The UK must be better prepared for the health impact of heatwaves, as the effects of climate change mean more will occur, experts have said.
Researchers at the London School of Hygiene and Tropical Medicine say plans will have to be constantly updated.
July this year was the hottest UK month since records began in 1960, with one day hitting a high of 36.5C.
The British Medical Journal paper said people who would be vulnerable in heatwaves should be targeted directly.
When temperatures remain abnormally high over more than a couple of days, the excessive heat can prove fatal.
In 2003, a heatwave spanning 20 days in France caused more than 14,000 excess deaths.
During that heatwave, more than 2,000 people died in England - 85% of these deaths were amongst people aged 75 and over.
The health impact of this year's heatwave is not yet known.
By the 2080s, it is predicted that heatwaves will happen in England every year.
As well as the elderly, the socially isolated and those with heart conditions, people with diabetes or mental illnesses are at a greater risk of death during a heatwave.
HOW TO COPE WITH A HEATWAVE
Plan your day so you stay out of the heat
Avoid going out from 11am-3pm - the hottest part of the day
If you do go out, stay in shade, wear hat and light, loose clothes
Take cool showers or baths - splash yourself with cold water, particularly your face and back of your neck
Eat more cold food - salads and fruit
The Department of Health has a heatwave plan for England which spells out what needs to be done by health, social care and other bodies to raise awareness of hot weather risks and how people can protect themselves.
One thing people can do is to look out for signs of heat exhaustion - one of the first signs that someone is at risk.
Symptoms include headaches, dizziness, nausea and vomiting, muscle weakness or cramps, pale skin, weak pulse and high temperature.
Heatstroke, which can result in organ failure, brain damage or even death, can develop if the symptoms of heat exhaustion are left untreated.
Paul Wilkinson, head of the unit at the London School of Hygiene and Tropical Medicine which carried out the research, said: "We are going to have to do more with a problem that is going to become increasingly frequent and more of a burden to us.
"As heatwaves get more and more powerful, more and more people will potential be vulnerable. Even fit people can succumb.
"We have to be very clear that our responses are adequate."
He said the UK could learn a great deal from Mediterranean countries.
He said one move could be to fit buildings with air-conditioning.
A Department of Health spokesman said that careful planning meant the NHS and social care services were well placed to respond to a heatwave.
"Our plans for a heatwave are constantly evolving to reflect changes in the UK's climate and we update and improve our heat wave plan every year. By taking action in advance we can help to reduce the impact and protect people from the effects of high temperatures."