A square of skin from a woman's shoulder is enlarged
and becomes a 3D cross section of layered skin.
Among hair follicles, blood vessels, and nerves is a cross section
of ducts with a coiled tube that rises to the surface.
A body has between two and four million sweat glands lying deep in the skin.
They are connected to the surface by coiled tubes called ducts.
You perspire constantly, even without exercise.
Fluid rises through the ducts and tube
to the surface and spreads across the skin.
Sweat is a liquid made from 99% water and 1% salt and fat.
Up to a quart of sweat evaporates each day.
The woman is at the gym lifting weights.
Drops of sweat are visible on her face, neck, and shoulder.
When your body becomes overheated, you sweat more.
The evaporation of sweat from your skin cools your body down.
The woman is lying on a mat.
Across her chest is a bar with 90-pounds of weight.
Sweat is visible on her forehead and face and she looks worried.
When you're frightened or nervous (imagine being pinned under heavy weights)
you also sweat more.
Your palms and forehead begin to sweat.
So do the soles of your feet and your armpits.
These are sites where sweat glands are most abundant.
A hand reaches down to lift the bar.