The trial will include groups of people aged 18 to 30 and over the age of 65 who will be given a slushy drink made of only water to drink. They will be asked to walk on a treadmill in a 40C ...

With just two ingredients — and, well, water and ice too, but that's not hard to come by — you can make a delicious, refreshing slushy. It's darn near an ice cream or a liquid sorbet.