The Diver's Superpower - The Mammalian Diving Reflex
Ever heard of the mammalian diving reflex? It sounds like something a superhero might have, but it's actually a completely natural response your body has to cold water, helping you stay underwater for longer periods.
This diving reflex isn't limited to just humans - aquatic mammals like dolphins, seals, and otters use it all the time! You'll even find it in penguins and, of course, us humans.
So how do we activate this superpower? It's actually quite simple. The water needs to be colder than 21°C (69.8°F) and come into contact with your face. When this happens, the sensitive nerves in our nasal cavity send a signal to our brain to trigger the diving reflex. Afterward, up to three remarkable things can occur:
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Your heart starts beating slower - in fact, it can drop by 10 to 25 percent! That might sound dramatic, but it's nothing compared to seals, which can experience a heart rate drop from 125 beats per minute to just 10!
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Blood supply to your arms and legs is restricted. This means you might start to feel numbness in your fingers and toes.
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During extremely deep dives, the body can allow fluid to flow freely through the chest cavity, helping to evenly distribute pressure so your organs don't get compressed.
Although I've never conducted a scientific experiment with this, I'm convinced that I would experience a drop in my heart rate if I submerged my face in cold water. And it's not just useful underwater. Have you ever splashed cold water on your face to wake up or relax? That's the diving reflex in action!
In fact, we also use this diving reflex in our training of veteran divers - these war veterans quickly discover that something shifts in their mindset as soon as they get their heads underwater. Jan Laurenbor Olsen, chief instructor for the veteran school, states this.
So the next time you dive into cold water, remember your built-in superpower. Science isn't just fascinating - it also has practical benefits for us divers.
Use diving gear - Dive Equipment