Click here for the government heatwave plan for England 
Click here for the HCPA Heat exhaustion symptoms and prevention poster
Click here to download the HCPA Heatwave considerations checklist
Click here for the HCC extreme weather health action card

Many people enjoy the hot weather but there can be serious health consequences from too much heat and vulnerable groups are particularly at-risk in prolonged hot spells. High temperatures have significant health consequences and are associated with increased mortality and increased morbidity.

Hot weather, especially when prolonged, with warm nights, can have effects on people’s health and on national infrastructure. To aid preparation and awareness before and during a prolonged hot spell, the heatwave plan has been created by Public Health England in association with other partners. It recommends a series of steps to reduce the risks to health from prolonged exposure to severe heat.

The harm to health associated with high temperatures is not inevitable.  There are things we can do all year round and in the emergency response context to minimise the impact on human health. Everybody has a role. The impact of high temperatures requires a cross-sectoral response.

Symptoms and causes of heat related illnesses

The main causes of illness and death during a heatwave are respiratory and cardiovascular diseases. Additionally, there are specific heat-related illnesses including:

Clients at risk:

EVERYBODY can be affected by high temperatures, but there are certain factors that increase an individual’s risk during a heatwave. These include:

  • Older age: especially those over 75 years old, or those living on their own and who are socially isolated, or those living in a care home
  • Chronic and severe illness: including heart or lung conditions, diabetes, renal insufficiency, Parkinson’s disease or severe mental illness
  • Inability to adapt behaviour to keep cool: babies and the very young, having a disability, being bed bound, consuming too much alcohol, having Alzheimer’s disease
  • Environmental factors and overexposure: living in a top floor flat, being homeless, activities or jobs that are in hot places or outdoors and include high levels of physical exertion


Older adults are more at risk of dehydration and even more so if there is extreme heat. As part of your preparation for extreme heat, staff education is important to prevent dehydration. There are many reasons of why older adults are at more risk, due to not drinking enough fluids, swallowing difficulties, kidney function, medications, and poorly controlled diabetes.

In extreme heat and dry conditions can cause dehydration and the body to overheat.

What to look out for:

  • Dryness Of the mouth, lips and tongue
  • Sunken eyes
  • Dry inelastic skin
  • Drowsiness
  • Dizziness, confusions or disorientation which can effect falls.
  • Low blood pressure.

In extreme heat it is vital that all staff are aware of the signs of dehydration. Dehydration is also associated with a more concentrated urine output and understanding the colour of urine can be useful to detect dehydration.


What actions do you need to take?

  • Insulation – thermal insulation to walls and roofs helps prevent solar gain. However, external wall insulation is problematic for solid wall construction.  Insulation of pipes, reduction of boiler flow temperatures, ventilation of service voids should all be considered.
  • Shading, reflection and protection – Various options to provide shading to limit heat gain. Internal shutters can provide some protection, as can curtains, but external protection (eg awnings) are preferable. Providing light-coloured finish to flat roofs and introducing green roofs can reduce solar gain.
  • Ventilation – Ideally, ventilation should be passive to avoid additional energy consumption needed for fans and air conditioning. However, window opening may not be appropriate in all circumstances (eg security concerns or homes in noisy locations).
  • Occupant behaviour – Taking steps to mitigate overheating is essential. This includes shading from the sun and understanding appropriate day and night ventilation.

Heat-Health Watch Service

As well as the Heat-Health Watch alerting system, other services exist.  The purpose of these various services are:

Heatwave warningTo provide early warning of high temperatures
Heatwave planning adviceTo provide advice throughout the summer period relating to high temperatures
National Severe Weather Warning ServiceTo provide warnings of severe or hazardous weather that has the potential to cause danger to life or widespread disruption. These warnings are issued to the public to prompt consideration of actions that they may need to take and the emergency responders to trigger their plans to protect the public
General weather forecastsTo enable the public to make informed decisions about their day to day activities

Guidance and Resources