An asphalt or acrylic court in direct sun runs dramatically hotter than the ambient air — surface temperatures 20 to 40 degrees above air temperature are routine, and you're standing in that radiant heat for hours.
The three things that actually move the needle
1. Pre-cooling beats mid-game cooling
Starting a session already warm means you spend the whole time chasing your own core temperature. Cooling down before you play — sitting in shade, a cold drink, a cold towel on the neck for a few minutes — buys you meaningfully more playing time than the same intervention at the 90-minute mark.
2. Evaporative cooling on the right places
A wet cooling towel works by evaporation, so it needs airflow to do anything. It's most effective on the neck, wrists, and inner forearms, where blood vessels run close to the surface. Draping one over your shoulders under a shirt does almost nothing.
Rewet it every 20 minutes or so. Once it's body temperature it's just a damp cloth.
3. Sun protection you'll actually keep on
Sunscreen on forearms fails predictably: you sweat, you wipe, it's gone, and reapplying mid-session is unpleasant with a grip in your hand. UV arm sleeves solve the compliance problem rather than the physics problem — a UPF 50+ sleeve doesn't need reapplication and, counterintuitively, most players report feeling cooler wearing one because it blocks radiant load.
Face, ears, and the back of the neck still need sunscreen. A hat with an actual brim handles most of it.
Hydration, briefly and without the myths
Water alone is adequate for sessions under about an hour. Past that, in real heat, you're losing enough sodium that plain water can start working against you. Add electrolytes for long sessions — and note that you're drinking to replace sweat losses, not to hit an arbitrary daily number.
Practical marker: pale yellow urine. Completely clear means you're overdoing it, which carries its own risks.
Know the actual warning signs
Stop playing and get to shade immediately if anyone experiences: stopping sweating despite the heat, confusion or disorientation, dizziness, nausea, or a headache that comes on fast. Heat exhaustion progressing to heat stroke is a genuine medical emergency, and on a court it typically gets waved off as someone being tired.
The competitive instinct to play one more game is the thing that gets people hurt.