Due to hot weather late over the weekend, East Midlands Ambulance Service (EMAS) experienced higher demand for the emergency service.
On Saturday, EMAS were called out to 630 Category A (life-threatening) incidents, and a further 771 on the Sunday.
Combined, a 33% rise in calls in comparison to June 25-26 2010 — although the weather was generally cooler (average temperature 16C) last year.
According the EMAS, most of the increase was due to chest (23% of calls) and breathing problems (17%), triggered by sudden high temperatures.
Director of Operations Diane Lee said: “As we enter the summer months we are not expecting demand to ease – our service is always busy and people always need our help.
“Our staff and volunteers have made a fantastic effort in the face of huge increases in demand and it is to their credit that we are continuing to offer effective emergency services to the people of the East Midlands.
“Whilst we don’t want to dissuade anyone from calling for help if they need it, we would like to remind everyone to only dial 999 in a genuine emergency.
“Our priority is to help patients with life-threatening illnesses or injuries as quickly as possible.
“That’s why we ask anyone with less urgent conditions to consider calling NHS Direct for advice on 0845 46 47.”