How important is hydration, really?

Most people focus only on nutrition and often neglect hydration. Dr. Tim Podlogar points out that a lot of attention should also be paid to proper hydration, which, together with nutrition, allows the body to perform optimally during training. In a conversation with Dr. Tom Kirk, he explains what problems can be caused by inadequate hydration, what to look out for when choosing a drink for exercise and why drinking water can cause problems.