LD Asks: I am a 32-year-old avid runner. I have been training for a marathon that is coming up in two months. I have been training for a while for this run. How can I optimize my run and prevent dehydration during this long-distance endeavor?

Dr. Patel writes: Long-distance running can be accomplished only if the individual is well-hydrated. Our blood is comprised of cells, water, and electrolytes. When a person runs and sweats, they lose two main components from their body (water and electrolytes). Your body sweats to cool itself.

Dehydration can cause the body to shut off the sweating process which in turn can cause the core body temperature to increase. This can cause heat exhaustion and, in severe cases, heat stroke. Other signs of dehydration are headaches and decrease in urine output.

My recommendation would be first to load up on carbohydrates the night before to have good reserves the day of the run. Also, avoid caffeine and carbonated drinks, both of which can increase the rate of dehydration.

Drinking water alone will not be enough to rehydrate the body. Electrolytes are needed to replenish the body. A good source of potassium is a banana. Other excellent sources are Pedia-lyte and Gatorade. Drink plenty of fluids and pace yourself.