### Human:\ncan the als challange cause an undiagnosed heart condition to appear?\n\n### Assistant: well i'd sure like to hear the backstory on this one. you're referring to the als association "ice bucket challenge " i presume? the one where people pour a bucket of ice water over their heads and donate money to the als association? if that's what we're talking about then i would cautiously answer your question with a "no " while also stating i'm not a doctor and cannot give medical advice. i'm betting you're asking this question because someone poured a bucket of ice water over their head and then fainted. this would not be uncommon and i'm surprised we haven't heard of it happening before. why would dumping a bucket of ice water over your head possibly cause you to faint? it's called " the vagal effect. " dunking your face in icy water causes your heart rate to suddenly slow way down. this is often referred to as the "diving reflex. " if the heart rate slows suddenly you can pass out. usually this lasts for only a few moments. it is not an indication of an underlying heart problem. interestingly you can also faint by holding your breath and bearing down hard to push out a bowel movement -- another way to suddenly slow your heart rate down. think about that before you try to rush your bowels in the bathroom next time. wishing you well!