Physiology

The amount of water and electrolytes needed for proper hydration vary from person to person

When scientists exposed people to the virus that causes COVID, only a subset got sick. Studying them could offer clues to immunity

People whose eyes dilated more performed better on tests of working memory

The skeletons of scribes from ancient Egypt show deterioration from sitting and kneeling

A Doctor Who superfan explains how the unusual cardiovascular system of the alien Time Lords could evolve and function

Uncontrollable sobbing is uniquely human, and it may be our emotions running out of our faces, a way to connect us with other people

Experts explain how moving in reverse can take pressure off your knees and improve flexibility

When the moon fully eclipses the sun, it’s not just the sky that changes. Your eyes do, too

The humble vacuole, a garbage dump inside cells, turns out to play an important role in the aging process

The answer isn’t just about temperature. Our physiology, psychology and clothing choices also factor in

The world has launched into an era of injectables not just to treat obesity but to manage weight. Is that all good news?

The research focused on figuring out what enables certain sperm to gain some competitive advantage over millions of others fighting for the same prize.