“Folks need to hydrate on a regular basis,” he told Katie LaSalle when talking about how to prepare for the race. “We already know that water composes most of our bodies… When you become dehydrated, your blood volume decreases.”
That could affect not only your running but your health.
“Your heart has to work extra hard to keep up, so it’s essential that you start drinking,” he added.
Castro says a good rule of thumb is to drink water once a day for every kilogram you weigh.
There are four aid and water stations along the BolderBOULDER course, but you will want to make sure you also drink plenty of water before the start of the race. We dehydrate faster in Colorado’s high altitude.
“The BolderBOULDER’s tough,” Castro added. “This is the toughest mass race in the world, so go in prepared. Trust your training. Hydrate properly. Have fun. Stay within your limits and if you want to race home, wait till the last third of the race.”