Winter in New England brings all sorts of wonderful things: cozy fires, warm slippers, and walking in fluffy white snow. But there are risks as well. We know all too well the dangers of slipping on ice or shoveling snow. In today’s article, I’d like to talk about a lesser-known winter risk: dehydration.
Why do we take in less fluid?
Less thirst
Often in colder weather, our sense of thirst is decreased and so we drink less.
Fewer bathroom trips
Many people deliberately drink less fluid because it is inconvenient to peel off layers to go to the bathroom.
How do we lose more fluid?
There is also a phenomenon called “cold-induced diuresis”, which means that we tend to excrete more water and sodium in our urine when the temperature drops (we also experience this during immersion in cold water). This diuresis occurs because the cold weather causes vasoconstriction (narrowing of the blood vessels) in our extremities to conserve heat. This in turn can suppress secretion of a hormone called anti diuretic hormone (ADH); as a result, our kidneys excrete more water and sodium via the urine when we are in a cold environment.
In addition, many people are not aware that they sweat during cold weather. In fact, we do sweat, but it evaporates more quickly in cold dry weather, so it may be less obvious. Indoor dry heat further compounds fluid losses through our breath.
So: less fluid in and more fluid out (through urine, sweat, and exhaled air) can add up to dehydration. This can strain our kidneys and impair our ability to regulate our body temperature (“thermoregulation”).
How can I tell if I am dehydrated?
Decreased urine output and darker urine color are clues to dehydration. Some people may feel thirsty, crave salty foods, feel fatigued, or experience dizziness / lightheadedness with standing up.
What should I do if I am dehydrated?
Severe dehydration
In cases of severe dehydration (fainting, altered consciousness, inability to keep down fluids), you should go to the nearest hospital for intravenous fluids.
Milder cases of dehydration can be treated safely at home with fluids and electrolytes (most importantly, sodium) by mouth. It is important to balance water intake with modest amounts of sodium.
The American College of Cardiology recommends that most adults limit sodium consumption to 1500 mg of sodium per day (about 2/3 teaspoon of salt).
While many people think they must restrict their sodium intake and increase their water intake, this is not entirely accurate - rather, we must think of sodium and water intake in terms of balance. Too much sodium is not good but too little can also be dangerous. Both water AND sodium are lost in our urine, stool, sweat, and respiration, and therefore we must replace BOTH. Our blood and every cell in our body is composed largely of salt water, and our kidneys maintain a precise sodium concentration.
How much sodium should I have?
If you follow a typical Western diet with processed foods and restaurant foods, you are probably ingesting plenty of sodium in your diet. However, if you are someone who mostly prepares food at home and avoids packaged foods, you may need to add a bit of salt to your diet to replace your daily losses.
You can simply add salt to your food or choose salty foods such as pickles and olives, or drink tomato juice (about 600 mg of sodium, or 1/4 teaspoon of salt per glass). Some people like to use electrolyte drinks such as Nuun tablets, LMNT, or Pedialyte. Whichever type of hydration you choose, make sure that you are aware of the importance of balancing fluid and electrolyte intake every day, not just in the summer months.
Stay safe this winter!
