Wearing cozy socks when you go to sleep in order to keep the feet warm and induce your blood cells to widen and causing your muscles to relax – a process called vasodilation. You can take things a step further by keeping a warm water bottle at your feet.
The science: A study published in Nature found that vasodilation in the skin of the hands and feet was the best physiological predictor for the rapid onset of sleep. Keeping the hands and feet warm can rapidly induce vasodilation and thus promote a faster onset of sleep (Kräuchi, 1999).