From why people blush to why men go bald

We explore some of the curious questions that science can answer

Testosterone causes baldness in the hair follicles that are sensitive to one of the hormone’s breakdown products, DHT (Getty)

Why do people blush?

Uncontrollable, severe facial blushing is a physical condition caused by overactivity in the sympathetic nervous system, a system made up of nerves over which we have no control. These uncontrollable nerves may become especially active due to social and emotional stimuli and may be very embarrassing; people may blush while meeting friends in the street or paying in a shop. Suddenly the face turns deep red, turning an ordinary social situation into an embarrassment, making social and even professional life almost impossible. We also blush as a result of our emotions. Strong emotion causes an increase in blood supply to the face, which is why we look red. The colour disappears after a minute or so, as the sympathetic nervous system, and hence the peripheral circulation, returns to normal.

Of the energy consumed by a human, what percentage is lost as heat?