We tend to think of dehydration as a problem that can only occur in the summer, when the air is ripe with humidity and the sun is beating overhead. However, dehydration can plague runners at any time of year, including winter; in fact, runners may be even more at risk of suffering from dehydration in the winter due to decreased vigilance about the condition. Here’s what you need to know about how dehydration can impact your winter running routine:
- The Air is Drier: The air is drier in the winter, which in turn draws moisture away from the body. The drier air also causes sweat to evaporate faster, leaving the surface of the body. When sweat evaporates, it cools the body, which is great in summer, but can be problematic in winter. As the body works harder to keep the internal organs warm, it goes through more water, making it critical to replace these fluids during your run.
- Urine Production Increases: The reduced temperatures signal to the body that it does not need to conserve water, which can cause the body to produce more urine, a condition called cold-induced urine diuresis. As urine production increases, more water leaves the body, which can contribute to dehydration over time.
- You’re Still Sweating: Although it might seem like you’re not sweating as much in the winter, sweat is also less noticeable in colder temperatures because it evaporates into the drier air instead of staying on the surface of the skin. While you might not feel like you’re sweating much, if at all, water is leaving your body and needs to be replaced to avoid dehydration.
- Breathe In, Breathe Out: Water also leaves the body through water vapor in the breath. When you can see your breath in cold weather, what you’re actually seeing is water vapor exiting the body. As your breathing deepens and your heart rate increases, you’ll lose more water through your breath and may find that your mouth dries out quickly. Be sure to replace the fluids with some water or sports drink!
In general, runners should follow similar guidance for fluid replacement in the winter as they do in the summer to avoid dehydration. Plan to take in about 6 ounces for every 20 minutes of exercise. As with summer running, water should be fine for runs lasting less than an hour, while runs lasting more than an hour might require some electrolyte replacement in the form of a sports drink or gel. Enjoy the winter months and stay safe out there!