Try this. Immerse your face in cold water and watch your heart rate plummet

So just tried this. Immersed my face in a sink of cold tap water. Programmed my Apple Watch to read out my live heart rate readings. Resting HR = 89, after immersion immediately plummeted to 61 then carried on dropping as far as 53. Not sure if this is the "master switch of life" as per the TED article author but definitely worth a try. May upload binary to Github. Can anyone think of any cool APP-lications for this? http://ideas.ted.com/science_of_freediving/