Why Cold Weather Makes You Pee

Why Cold Weather Makes You Pee Does it seem like you have to pee more when youre cold or when its cold outside than when its warm? Its not just your imagination!   When you are cold, your body wants to protect your vital internal organs from the temperature change. It does this by constricting capillaries in your hands and feet through a process called peripheral vasoconstriction. Your extremities get cold, but toasty warm blood bathes your core. This means there is more blood in a smaller volume, which raises blood pressure, causing your brain to signal the kidneys to remove liquid from your blood. Your urine volume is increased and you need to urinate. In addition to the effects of vasoconstriction, cold temperatures change how permeable cells are to water. Proteins called aquaporins act as channels to allow water in and out of cells more quickly than through osmosis. When body temperature starts to drop, aquaporins limit the amount of water allowed into some cells, including kidney and brain cells. Less water going into cells translates into more water in the bloodstream. Here too, your brain tells your kidneys to remove the excess water, filling your bladder and making you need to pee. Is Drinking Alcohol a Good Way to Keep You Warm? If you drink an alcoholic beverage to feel warm, youll likely make the situation even worse. The alcohol will dehydrate you, in part because it also inhibits aquaporins. Alcohol acts as a diuretic, so your body thinks it needs even less water than it was holding onto before you took that first sip. Alcohol does make you feel warm but actually hastens hypothermia by expanding the capillaries. From this effect, youd need to pee less, but the continued drop in temperature would eventually lead you to pee more and could kill you from cold. Another factor to consider is perspiration. If youre cold, youre not losing moisture through perspiration. When its hot, youre slowly (or quickly) becoming dehydrated by sweating. If you feel cold, youre retaining water compared with when youre warm.