It's also made with a light weight bottle to use less plastic.

The nice thing about weight training is that anything with weight will work--a dumbbell, a full water bottle or a sock full of sand...your body doesn't know the difference.

When my husband came home a few hours later he found me not quite asleep in his winter-weight winceyette pyjamas, clutching a hot-water bottle and shivering under two duvets and a blanket.