is not sweating and might look red (this can be harder to see on brown and black skin)
  • a fast heartbeat
  • fast breathing or shortness of breath
  • confusion and lack of coordination
  • a seizure or fit
  • loss of consciousness

If you suspect someone has heatstroke, call 999. While you wait for assistance, put them in the recovery position if they have lost consciousness, and continue efforts to cool them down.

You can prevent heatstroke by keeping cool and hydrated and watching for signs of heat exhaustion.

Signs of heat exhaustion and what to do

Heat exhaustion occurs when a person has lost too much water.

Common symptoms include:

  • tiredness
  • weakness
  • feeling faint
  • headache
  • muscle cramps
  • feeling or being sick
  • heavy sweating and intense thirst
  • a core temperature between 38ºC and 40ºC

Take immediate action to cool a person with symptoms of heat exhaustion.

Heat exhaustion does not usually need emergency medical attention if the person cools down within 30 minutes. If action is not taken to cool down, heat exhaustion can lead to heatstroke.

Try the following to cool down:

  • move to a cooler place, such as a room with air conditioning or somewhere in the shade, or cool the room down if it’s not possible to move
  • remove all unnecessary clothing, like jackets or socks
  • drink a rehydration drink or cool water
  • apply cool water by spray or sponge to exposed skin; cold packs wrapped in a cloth and put under the armpits or on the neck can also help

If a person is cooling down and feeling better within 30 minutes, this suggests they are improving. However, if this does not happen, if you are concerned about symptoms, or they are worsening, seek medical advice by contacting NHS 111.

In an emergency, or if you think someone has heatstroke, call 999.

How to keep cool in hot weather

  • Move the most vulnerable people to the coolest rooms (a cool room should ideally be less than 26°C).
  • Avoid physical activity during the hottest time of the day and reschedule exercise and activities like physiotherapy to cooler times of the day.
  • Take regular cool showers, baths, or body washes.
  • Wear light, loose-fitting clothes that absorb sweat and prevent skin irritation.
  • Minimise sun exposure between the hours of 11am and 3pm (when it’s at its strongest).
  • Use sunscreen and follow the guidance on effective use.
  • Sprinkle clothes with water regularly and splash cool water on your face and the backs of your neck.
  • Eat cold food, particularly salads, fruit, and ice-lollies that have a high-water content.
  • Drink water or fruit juice on a regular basis and avoid alcohol, or at least alternate alcoholic drinks with water.
  • Monitor body weight to track fluid intake (a kilogram change in weight roughly equals a litre of fluid gained or lost).

Here are some ideas for keeping your home cool:

  • use curtains, blinds or shutters on your windows
  • open windows in the morning and evening
  • turn your heating off and use air conditioning if you have it
  • check that your fridge and freezer are working properly
  • turn off any appliances that you don’t need

Medications that increase risk during hot weather

Some medications increase the risk of becoming ill during hot weather. The level of risk depend on your lifestyle and health status, as well your medications.

The medications list below is not exhaustive but serves as a prompt to consider action and assess the risks and benefits of any changes.

Medications which may increase the risk of poor health outcomes during hot weather include:

  • diuretics, especially loop diuretics, which can lead to dehydration and electrolyte abnormalities
  • medications that interfere with cardiovascular responses, such as antihypertensives and antianginal drugs
  • medications that interfere with sweating, such as anticholinergics or beta blockers
  • medications that cause diarrhoea or vomiting (which can lead to dehydration), such as colchicine, antibiotics, and opiates
  • medications that can decrease renal function, such as certain antimicrobials, immunosuppressants, non-steroidal anti-inflammatories, anti-ulcer agents, and chemotherapies
  • drugs with levels affected by dehydration, such as lithium, digoxin, and antiepileptics
  • drugs that alter states of alertness, such as hypnotics, anxiolytics, and analgesics
  • medications that can interfere with central nervous system thermoregulation, such as neuroleptics and serotonin receptor agonists
  • drugs that increase the basal metabolic rate, such as thyroxin

Storing medications during a heatwave

Most medicines should be kept below 25°C, so they should be stored somewhere cool, dry, out of direct sunlight, and away from windowsills.

Medicines should only be stored in the fridge if specified.

Learn more about why temperature management is important for medicines storage from the Specialist Pharmacy Service (SPS):

Resources

NHS UK

Find more information about the impact of hot weather on health and staying safe in the sun.