Can blood clot underwater? © Getty Images

Can blood clot underwater?

Our reactive healing processes aren't easily prevented but clotting might take a little longer when important clotting factors are being washed away.

Asked by: Anonymous


A blood clot isn’t just your leaking blood drying out, or even a chemical reaction that happens on contact with air. If it was, we would all bleed to death from the slightest internal injury, and waterproof plasters would prevent a scratch from ever healing. Blood clotting is an active, biological response that is triggered by damage to the wall of any of our blood vessels. First the muscles around the vessel contract to slow the flow of blood there. Next tiny blood cells called platelets attach themselves to the injury site and begin clumping together. This clump is reinforced with strands of a structural protein called fibrin. Other proteins crosslink the fibrin strands to harden the gelatinous plug. All of these processes will proceed perfectly well underwater but because water is dense and a good solvent, fast flowing water might wash away the clotting factors before a stable clot can form on an external cut.


Subscribe to BBC Focus magazine for fascinating new Q&As every month and follow @sciencefocusQA on Twitter for your daily dose of fun science facts.