Small changes in internal temperature can apparently be used to drive the body’s circadian rhythms.
This suggests today’s invention: a new remedy for jetlag.
This takes the form of a pill-shaped pellet inside which is sealed a mobile phone receiver and a small motor whose output shaft rubs against the inside of the pellet wall.
When you are to take a flight to a new timezone, you swallow the device and engage an automatic sequence of calls to it. These are timed to occur so that the frictional heating of the pellet interior warms one’s body just enough, during its transit through the gut, to mimic the diurnal temperature variation normally experienced at your destination.