make mine a cold drink.......

Here is a piece of research that you could put into practice fairly easily:

Cold Drink Ingestion Improves Exercise Endurance Capacity in the Heat.

Conclusion: Compared with a drink at 37[degrees]C, the ingestion of a cold drink before and during exercise in the heat reduced physiological strain (reduced heat accumulation) during exercise, leading to an improved endurance capacity (23 +/- 6%).