Asthma and Lung UK said more than three million people are at risk of attacks or flare-ups. Clinical lead Dr Andy Whittamore said: “When pollen levels are at their highest this can be deadly for those with lung conditions like asthma who can suffer serious symptoms and have life-threatening attacks. “These attacks can leave people fighting for breath, which can be terrifying, but there are things they can do to look after themselves.”
The charity urges sufferers to use their preventer inhaler and keep a reliever device with them at all times.
It also advises staying indoors when pollen is high and to keep an eye on weather forecasts.
The warning comes as a sizzling North African blast sweeps into the UK this weekend – with forecasters predicting the hottest May day in 100 years.
The current record is 27.8C (82.04F) in Camden, north London, in May 1925.
Jim Dale of British Weather Services said: “It’s a three-day mini-heatwave. High pressure will stay through Saturday and most of Sunday, maybe even in the east on Monday.”
Those enjoying hints of the hot spell included Jennifer Shulver and son Edward, two, who visited the stunning wisteria display at Exbury Gardens and Steam Railway in the New Forest, Hants, yesterday.
And there was a full rainbow at Filey Brigg in East Riding, Yorkshire, as rain finally cleared away. Mr Dale said the “arch of warmth” will spread across most of England and Wales but coasts will be cooler.
However, temperatures of up to 25C (77F) will also mean high pollen levels.
This risks triggering breathlessness and wheezing in more than half of people with asthma (59 percent) and more than a quarter of those living with chronic obstructive pulmonary disease (COPD), says Asthma and Lung UK. Dr Whittamore said: “Using preventer inhalers as prescribed is important. The medicine reduces sensitivity and swelling in airways, helping to prevent symptoms before they start.
“We also advise to carry reliever inhalers, especially when enjoying the sunshine. The third thing is to use a steroid nasal spray every day, together with non-drowsy antihistamine tablets to help stop the allergic reaction.”