Nearly 80 percent of the body is made of water. Every tissue, cell, and organ requires water for optimal functioning. Moreover, all bodily processes, from digestion to blood circulation, need water. Water is essential to flush out toxins from the body, carry oxygen to every organ, carry essential nutrients to all body parts, and maintain skin and hair health. Needless to say, there can be several side effects from not drinking enough water. Constant headaches One of the most common side effects of not drinking enough water is experiencing persistent headaches. This is because insufficient water causes an imbalance of electrolytes and fluids in the body. The fluid loss causes the tissues in the brain to shrink or contract. As the brain shrinks, it starts to pull away from the skull, putting pressure on the nerves. This is what causes the constant headaches. Constipation When sufficient water is in the body, the colon takes it from the bloodstream to the intestines. This is done to soften and bulk up the stools. However, when you don’t drink sufficient water, there is not enough for the digestion process to complete. As a result, the stool becomes hard, and there are motility issues since the hardened stool cannot pass through the system.