During a workout, you break down muscle tissue. After a workout, your body goes through a process to repair any "damage" that has been made. If you provide your body with proper hydration, it will return the favor with optimal bodily functions.
1. Supports Nutrient Transport and Muscle Growth
Your body requires water to transport nutrients to different cells of your body. Without the proper hydration, the process of protein synthesis is diminished or delayed.
2. Boosts Cognitive Function
Water has no caloric content, but it's the medium for many chemical reactions that occur within the body. It also plays a role in all of our bodily functions. Our bodies are made up of over 70% water. So it only makes sense to provide it with proper hydration. Optimal levels of hydration can improve cognitive function and increase productivity. Dehydration as little as 1-2% can decrease mental performance.
3. Flushes Out Toxins
When you're dehydrated, your body conserves fluid. This process increases the amount of chemical and waste products in your urine. If the concentration of waste products in your urine is high, the color of your urine becomes darker. If your body is hydrated, it's able to flush out toxins more frequently.
A good rule of thumb for proper hydration is drinking so that your urine color stays between clear to light yellow. If your urine is dark yellow, you should drink more. If your urine color is brown, please consult a doctor.
References:
Popkin, Barry M et al. “Water, hydration, and health.” Nutrition reviews vol. 68,8 (2010): 439-58. doi:10.1111/j.1753-4887.2010.00304.x
Riebl, Shaun K, and Brenda M Davy. “The Hydration Equation: Update on Water Balance and Cognitive Performance.” ACSM's health & fitness journalvol. 17,6 (2013): 21-28. doi:10.1249/FIT.0b013e3182a9570f