Video Credit: YouTube.com

What happens to your heart when you dive?  Some scientists in Pretoria, the capital of South Africa, had that same question.  Naturally diving animals like seals or dolphins have a mammalian diving reflex; this causes their heart rate to significantly decrease allowing them to use up less oxygen and stay underwater for longer.  What about humans though? 

P.G. Landsbug and the University of Pretoria did a study and found that the human heart rate can drop down to around 20 beats per minute, that’s just one time every three seconds! This means that we have a natural ability to explore the underwater world for extended periods of time!