This year is on track to be the hottest in recorded history. With rising temperatures and more intense and frequent heatwaves, keeping cool in summer will get harder. Air conditioning can only go so far, especially when extreme heat raises the risk of electricity outages. Wearing light, loose-fitting clothing is well recognised health advice to beat the heat in sweltering temperatures, especially important given that heatwaves kill more people than any other extreme weather event. But increasingly, researchers and fashion brands are turning to clothes that claim to make people physically cooler. New fabrics that take the heat off the