Health officials have warned of increased health risks as hot weather is expected to affect large parts of England this week.
The UK Health Security Agency (UKHSA) has issued heat-health alerts for all eight regions of England from 09:00 BST on Monday 3 August until 09:00 on Wednesday 5 August.
Amber alerts, indicating a higher risk to health, are in place for the East Midlands, East of England, South East and London.
The North West, Yorkshire and the Humber, West Midlands and South West have been placed under yellow alerts.
The UKHSA said the amber warning could lead to increased demand for healthcare services, particularly among vulnerable people.
Those aged over 65 and people with existing health conditions, including cardiovascular and respiratory diseases, are considered particularly at risk.
Polly Ashmore, acting consultant in public health at the UKHSA, urged people to take precautions during the hot weather.
"Periods of hot weather can result in serious health outcomes, especially for older adults," she said.
She also urged people to check on elderly relatives and neighbours, as well as people with underlying health conditions who may need additional support.
People are advised to drink plenty of fluids, avoid direct sunlight during the hottest part of the day and take steps to keep their homes cool.
The UKHSA recommends closing curtains and windows in rooms facing the sun, avoiding strenuous activity during the hottest hours and planning exercise or outdoor activities for cooler parts of the day.
People should also avoid excessive alcohol consumption and take water with them when travelling.
The agency warned that children, older people, people living alone and those with underlying health conditions may be less able to cope with high temperatures.
It also reminded people never to leave children, vulnerable adults or animals inside a parked vehicle, even for a short period.
Those going outside are advised to seek shade, wear suitable clothing and a wide-brimmed hat, use sunscreen and avoid the strongest sunlight, particularly between 11:00 and 15:00.
People planning to cool off in rivers, lakes or other bodies of water have also been urged to follow local safety advice.
The UKHSA said people taking medication should check storage instructions, while fridges, freezers and fans should be checked to ensure they are working properly.
Further advice on heat exhaustion and heatstroke, including what to do if symptoms develop, is available through the NHS.
