Why You Feel the Urge to Pee More When It’s Cold Outside
Did you ever notice that you feel the urge to pee much more when the temperature decreases, when it’s really cold outside?
Well, it turns out that it’s something quite normal that happens to everyone and the explanation for it is rather physiological.
Body and water
To begin to understand this physiological phenomenon, the first thing to know is that the body has 2 main ways of eliminating excess fluid:
By sweat: Every day, the human body performs various functions that demand heat-producing energy. Also, warm weather and physical activities increase body temperature, so sweating works like a cooling system.
By urine: The water we ingest is absorbed by the digestive system and passes into the blood. From there, the excess fluid is captured by the kidneys and taken to the bladder to be eliminated in the form of urine.
The simplest conclusion we could get from this is that when it’s cold, we sweat less. So if there’s no sweat, the only way for the body to expel water is to urinate. Although this is true, the explanation is a bit more complicated than that and is due to the so-called cold-induced diuresis.
What is cold diuresis?
It’s the appearance of increased urine production when exposed to cold temperatures. You may have noticed that when it’s hot your body looks more bloated which is due to the retention of liquids. During winter, the opposite occurs: the body is contracted and doesn’t usually retain liquids.
As the temperature drops, the dilation of the body also decreases, contracts, and retains less fluid, which is why we generate more urine. The body reacts to the cold to protect itself, sending more blood to the core of the body where the organs are and decreases the flow to the extremities.
This causes the blood vessels to contract and increases the pressure (the same amount of blood in a smaller space) that is perceived by the kidneys which will now have the mission of releasing that blood pressure by eliminating the unnecessary fluids that end up turning into urine.
In fact, cold diuresis is quite common for underwater activities such as diving, since, in addition to facing low temperatures, divers undergo a change in pressure in the environment due to depth.