Dehydration is not just a hot summer topic, even though runners typically associate sweating or feeling thirsty with warmer months. Dehydration can be a serious issue even in colder weather and inhibit performance, recovery, and basic bodily functions. From a physical standpoint, cold, dry air requires increased fluids to humidify the air as it enters the lungs, leading to higher fluid consumption. Additionally, the sensation of feeling cold can also inhibit thirst, even when the body requires these fluids. Although we might not feel the same need to drink in the winter, we may actually need to drink more than we think. Hydration, in any season, is essential for running success and is too often neglected during winter months.
Why dehydration is a concern for runners
Dehydration not only negatively impacts running performance but can be detrimental to maintaining overall health. The technical definition of dehydration is when individuals lose more fluids than they take in. This can be caused by underlying medical issues, sicknesses that induce vomiting, diarrhea, sweating, etc., or physical activities such as running that increase sweat rate and thus a loss of fluids (as well as loss of essential electrolytes in sweat). Symptoms of dehydration include dry mouth and tongue, dizziness, fatigue, dark-colored urine, sunken eyes and cheeks, cramping, and extreme thirst. For runners, such symptoms during training or competition can mean the difference between staying on pace or even finishing their workout or races.
Dehydration is diagnosed in both young and old populations of runners. Treatments for mild cases are as simple as rehydrating through increasing fluid intake for several days (as well as maintaining proper electrolyte balance in these fluids), while serious cases may require hospitalization and IVs. Activities that increase sweat rate, such as running, might increase your chances of getting dehydrated, but these symptoms can be easily avoided with proper hydration strategies.
Dehydration is not just a hot summer topic, even though runners typically associate sweating or feeling thirsty with warmer months. Photo by: Peter Maksimow
How to avoid dehydration as a runner
Due to the extreme impacts of dehydration and running performance, UESCA-certified running coach Cliff Pittman has developed strategies for his athletes to avoid getting dehydrated while training or racing. Pittman shares his hydration insights for trail/ultrarunners, “In the context of marathon running, a mild level of dehydration, roughly 2-3%, may not significantly impair performance. However, when it comes to ultramarathons, such dehydration could have dire consequences, potentially leading to a Did Not Finish (DNF) outcome or more severe health issues. Environmental conditions, including extreme heat, humidity, or high altitude, can exacerbate the risks associated with dehydration.
Various approaches to hydration exist, ranging from the ‘drink to thirst’ method to the ‘drink to schedule’ strategy. In my coaching practice, I typically advocate for a “drink to schedule” approach, contingent on a field test to determine an athlete’s hourly sweat rate. By comprehending the volume of fluid lost during activity at specific temperature ranges, we can target the replacement of approximately 90-95% of these losses, as opposed to striving for a full 100% replacement. While the ‘drink to thirst’ method may suffice in more temperate environments, adopting a more precise and structured approach based on available information becomes imperative in extreme conditions. One should never race Badwater with the plan of, ‘I’ll drink when I get thirsty.’ Nonetheless, athletes should remain adaptable and open to adjusting their hydration strategy as needed.
It is essential to recognize that hydration status also impacts various physiological processes, including digestion. Dehydration can hinder nutrient absorption and utilization. Therefore, for ultramarathon distances, regardless of the environmental conditions, proper hydration practices are of paramount importance to optimize performance.”
Dress properly for the weather in order to reduce sweating and the chances of dehydration. Photo by: Peter Maksimow
Dehydration can be a serious concern for your running and overall health, but it can be easily avoided in most instances with proper hydration strategies such as those from Pitman listed above. Recognizing the importance of hydration during all seasons (winter included) is especially important. Listed below are the most overlooked factors I’ve found that leave runners more susceptible to dehydration, especially during colder months when runners may not instinctively think they should be concerned with hydrating.
Pro tip: Want more coaching advice from Cliff Pittman? Read our article, Cliff Pittman On Science-Based Coaching. Connect with him on his coaching website here.
Winter Trail Running Hydration Tips
What you wear matters
Wearing layers is important to stay warm for winter running, but few runners realize how to do this properly in order to reduce sweating and the chances of dehydration (read out article What Should I Wear? How To Layer for Winter Trail Running for more on this topic). Wearing too many layers or materials that aren’t “moisture wicking” can cause excess sweating, sometimes even as much as during hot summer months. Additionally, the moisture on your skin draws heat from your body, forcing you to work harder to stay warm. Overall, dressing improperly not only increases your chances of getting cold but also dehydrates you by increasing your sweat rate.
Maintain electrolyte balance
Staying hydrated is about more than just drinking enough water. Proper hydration involves a balanced ratio of water and electrolytes—namely sodium and potassium. Having excess water in this ratio (hyponatremia) or excess sodium/electrolytes (hypernatremia) are both serious medical concerns that can lead to hospitalization in serious cases. Monitor your consumption of both salts and fluids. It can be tempting in winter months to drink large amounts of tea or other hot liquids, but make sure that your sodium/electrolyte intake matches this intake. Similarly, eating too many salty foods without drinking can also be problematic.
Proper hydration involves a balanced ratio of water and electrolytes. Photo by: Peter Maksimow
Understand the stresses of an illness
Winter months inevitably bring increased rates of colds and sickness. Trail runners often push through such illnesses or find ways to keep training for races despite the extra strain it places on their bodies. Although some physical activity during sickness may be beneficial for the immune system, running too much can overstress the body. If your sickness causes diarrhea, vomiting, night sweats, or you have other symptoms that cause you to lose fluids, you should be especially wary of running. Your body might already be in a state of dehydration because of your sickness, so if you choose to run, it should only be an easy effort, and you should also consider increasing your fluid intake.
Avoid excessive caffeine and alcohol
Caffeine and alcohol, or in more typical trail runner terms—pre run coffee and post run beer—can increase your risk of dehydration. Both caffeine and alcohol are mild diuretics, which, when paired with running, can cause fluid loss. Small amounts of these substances can be consumed without significant consequences, but be wary of multiple alcoholic drinks per day or heavily caffeinated energy drinks/“pre-workout mixes” that usually contain caffeine in unhealthy amounts. Completely eliminating these substances may be inconvenient or impossible for the majority of the running population, but limiting them or pairing them with hydrating drinks will help keep you healthy while training. Although I am not a proponent of N/A (non-alcoholic) beers or decaf coffee, these have been popular alternatives for those looking for ways to limit their consumption of alcohol and caffeine.
Carry what you need
I’ve seen more runners carrying hydration products in the summer months than in winter. Consider bringing water or electrolyte drinks with you on long winter runs. Extremely cold climates may even require that you utilize insulated water bottles so your fluids don’t freeze. Search for water bottles that are easy to hold with running gloves (I prefer those with hand straps), or wear running belts. Recognize that you might not feel as thirsty when running in the cold, but having fluids with you is an easy way to encourage yourself to drink and stay hydrated while running in colder temperatures. The more you consume liquids in colder weather, the better your body will be at recognizing thirst and the easier it will be to drink.
While increasing your hydration, make sure to keep your water bottles and hydration packs/reservoirs clean. Photo by: Peter Maksimow
Don’t overdo the heat and steam
Hot tubs, saunas, steam rooms, baths, hot yoga, etc., feel best when it’s cold outside. Although these hot therapies can be great for recovery or muscle relaxation after runs, you should be wary of how extremely heated and humid spaces can increase your risk of dehydration. If you choose to use hot therapy, make sure you are bringing enough liquids with you to replace your lost fluids and electrolytes. It’s common for runners to experience dizziness or poor training after hot therapy if they don’t properly hydrate before, during, and after these hot activities.
PROTIPS: Increasing your hydration also means you’ll need to keep your water bottles and hydration packs/reservoirs (such as HydraPak or Camelbak) clean. Consider using Bottle Bright, a cleaning tablet sourced with materials readily found in nature (free of harsh chemicals) that leaves no residue and cleans simply with no scrubbing or soap required.
ATRA Switchback member HydraPak also shares their tips for how best to maintain their products, “Our team has created a helpful Reservoir Cleaning Guide and Video that provides an in-depth overview of how to best clean and care for your hydration system. HydraPak also offers a replacement part program for all of their reservoirs that make it easy to swap out bite valves, update to a new tube system, or file a claim using the Beyond Lifetime Guarantee.”
