Here's how to best hydrate before a tennis match in extreme heat:

Start early: Don't wait until the day of the match to hydrate. In the days leading up to your match, consistently drink plenty of water throughout the day, even if you don't feel thirsty.

Pre-match hydration: On match day, begin by drinking 12-16 ounces of water as soon as you wake up.

Electrolytes: Follow that up with another 12-16 ounces of water, a sports drink, or diluted juice 60-90 minutes before you hit the court. Electrolytes, especially sodium, help your body retain fluids.

Top it off: Ten minutes before your match, consume another 8 ounces of water or a sports drink.

Here are some additional tips:

Listen to your body: While thirst is an indicator of dehydration, aim to drink consistently throughout the day, not just when you feel thirsty.

Beat the heat: Stay cool in an air-conditioned space before the match. Consider using an ice vest, ice blanket, or cold towels for 15 minutes about an hour before you play.

Slush it up: For a combined cooling and hydration effect, try consuming 8-20 ounces of a slushy drink about 30 minutes before the match (gradually, not all at once).

Avoid dehydrating drinks: Limit or avoid sugary drinks, soda, coffee, and alcohol, as they can actually accelerate fluid loss.

By following these tips, you'll be well on your way to staying hydrated and performing your best in the extreme heat.