Heatwave: how to stay safe?

What is a heatwave?  

A heatwave is a generic term for a period of time during which extremely high temperatures may cause health problems.

A heatwave must meet two parameters in order to be described as such: the duration of the episode (a minimum of 3 consecutive days) and the intensity of the heat.

In 2022, the UK has experienced two "red-warning" heatwaves so far, the first one was in July and the second one in August. The red warning given by the UK Met Office means that the weather conditions are extremely bad and can be risky for the general population, who is advised to take precautions in order to keep safe. There are two other types of warnings used by the Met Office:

• Amber: this warning means "be prepared". Weather conditions in the area concerned may disrupt people's plans, travel, provoke power cuts and property damage and can be potentially dangerous for people's lives.

• Yellow: this warning means "be aware". Weather conditions may be changing, and population is invited to plan ahead and be prepared for possible disruptions (travel, daily activities, etc).

Several record temperatures have been recorded in the UK this summer. Thus, on 19 July, a record temperature of 40.3 °C was recorder and verified by the Met Office in Coningsby, England. During the July heatwave the Met Office's red warning was issued for the first time in history and the UKHSA raised the Heatwave Alert to level 4 meaning "illness and death occurring among the fit and healthy – and not just in high-risk groups". In some parts of England national emergency was declared.

What are the health risks related to extremely high temperatures? 

Exposing a person to high temperatures for a prolonged period of time, without allowing the body to recover, can lead to serious health problems.

High temperatures can be dangerous for the body when it has not yet become accustomed to the heat, when the heat is humid and prevents the body from sweating, and when air pollution is present.

Our body will try to adapt to the temperature, activating thermal regulation mechanisms such as sweating, accelerated breathing and dilation of blood vessels to cool the blood down.

Symptoms associated with high heat include: 

• Dehydration, 

• Fatigue, 

• Muscle cramps, 

• Headaches, 

• Nausea, 

• Dizziness, 

• Muscle weakness, 

• Symptoms aggravation, if a chronic condition is present. 
  
  

Signs of dehydration include vomiting, diarrhoea, excessive sweating, dizziness, dry mouth and nose and reduced urine output in adults.

There is also a risk of hyponatremia, a decrease in the concentration of salt in the blood which can sometimes be the result of an excess of water intake over sodium or an excess of salt loss over water elimination. This is especially true for the elderly, as sweating is often impaired or absent starting from a certain age, but also for people with chronic conditions.

In the event of a heat wave, the most serious risk is a heatstroke, which may lead to death. This happens when the body's temperature regulation mechanism becomes insufficient and the temperature rises dangerously, provoking hyperthermia. 

If you or someone else has a heatstroke, you should immediately call 999, especially if the symptoms include:

• fast breathing or shortness of breath

• a fit (seizure)

• loss of consciousness

• not responsive

• very high temperature

• fast heartbeat

You can also call 111 or get help from 111 online, if you or someone else is suffering from heat exhaustion.

While waiting for the emergency services to arrive, here is what you can do to help the person with a heatstroke: 

Source : Firstaidforfree

What populations are most at risk in high temperatures? 

People who are most at risk are:

• People over 65 years old: the heat is much less noticeable, the feeling of thirst is impaired, and they sweat less,
  

• Children under 4 years old: they lose more water than adults, there is a risk of dehydration,
  

• Pregnant women: hydration is essential during pregnancy,
  

• People suffering with chronic conditions (Parkinson's disease, cardiovascular disease, asthma, obesity, mental disorders) and those with disabilities,
  

• People on medication such as aspirin, diuretics (Aldactone®, Amiloride®), neuroleptics (risperidone, olanzapine) and antimigraine drugs (Emgality®, Amjovy®).

Other groups of people may also be considered at risk, either because of their living conditions, if they live in highly urbanised areas and/or in poorly insulated housing, or because of their activities (this concerns outdoor workers and athletes).

People in difficult situations, homeless or isolated people, are also exposed to health risks related to high temperatures.

Staying safe in hot weather 

There are simple things you can do to prevent serious health problems, such as dehydration or heat stroke.

In the event of a heatwave, it is recommended to drink plenty of water and stay cool, avoid alcohol consumption, eat enough food, close your shutters and windows during the day, air the rooms at night and take warm (but not cold) showers. It is also important to keep in touch with your loved ones, especially those who are most at risk.

It is advisable to anticipate the first signs of heat suffering, even if they seem insignificant. You should therefore be prepared and well-informed before the period of high temperatures begins.

Before a heatwave 

• If you are a person at risk, make yourself known to your local healthcare services so that volunteers can provide assistance if needed
  

• If you know people at risk, register them with these services,
  

• Locate air-conditioned places to be when you need to cool down,
  

• Put together a first-aid kit to be prepared for the heatwave (water spray, fan, thermometer),
  

• Learn how to recognise the signs of heat stroke.

During a heatwave 

• Protect yourself from the sun

• Stay hydrated by drinking plenty of water, avoid sugary drinks and alcohol,
  

• Wear light, loose-fitting, bright clothing,
  

• Use fans and water sprays. Simultaneous use is most effective,
  

• Take regular warm showers,
  

• Spend several hours a day in a cool place,
  

• Rest during the hottest hours,
  

• Eat sufficiently and healthy (water-rich fruit and vegetables),
  

• Limit physical effort,
  

• Do not isolate yourself, talk to your family and neighbours,
  

• Protect your home from the heat,
  

• Act quickly in case of heat stroke symptoms

Source : Wolverhampton.gov.uk