No scientific basis to needing to drink water continually. What is important is keeping the body's core temperature at a safe level to avoid heatstroke. There is a problem with lack of sodium for people on a low salt diet. It is recognized now that when people go on a low salt diet based on their doctor's recommendation that they end up on a no salt diet and are seriously sodium deficient.
I take magnesium and potasium supplements and add a measured amount of table salt to the food I cook. No need for Gatorade with its harmful ingredients like BPAs from the bottle and no need to add to the landfills as none of the plastic water bottles actually get recycled.