Extreme heat has a worse effect on older people than doctors thought. Researchers have said that the body's tolerance for heat goes down in older people. Rising global temperatures could increase the risk of illness or death for those aged 60 and over. This risk has been greatly underestimated. Heatwaves will put millions of older people at risk of heat stress. This is when the body loses its ability to cool itself. It can lead to death.

The researchers warned that we will have "intolerable heat" for longer periods of time. The over-60s are at risk from this because of three physical factors — they sweat less, their hearts have to work harder, and their blood vessels expand more slowly. These things limit the body's cooling functions. The Age UK found the study alarming. It said: "There's now no denying that extreme heat poses a very real health threat to our older population."