Hospitals are bracing for a spike in demand on emergency services as temperatures plummet this weekend.

The UK Health Security Agency (UKHSA) has issued an amber Cold-Health Alert for the whole of England, lasting until midday next Wednesday.

Icy conditions make falls more likely and cold temperatures can raise risk of strokes, heart attacks and respiratory illnesses such as pneumonia.

Dr Agostinho Sousa, the agency’s head of extreme events and health protection, said: “The forecasted temperatures can have a serious impact on the health of some people, including those aged 65 and over and those with pre-existing health conditions, and it is therefore vital to check in on friends, family and neighbours that are most vulnerable.”

Sub-zero temperatures are forecast across the UK, with warnings for ice also in force after much of the UK was lashed by strong winds and heavy rain.

Under the system used by the UKHSA and Met Office, an amber alert means cold weather impacts are likely to be felt across the whole health service for an extended period of time, with potential for the whole population to be at risk.

Professor Arlene Wellman, group chief nurse for St George’s, Epsom and St Helier A&E departments in London, said hospitals were very stretched and under extreme pressure.

She also urged people to check on vulnerable friends and relatives, adding: “We expect to see higher demand during cold spells and in the days that follow, and are doing everything we can to handle this.

“You can help us by checking in on vulnerable people and using services best suited to your needs, such as NHS 111.”

Prof Wellman also advised people to stock up on medications or prescriptions and stay for two days home if sick with symptoms of norovirus.

Dr Richard Jennings, the hospitals’ group chief medical officer, also urged people to seek help from the appropriate service, making use of NHS 111 where possible.

He said: “It’s a common misconception that you will be seen more quickly if you visit an emergency department when it’s not an emergency – but in fact, you will wait longer.”

The cold snap comes after NHS leaders warned that a “quad-demic” of flu, Covid, respiratory syncytial virus and norovirus was putting pressure on hospital capacity.

Cases are expected in increase in the wake of festive gatherings where infections can spread.

NHS national medical director, Professor Sir Stephen Powis, said on New Year’s Eve: “The winter flu season has not only hit the NHS early this year, but it is potentially on track to be one of the worst we have ever seen, as the ‘quad-demic’ continues to increase pressure across services.

“Frontline NHS staff are currently under significant pressure – and as families and friends have gathered over the festive period and to celebrate the new year, we expect the peak of seasonal viruses is yet to come.”

Age UK’s director Caroline Abrahams said the cold weather would bring the government’s decision to limit winter fuel payments “into sharp relief”.

The charity has already been contacted by people “worrying about what to do”, she added.

Ms Abrahams said: “We urge older people to do everything they can to stay warm, even if that means risking spending more on their heating than they feel they can afford.

“The energy companies are under an obligation to help if you are struggling and there may be support available from your local council too. Better that than to jeopardise your health.”