Kidney Care UK is issuing advice in response to rare Red and Amber alerts issued by the UK Health Security Agency (UKHSA) and the Met Office this week because hot weather increases the risk of acute kidney injury (also known as AKI).
AKI is linked to around 100,000 deaths every year in hospital in the UK (equivalent to 10 every hour) and affects 1 in 5 people admitted to hospital as an emergency. It usually happens as a result of another illness or infection, such as sepsis, but it can also be caused by dehydration, low blood pressure, a reaction to medication or kidney stones.
Importantly, research highlights that acute kidney injury is more likely in hot weather. The risk increases as the temperatures rise, particularly above 25C; the risk of AKI is 62% more likely at 32C than at 17C.
During a seven day heatwave in July 2021, AKI diagnoses increased by 29%. Recent data released from the Department of Health and Social Care highlighted that there were record attendances in A&E departments in May 2026bdue to the heatwave, with 2,457,398 attendances (25,000 more than the previous record, set in March 2026).
Signs and symptoms of AKI
Signs that you may have acute kidney injury can appear suddenly or over a few days and include:
- feeling generally ill, like having a hangover
- being very thirsty
- feeling or being sick
- producing less urine
- swelling of the legs or feet
- excessive tiredness
- confusion
Those most at risk of developing AKI are people with diabetes, high blood pressure, chronic kidney disease (CKD), heart failure and those over 65 years of age, although it can happen to anyone, especially if they are dehydrated.
With lots of outdoor activities taking place at the end of June, including festivals and World Cup screenings, Kidney Care UK wants to ensure that people understand what to look out for and what to do to protect their kidney health.
Reducing your risk of getting unwell
Fiona Loud, Policy Director at Kidney Care UK, said:
Those most at risk of developing AKI should ensure that they drink plenty of water if high temperatures are forecast and avoid caffeinated drinks (including tea and coffee, and iced versions of these too). If you find yourself experiencing symptoms of AKI, particularly if you are in an at-risk group, please seek advice from a healthcare professional.
It’s also important to follow NHS advice on how to be sun safe, and reduce your risk of getting unwell in high temperatures as this can put unnecessary strain on your kidneys. Everyone knows the importance of wearing sunscreen during a heatwave, we’d like to see people recognising that their kidneys need protection in this weather too. As well as remembering ‘slip, slop, slap, slide, shade’ we’d like to add in a vital hydration reminder to ‘sip’ too.
Treatment for AKI
Treatment for AKI will depend on the cause and severity; for some, treatment may only be to drink more water. Some may need to be given a drip, antibiotics or an adjustment to medication for a short period of time. Most treatment will be carried out by a GP but in severe cases people may need to be hospitalised and undertake a short course of dialysis.
Most people with AKI will only need dialysis for a few days/weeks and will make a full recovery with no longer term treatment needed. However, repeated instances of AKI increase the risk of developing chronic kidney disease and each recurrence roughly doubles the likelihood of progression to CKD.