Why do I urinate more in the cold?

Why do people urinate more in the cold? We went to Dr Matthew Mason from the Department of Physiology, Development and Neuroscience at the University of Cambridge to find out the answer to this pressing question. Matthew - This phenomenon is known as cold diuresis, diuresis being the production of more dilute urine. The idea is that when it's cold, your body tries to conserve heat by constricting the blood vessels in the skin. That means that less heat is lost to the environment. However, if you constrict the blood vessels to the skin, it means that relatively more blood accumulates in the interior of the body and that tends to raise blood pressure.

Khalil - A good way to imagine this is as if constricting blood flow in one part of the body squeezes the blood into other parts, just like if you squeeze a balloon at one end, the other end bulges out.

Matthew - In response to raised blood pressure, the body wants to try to get rid of a little bit of the water in the blood to bring the blood volume, and thus the blood pressure, back down to where it should be.

Khalil - This response prevents your body from being damaged by excessively high blood pressure, just like a safety valve on a boiler.

Matthew - What happens is that in response to the raised pressure, the levels of a hormone called anti-diuretic hormone will fall. With reduced anti-diuretic hormone, the kidney produces more dilute urine and that translates to an increase in urine production.

Khalil - What a relief! Next time, Claire asks if our furry friends are giving us more than just love and affection.

Claire - I'd like to know what parasites you can catch from your pets.