Why is alcohol dangerous in a heatwave, and should I cut it out completely?

Parisians have drinks along the Canal Saint-Martin on Thursday, before the city introduced a temporary ban on consuming takeaway alcohol in public. Photograph: Ludovic Marin/AFP/Getty Images View image in fullscreen Parisians have drinks along the Canal Saint-Martin on Thursday, before the city introduced a temporary ban on consuming takeaway alcohol in public. Photograph: Ludovic Marin/AFP/Getty Images Explainer Why is alcohol dangerous in a heatwave, and should I cut it out completely? Those partial to a pint may be relieved to know a modest of amount of weak beer may actually be beneficial European heatwave live – latest updates As Europe endures a record-breaking heatwave, countries are taking steps to keep people safe and prevent health services from becoming overstretched. Parisians face a temporary ban on drinking alcohol in public to reduce the pressure on the hospitals after a four-fold rise in cardiac arrests in a 24-hour period. We look at why drinking alcohol can be dangerous in a heatwave. What does alcohol do to the body? A cold beer in the sun need not be a problem, but strong drinks and large volumes can be dangerous. Alcohol is a diuretic, and estimates suggest every 1ml of alcohol stimulates the body to produce about 10ml of urine. If you have a 25ml nip of 40% whisky, that amounts to 10ml of alcohol and 15ml of water. The 10ml of alcohol will cause you to produce 100ml of urine, leading to a net water loss of 85ml. There’s a smaller effect with beer. A pint, or 568ml of 5% beer contains about 28ml of alcohol, which stimulates about 280mls of urine, but the body gains about 260ml of water. “You’re better off with that pint of beer, you are more hydrated than you would be if you didn’t drink it,” said Prof Ron Maughan, an honorary professor at the University of St Andrews who has worked with the British Olympic Association. But drinking pint after pint can be a problem because the sheer volume stimulates urination. “When you drink not one pint of beer but many pints of beer, you run into difficulties,” he said. Why is there a risk of heart attack? Heat and alcohol can put immense strain on the heart. People sweat more in hot weather and the loss of water causes a drop in blood volume. At the same time, blood vessels near the skin widen to help the blood lose more heat as it is pumped around the body. Alcohol magnifies this effect, causing the blood vessels to widen even further. Together, this drives a drop in blood pressure, so the heart has to work to harder to ensure enough oxygen reaches the brain and other organs. If the heart cannot match the demand, people can feel dizzy and collapse because too little oxygen reaches the brain. Losing sodium, potassium and magnesium through dehydration can make matters worse. The loss of electrolytes can cause arrhythmias or irregular heart beats. In the most severe cases, the heart itself receives too little blood to work properly, which can lead to a heart attack. “If there is too little