the first day of "the Seven Pillars of Health" (and several after) are about water and getting enough of good water.

• your body is about 70% water
• your muscles are about 80% water
• your brain is about 85% water.

If you don't get enough water, your body suffers.  And...you lose about 2 quarts of water every day just by living.

Short story...get enough water.  Take your weight, divide by two and drink that many ounces.  yes.  that many.