0 graphs% -- normal heat regulation and performance

1% -- thirst is stimulated, heat regulation during exercise is altered, performance begins to decline
2% -- further decrease in heat regulation, increased thirst, worsening performance
3% -- more of the same
4% -- exercise performance cut by 20 - 30%
5% -- headache, irritability, "spaced-out" feeling, fatigue
6% -- weakness, severe loss of thermoregulation
7% -- collapse is likely unless exercise is stopped