It’s best to get your body hydrated before you even think about heading to the gym. One way to determine your overall hydration status is to check out the color of your urine first thing in the morning. According to the Academy of Nutrition and Dietetics, lemonade-colored urine is a sign of appropriate hydration, while dark colored urine (think apple juice), indicates a deficit in H20.
While there is no one-size-fits-all method to determining fluid needs during exercise, a good place to start is drinking about 2 cups of water 2 to 3 hours before exercise and 1 cup of water 10 to 20 minutes before working out. The goal here is to minimize dehydration—which can cause low energy, and muscle cramps or spasms—without drinking too much water. You should try to also stay hydrated throughout your workout. Consider drinking 1 cup of water for every 15-30 minutes of intense physical activity, especially if you are sweating profusely or are training in a heated environment. Again, this may take a bit of experimentation until you find what works best for your body.