I used to have practices where I’d routinely drink 168 oz (a full 40 oz bottle plus a gallon of refills) over the course of a couple hours. 37 cups is a gallon more than that. It’s enough water to cool off about another 2000 kCal of exercise.
I wonder if he’s still throwing down 4-6 megacalorie days now that he’s retired.
You also lose salts sweating, so if you drink water, sweat, and don’t replace salts in your blood the inside now saltier parts of your body (like your brain) can pull water out of your blood and swell up, and your brain is trapped in your skull and has nowhere to expand to. Even if you lose lots of water sweating you can still get edema from too much water. You also lose water to respiration which doesn’t take salts with it.
I’ve never been super careful about it exercising. I just drink only when I’m thirsty, and hate the taste of gatorade, so if gatorade tastes good I drink that until it doesn’t, and if it doesn’t taste good and I’m thirsty I drink water. Or if my pee isn’t clear I drink water.