How much water can the body absorb in a hour?

Drinking more than 500 ml per hour results in flushing. The excess will be flushed, which can be an issue if you consumed that water with nutrients (ie: vitamins, protein, etc...)

Too much water consumption can result in kidney stress as well. I train 5 days a week and drink an average of 2-3 liters of water a day at 500 ml intervals - with a minimum of an hour between servings.