Thirst is a poor indicator of hydration levels in your body. Thirst kicks in after a 1-2% loss in body weight and by that time your performance is already affected. Stay ahead of this by ensuring you are properly hydrated throughout the day and especially before, during, and after your workout. Most food we consume in a day will give us 1L of fluids so strive to consume at least another 2L of fluids and even more in hot environments.