Dehydration and performance: less clear than you think

It is often claimed that losing 2% of body mass sharply degrades performance. A meta-analysis of real time trials found a non-significant 0.06 ± 2.72% change with exercise-induced dehydration, while drinking to thirst beat taking no fluid by 5.2%. The ACSM position stand still recommends keeping mass loss under 2%. Both positions are worth knowing.