India, June 24 -- With north India's plains sweltering under a relentless June heatwave and temperatures consistently breaching 40degC, the line between summer discomfort and a medical emergency has thinned. The gap between morning and evening cooling is shrinking, leaving people vulnerable to severe heat illnesses. Also read | HT Health Talk: You asked, our experts answered how to manage migraine in summer

Many people use 'heat exhaustion' and 'heatstroke' interchangeably, but medically, they are entirely different beasts. Understanding the threshold where one crosses into the other can save a life. Moreover, if you suspect someone near you has suffered heatstroke, your immediate actions before emergency medical services arrive are vita...