Chew on This

Is driver dehydration causing our bad driving?

DRINK UP: Keeping hydrated with water while at the office can help you stay alert for your commute home.
DRINK UP: Keeping hydrated with water while at the office can help you stay alert for your commute home. Miami Herald Staff

Miami drivers have the well-deserved reputation as among the worst in the country. And most people who have driven here think we are moving toward Hall of Shame status. But browsing through this week’s nutrition research I stumbled upon what might be one of the reasons. A study from the UK examined the impact of mild dehydration, which they called hypohydration, on driving errors.

Twelve healthy experienced drivers put the pedal to the metal in a simulated road test. For two hours they drove on a monotonous highway with curves, slow-moving vehicles, and road debris. During one test period they were well hydrated and in the other they were minimally dehydrated.

In both conditions, hydrated and dehydrated, driving errors increased the longer they drove on the monotonous road. These included lane drifting, late braking and hitting road debris. During the hydration period, there were 47 incidents; in the dehydrated test condition, there were 101. Driving while even mildly dehydrated doubled the driving errors. That is significant and leads me to believe everyone in Miami is dehydrated.

Water accounts for 40 to 60 percent of body mass and maintaining water balance is essential for health. Mild hypohydration can cause headaches, weakness, dizziness and fatigue. A 2 percent reduction in fluid status can cause cognitive impairment. Situations that increase the risk for hypohydration are heat, humidity, prolonged physical activity, certain medications, being elderly and limited access to fluids. Many of my patients tell me that they don’t think about drinking during the day and might not have anything until they get home. This could lead to a mild dehydration.

Keeping a bottle of water visible at work is an easy reminder to keep drinking. Stopping for a few sips at a water fountain, drinking the entire glass poured at a restaurant or starting the morning with warm water with lemon are just a few ways that could make you a better driver.

Sheah Rarback is a registered dietitian on the faculty of the University of Miami Leonard M. Miller School of Medicine. Follow her on Twitter @sheahrarback.