Have you ever wondered why you don’t get thirsty on winter hikes even though your pee turns yellow and it’s clear that you need to drink more? Blame your brain. It’s not wired to recognize the increased amount of water vapor you expel in your breath when the air is cold and dry, or added perspiration when you wear insulated clothing. That’s why it’s important to drink lots of liquids on winter hikes, even though your brain is telling you that you’re not thirsty.
Vasoconstriction in the Cold
There’s also physiological reason why you don’t get thirsty in winter. When it’s cold, your body decreases the amount of blood it sends to your periphery to decrease heat loss, a process called vasoconstriction. Your brain, however, doesn’t perceive a blood volume decrease that would normally trigger your “thirstiness reflex.” Instead, it thinks you’re well hydrated because there’s an increased amount of blood in your core. So do your kidneys, which think you need to relieve some of your extra blood volume, which is why many people pee frequently on cold weather hikes. The net effect is less fluid intake and more fluid loss, resulting in eventual dehydration.
Winter Water Bottles
There’s a second reason you don’t drink enough in winter and that’s because the entire process of winter hydration is so different from the rest of the year. For instance, you can’t use a hydration reservoir because the hose will freeze up. You also can’t carry a thermos for the 2-3 liters you need because it’ll be too heavy. Instead you need to boil your water in the morning and pack it into wide mouth bottles which you store upside down so the lids won’t freeze shut. You can then pack them in insulated foam covers that clip to your hip belt or cover them with wool socks and store them in your pack, so they will stay liquid for most of the day.
Often, peer pressure works against you too. Drinking from a water bottle in winter often requires a stop, so you can pull a water bottle out of your pack. Doing this can be intimidating in a group, especially when everyone is in a hurry to get somewhere and considers stopping to be a delay or a sign of poor conditioning.
The Taste of Hot Water
Hot water is not that appetizing to drink, so it helps if you can flavor it to make it more palatable. This requires a bit more preparation time when you’re boiling water in the morning, but it is worth it. My favorite additive is Bengal Spice Tea, a caffeine-free interpretation of chai tea that has a sweet cinnamon and clove taste without any added sugar (3 bags per liter). I also like to drink a spicy sweetened ginger drink (3 bags per liter) which gives me a little pick up, from the included honey and sugar.
It helps if you can quickly boil water at home, so you can take a full 2-3 liters with you for an all-day hike. I’ve found that an electric Secura kettle is the fastest way to boil water, and faster than a gas or electric stove – which is helpful if you’re boiling water for a group.
Tips and Tricks to Stay Hydrated in Winter
- Boil your water before hikes and store it in a bottle holder insulated with foam or neoprene.
- Store your bottles upside down so the caps don’t freeze shut.
- Use wide mouth bottles, so the necks don’t freeze.
- Flavor your hot water to make it more desirable to drink.
- Drink one liter of water, Gatorade, or other liquid in the car on the way to a winter hike.
- Clip an insulated bottle holder onto your hip belt so you can control when you drink and not be dependent on group stops.
- If your urine is yellow or brownish and not clear, you need to drink more water.
- Try to drink one liter every two hours. The goal should be to consume all your water on winter day hikes and have none left over.