Our bodies are clever organisms and when we're exposed to the cold they adapt accordingly.In cold weather, our body tries to maintain its core temperature with vasoconstriction.Usually as blood passes through veins near to our skin, the external temperature cools the blood which then moves through our body and lowers our core temperature.To avoid this, the body constricts blood vessels and capillaries in our extremities like fingers, toes, ears and nose, allowing less blood to flow through these areas.But now there's less space, although we still have the same amount of blood, so our blood pressure increases.It's thought that to avoid raised blood pressure but keep us warm, our bodies squeeze the small amount of water in the blood to re-balance this pressure, according to ScienceABC.As our blood pressure rises, an anti-diuretic hormone decreases, signalling the kidneys to extract this water from the blood and store it in the bladder, making us feel the urge to urinate.A full bladder also leads to heat loss, so our bodies will try to eliminate this extra heat-sucker as soon as possible.So next time you go for a drink and are faced with only outdoor tables, maybe try another bar if you don't want to keep running to the toilets.