An unprecedented summer surge in demand on A&E departments saw almost 2.2m people turn up for treatment at hospitals in England last month - a record figure.
NHS trusts reported an increase in the number of patients needing treatment for breathing problems and a urise in cases of cuts, sprains and fractures which placed additional pressure on services.
The hot weather led to an increase in the number of elderly people needing treatment for dehydration as emergency departments helped 100,000 more people in July compared with the same period last year - a five per cent increase.
The number of emergency hospital admissions rose by 6.3 per cent.
Latest figures also show that the number of patients waiting more than a year for non-urgent surgery in England rose to its highest level in more than six years.
The figure reached 3,517 in June, an increase of more than 400 from May, and the highest since April 2012.
While improvements were made on waiting times in A&E compared to the winter, many hospitals still struggled to meet the requirement for patients to be seen within four hours.
At Hull and East Yorkshire Hospitals NHS Trust, 79.6 per cent were either admitted, transferred or discharged in four hours in July. Dr Kirsten Richards, Consultant Physician in Elderly Medicine, said: “We’ve seen more people being admitted on to our wards with symptoms linked to the heat, including dehydration, falls and breathing difficulties.”
At Leeds Teaching Hospitals 83.9 per cent of A&E patients were seen in four hours last month.
Deputy Chief Executive Suzanne Hinchliffe said: “We have seen an increase in the number of people attending A&E compared to last year.
“There was a particularly noticeable increase of very sick patients attending in July, which means they need to stay longer in hospital and this has an impact on how quickly we can see people in A&E.”
At York Teaching Hospital NHS Foundation Trust, there were 18,903 A&E attendances in July - an increase of 8.4 per cent on the same month last year.
A trust spokeswoman said: “However despite these pressures our A&E performance for patients seen within four hours tracked the national position and was an improvement on the same period last year.”
Donna Kinnair, Director of Nursing Policy and Practice at the Royal College of Nursing (RCN), said: “This summer’s heatwave has hit healthcare services hard. Nurses are seeing more cases of heart failure, renal failure and dehydration - all conditions linked to hotter weather.
An NHS England spokesman said: “As temperatures soared, the NHS saw an unprecedented summer surge last month with a record 2.2m patients attending A&E, and, thanks to the hard work of staff, nine in 10 people were seen, treated and admitted or discharged within four hours.”