A packed studio has no wind to hide your sweat.
Indoor cycling looks like cycling, but for hydration it behaves like a hot class. There's no airflow to evaporate your sweat, so you soak through a 45-minute ride and actually feel it — endurance-level fluid and sodium loss in a studio. Here's what to put back, dosed to you rather than to a one-size tab.
Get your class number →Why spin soaks you like hot yoga.
Out on the road, 20 km/h of wind flashes the sweat off your skin and keeps you deceptively dry. In a studio, the air is warm and still, a room full of bodies, one fan aimed at the front — so your body has to sweat harder to dump the same heat, and it drips instead of evaporating. The result is a high sweat rate you can see puddling under the bike. Sweat sodium varies about tenfold between riders, so the salty sweater in the back row is losing far more than the sports drink he's sipping puts back.
The plan around a class.
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Hot yoga & sculpt
The same hot-room, no-wind sweat — and the heat-adaptation angle, honestly caveated.
Road cycling
Where the wind lies the other way — you sweat hard but never feel it.
Your sweat rate
Weigh in before and after a class — the puddle is real, the scale proves it.