Or, more specifically, heat acclimation reduces the build up of lactate in muscles. Assuming regular use of the sauna, then one might presume that this would result in some level of heat acclimation. Additionally, heat acclimation lowers the aerobic metabolic rate during exercise as well. Perhaps this also plays a role in the enhanced running endurance from heat acclimation mentioned previously.
Muscle and plasma lactate accumulation with exercise was greater (P less than 0.01) in the hot relative to the cool environment both before and after acclimation. Acclimation lowered (P less than 0.01) aerobic metabolic rate as well as muscle and plasma lactate accumulation in both environments. The amount of muscle glycogen utilized during exercise in the hot environment did not differ from that in the cool either before or after acclimation. These findings indicate that accumulation of muscle lactate is increased and aerobic metabolic rate is decreased during exercise in the heat before and after heat acclimation; increased muscle glycogen utilization does not account for the increased muscle lactate accumulation during exercise under extreme heat stress; and heat acclimation lowers the aerobic metabolic rate and muscle and blood lactate accumulation during exercise in a cool as well as a hot environment. (via.)