Winter Dehydration: Is It Real?

Dehydration Facts: Can You Really Get Dehydrated in Winter?

Anyone who has lived through a Colorado winter comes to know that they need two staples to make it through until spring: lots of lip balm and gallons of moisturizing skin cream. Although Colorado air is dry all year long, it gets a whole lot worse in winter and the effects that has on us are, while mostly annoying, can also have real health consequences.

First, let’s consider why it's so dry here.

What Causes Dry Air in Winter

Humidity refers to the amount of water contained in the air and is principally impacted by two factors: atmospheric pressure and temperature. As atmospheric pressure rises, more water molecules can be absorbed into the air, so it can be more humid. Similarly, at higher temperatures, the air is capable of holding more water and so higher humidity is generally seen.

In Denver, the higher altitude is associated with lower atmospheric pressure and temperature, so relative humidity is lower as well. The situation is even worse in the mountains to the West. In the spring and summer when it is warmer, the higher temperatures bring more humidity but never to the level seen at sea level because of the much lower atmospheric pressure that we have at altitude.

Dehydration Symptoms

In the winter when air temperature drops, our already low humidity plummets and the air becomes very dry, leading to the kinds of problems most Colorado residents have become familiar with:

• bloody noses
• very dry skin
• chronically chapped lips

The use of forced air heating in our homes makes the situation worse as this process tends to dehumidify the air even more.

A health effect that most people don’t think of as being a concern in winter is dehydration, but because of the very low humidity, it can actually be pretty significant. We usually see clinically important dehydration during the warmer summer months when people lose body water because of excessive sweating. However, during the winter months, it is not uncommon for people to become mildly or moderately dehydrated because of less obvious water loss and inadequate water replacement.

The very low humidity in the air tends to worsen loss of water in the breath. Dry skin is also less efficient at retaining moisture, so more water is lost. Sweat evaporation is also very rapid in low humidity environments so even though sweat rate is lower during the winter months, the amount of water lost can still be important.

Finally, the cold tends to diminish the thirst reflex, resulting in less of an impulse to drink than when it is warm. All of these factors combined can lead people to be chronically dehydrated during the long winter months.

Dehydration Treatment and Prevention

There are several things that you can do to help prevent getting dehydrated in the winter:

• Humidify the environment: The use of whole home or portable room humidifiers can help boost the humidity indoors and reduce water losses through evaporation.
• Heal the skin through the use of moisturizing skin creams.
• Stay adequately hydrated. Drink water continuously through the day and more when exercising.

Being aware of the dehydrating effects of our high altitude environment is the first step in taking measures to keep yourself healthy and hydrated until spring.

Jeffrey Sankoff, M.D., is an emergency medicine and critical care physician for both adults and children at Denver Health. Check out his podcast, the TriDoc Podcast, where he offers a fresh take on all things triathlon with a special focus on health and wellness topics.