Dehydration in Colder Weather: What Athletes Should Know

February 03, 2020

Brittney Lang MS, ATC
Athletic Trainer

It is winter time here in the south and though we don’t necessarily get extreme frigid temperatures or snow often, we can get cold temperatures which can bring with it risks for our adolescent athletes who practice and play outside. The weather during the winter months can fluctuate between warm and cold fairly easily, especially once the sun sets. There can be many factors to consider when the athletes are practicing or playing in these colder temps but a major one is risk of dehydration. Dehydration is usually more seen as a concern during higher temperatures but athletes are just as much at risk or greater in colder temperatures. Our body loses fluid through exhalation, perspiration, and urination.

When training in the heat our body sends triggers to the brain that one is thirsty and should drink. It has been determined that the body’s fluid-regulating hormones that stimulate thirst and conserve bodily fluids is reduced by almost 40 percent in colder temperatures. Young athletes already tend not to hydrate themselves properly to begin with so when the weather is colder they tend to drink less during physical activity and increase the risk of dehydration.

During exercise and physical activity athletes sweat and during hotter temperatures the sweat is more visible and helps give the athlete a kind of visual cue to drink more fluids. In the cold, athletes still sweat just as much but the sweat tends to turn to vapor in cold, dry air so the athlete does not have those cues and hinder them from hydrating properly because they do not think they need it as much. The athlete needs to know they need to hydrate no matter what.

Another form of fluid loss is just through breathing. In cold and dry air our bodies have to work harder to warm up the air we breathe by humidifying it with water in the body. The harder the body works, the more water we lose the more we have to hydrate. We can see some of this water from the body in the form of vapor when the athlete can see their breath in the cold dry air. This contributes to major fluid loss in the body.

A final way one’s body loses fluid is through urination. This is very well known with athletes but this can also tell an athlete how well they are hydrated or not. What may not be known is that in colder weather blood vessels are constricted and moved from the extremities to the core of the body to maintain proper body temps. This can make the body seem as though it is hydrated and not signal to the kidneys to conserve fluids. This in turn causes the body to increase urine output and leading to possible dehydration. If an athlete is taking in enough fluids they should be expelling a normal amount as well. If they are not urinating proper amounts that means the body is not getting enough to replenish what it needs. The color of the urine is also a major factor in determining if the athlete is properly hydrated. Having a urine color chart easily accessible for the athletes to use is very beneficial and allows the athlete to continuously assess their hydration needs. The urine should ideally be a pale yellow and if it is darker the athlete is dehydrated and needs to replenish their fluids. If urine color is very darker yellow or even brownish than they are severely dehydrated and needs proper medical attention right away. The athlete is likely showing other signs of dehydration as well at this point.

Early signs of dehydration:

  • headache
  • nausea
  • dizziness
  • fatigue
  • weakness
  • muscle cramps

If the athlete is showing signs and symptoms of dehydration it should be addressed as soon as possible because it could lead to further medical issues.

There are ways to combat dehydration in colder weather. Listed are some ways to help reduce dehydration in colder weather:

  • Replenish what you lose: Drink fluids to match what you are losing throughout the whole day. When you drink less than what the body needs, you are already at risk of being dehydrated. You can monitor hydration levels by the color of one’s urine.
  • Hydrating to the activity level: If an athlete is only active for up to an hour proper water intake should be sufficient for hydration. If exercises is longer than an hour or more intense than adding a sports drink or fluids that included electrolytes and carbohydrates for hydration is beneficial.
  • Eating fruits and other hydrating foods: Many fruits are great sources of water. Having certain fruits as snacks throughout the day will help in keeping the body hydrated. Eating soups or broths are also good choices for staying hydrated.
  • Choosing the proper temperature drinks: Cold fluids are absorbed by the body quicker and can be fine during mild dehydration or more rigorous activity. The athlete should try to drink smaller amounts as well, so as to limit the possibility of getting sick. If the body is cold and possibly shivering drinking warmer drinks will help aid the body in regulating the core temps and will help to warm you up. So if one is very cold drinking hot chocolate after exercise can actually be good for the body. Not only does it warm the body up but chocolate milk has been shown to have a 4:1 carbohydrate to protein ratio making it a good recovery drink post exercise.
  • Avoiding caffeine: Caffeine has a diuretic effect. It will cause you to lose more fluids because it can promote increased urine output.
  • Wearing layers: wearing layers of clothing helps to regulate the body temperature. When the body is cold and it is working hard to keep the body temps regulated it puts more work on the heart trying to pump the blood through the body dehydrating you more. By layering up with proper clothing this will help to absorb sweat and trap body heat in keeping the core temperatures stable.

It is important to let the athletes know that dehydration greatly affects their physical output and endurance during sports. It increases muscle fatigue and can lead to higher risk of injury during physical activity.  When an athlete is dehydrated it affects every aspect of their body and its performance. Properly hydrated, the athlete is able to perform at their highest ability and allows for better recovery afterwards. Hydration is key all year long, during hot and cold months. It is our job to instruct our athletes on proper ways to maintain hydration levels and be aware when they may be at risk for dehydration.

About the Author

MUSC Health Sports Medicine

Keywords: Sports Medicine