On a hot summer day, when the sun is blazing and the sky is completely cloudless, beads of sweat on your forehead encourage you to ensure that you are consuming enough water. This is especially true when you’re doing hard physical work or exercise outdoors – because your body loses water much faster. The dehydration of the body, which stimulates the thirst when the weather is hot, do not call for the same response when the temperature drops. This is not just because you feel cold, it is because the cold temperature impact thirst perception.
Getting the right balance of fluids in the body depends on thirst stimulation. When you feel thirsty, you drink fluids voluntarily – and will keep the kidneys or urinary fluid as necessary. This process is easier fluid controlling hormones, like AVP (Argentine plasma vasopressin), and a couple of things can stimulate these hormones. When your body loses water, the level of sodium in the blood and increases blood volume reduces overall as well. Both of these reactions stimulate the hypothalamus to their AVP, which makes the kidneys produce urine slowly. This revitalized hydrated. Simultaneously, the hypothalamus sends signals to the cortex of the brain, to create a sense of thirst – encourage the consumption of water required to restore healthy salt levels.
When the weather is cold, thirst response of the body is reduced by up to forty percent, even if you are suffering from dehydration. This happens because the blood vessels tighten when you are cold, to stop the blood from traveling easily to the periphery of the body. This makes the body retain warmth, by attracting the middle of the ‘extra blood.
However, because of this, your body is ‘tricked’ into believing that it is properly hydrated. The brain will not pay decrease blood volume, so the AVP hormone is not drained at normal speed – despite the increased level of sodium in the blood. Consequently, your body will not retain water and you will not feel particularly thirsty. This is why athletes tend to drink less water when training in cold weather. Also, do not receive their kidney hormone marker to preserve water, urine output increases. This condition is known as cold-induced urinary diuresis.
There are a few other things that can cause dehydration in the winter too. In cold weather, you lose more fluid through the respiratory process. For example, when your breath is visible, which is actually water vapor loss from the body. If you exercise vigorously extremely cold, you will lose a lot of steam when you breathe.
Insulated underwear, thick coats and other winter clothing items can help the body retain heat. However, the extra weight also means that your body needs to work 10-40 percent harder. Therefore, it generates more sweat – leading to loss of fluid. In cold air, the sweat evaporates much quicker. Often, this makes people wrongly believe that they are not sweating in cold conditions. This can cause decreased thirst sensation.
Revealingly, animals such as dogs and rats also show my thirst perception in colder weather. Usually, they drink back the lost fluids though. They also tend to experience an increase in central blood volume, due to cold-induced vasoconstriction.
It is important to drink plenty of water, especially when doing exercise outdoors in cold weather. You can check by examining urine to see if you are properly hydrated – it should have a clear color. In addition, you may be dehydrated if the lips and mouth become dry, if the skin is rinsed or if your saliva thickens. Severe symptoms are muscle cramps, abdominal and chest pain, sickness, dizziness and confusion, dimmed vision and raised pulse. You need to consult a doctor immediately if you experience any of the above symptoms of dehydration, but more importantly, stay hydrated to avoid them completely.