Much of England is forecast to experience very warm weather from Saturday night through to Tuesday morning.
Dr Owen Landeg, Scientific and Technical Lead at PHE said: "Much of the advice on beating the heat is common sense and for many people spells of warmer weather are something they very much enjoy.
"However, for some people, such as older people, those with underlying health conditions and young children, the summer heat can bring real health risks. That’s why we’re urging everyone to keep an eye on those you know who may be at risk.
"If you’re able, ask if your friends, family or neighbours need any support. Also take water with you when travelling and keep up to date with weather forecasts.
"It’s also worth remembering the practical steps to keep homes cool during the day as this can aid sleeping at night and give the body time to recover from the heat."
Temperatures are set to rise to 27 degrees on Saturday and remain high over the weekend.
Will Lang, Head of Civil Contingencies at the Met Office, said: "Across most parts of the UK we’re expecting to see temperatures building, reaching heatwave thresholds across the majority of England over the weekend. High temperatures will remain a feature of the forecast until Tuesday, when fresher conditions arrive curtailing heatwave levels."
The top ways for staying safe when the heat arrives are to:
* Look out for those who may struggle to keep themselves cool and hydrated; older people, those with underlying conditions and those who live alone are particularly at risk
* Stay cool indoors – many of us may need to stay safe at home this summer, so know how to keep your home cool
* Close curtains on rooms that face the sun to keep indoor spaces cooler and remember it may be cooler outdoors than indoors
* Use cool spaces considerately if going outdoors, and wash your hands regularly
* drink plenty of fluids and avoid excess alcohol
* Never leave anyone in a closed, parked vehicle, especially infants, young children or animals
* Try to keep out of the sun between 11am to 3pm, when the UV rays are strongest
* Walk in the shade, apply sunscreen and wear a wide-brimmed hat, if you have to go out in the heat
* Avoid physical exertion in the hottest parts of the day
* Make sure you take water with you if you are travelling
* During warm weather going for a swim can provide much welcomed relief; take care and follow local safety advice if you are going into open water to cool down
* Remember that while coronavirus (COVID-19) restrictions are in place, you will need to follow any additional government guidance to use public spaces safely