How Hydration Affects Performance:It's more difficult to give 100% in the gym when you're dried out. Your body has less water, which implies less blood volume, so your heart needs work harder to pump all the high-viscosity blood, increasing your heart rate. Your center temperature is likewise hotter, so your digestion is somewhat less proficient. In general, you need to work harder to accomplish a similar end result
Increasing your water intake is not the only factor effecting your hydration, you need to replace the electrolytes (specifically sodium) you lose with sweat. Electrolytes enable your body to more efficiently utilize both glucose (fuel) and water. These electrolytes are vital to your neuromuscular function. Keeping your muscles happy and fueled will allow you to get the most out of your workout, whether it's hitting the gym, or going on a run.
Replacing What You Lose
It's very important to replace the electrolytes lost in order to prevent muscle weakness, cramps, and spasms. All of which will result in a mediocre gym session, or injury. The two electrolytes you the most through sweat are Sodium and Chloride, while slowly losing Potassium, Magnesium, and Calcium.
The vast majority of people lose between 0.5 to 1.5 liters of perspiration for each hour, however, It's exceptionally reliant upon outside factors like exercise, intensity, and the atmosphere. A lot of sweat is both good and bad, the good is it's your body's natural way of cooling off to prevent overheating, and bad when you're not replacing what you're losing. This is how you quickly become dehydrated, resulting in a performance loss.
But on the other hand, there's a hereditary part to it. A few people simply sweat more than others, and some lose more sodium per drop.
What Are Your Options?
Before your workout, you can take a good Pre-Workout and BCAA supplement that has Sodium, Potassium, and Magnesium on the ingredient panel. It's always a good idea to prepare your body with the electrolytes you know you're going to lose. RevLabs has 2 great products for this, 3-in-1 and Enamour
Post workout it's best to take an all natural Whey-Protein Supplement, these are typically packed full of all the essential nutrients your muscles need to recover, as well as electrolytes to assist in re-hydration.
Weighing yourself before and after a workout is also a good indication of how much water you've lost. Remember water weight you've lost is not weight loss, it's dehydration. A 2% body weight reduction implies you're dried out. That is, your thirst repairman isn't adequate enough to keep you hydrated.
Additionally if you're actively training, here is an easy way of calculating how much water you should be consuming daily.
Daily Water Intake in Ounces = Your Body Weight ÷ 2