The Mammalian Dive Reflex
This tool is a new addition to my kit. I’m taking advantage of a reflex, common in all humans and easily triggered, to reduce my blood pressure and heart rate without the need for conscious thought.
I’ve used two different setups to activate this reflex, and so far I’ve been surprised at the effectiveness. Before taking you through the how, let’s explore the mammalian dive reflex and why it can help relieve anxiety.
The clearest explanation I’ve found is from The Mount Sinai Emergency Medicine website.
[The Mammalian Dive Reflex] is a cardiovascular reflex first noticed in oceanic mammals, specifically seals, that frequently undergo deep dives to cooler depths. The purpose of the reflex is two fold:
To increase the efficiency of oxygen consumption by decreasing the heart rate.
To redirect blood flow through peripheral vasoconstriction.
[In humans] The reflex is mediated by trigeminal nerve temperature receptors in the face. […] The trigeminal nerve sensory nucleus then activates the vagus nerve in the medulla leading to increased vagal tone on the heart with and slowing of AV nodal conduction.
Translation? When the human body is exposed to an environment resulting in apnea, a temporary cessation of breathing, it responds by reducing the energy needs of your body.
Blood is shunted to your core.
Heart rate drops.
Metabolism is reduced.
By slowing your system down, your body reduces the need for oxygen while you have a limited supply of it. You’ve done this in your car anytime you avoided revving the engine while your gas tank was low. There is no sense in quickly burning fuel if there isn’t much around.
A panic attack is your mind pressing the gas pedal of your metabolism to the floor. Your heart races, blood thunders in your ears, and you feel energy cycling endlessly through your body. It is nice to be able to experience the opposite sensations of a steady, rhythmic heartbeat and a ratcheting down of excess energy. See the videos below to see how I, and some others, trigger those calming sensations through this reflex.
A note before continuing: One of the methods I demonstrate requires breath holding for 40-60 seconds. If you do not feel comfortable, mentally or physically, attempting a breath hold of that length, then the second method is a better alternative.
Two Methods
In this video, I show different ways of triggering the mammalian dive reflex.
The first is submerging my face in cold water.
The second is pressing a bag of ice, or cold compress, to my face.
I hope you enjoy me being a guinea pig!
Ice-cold water
103 beats per minute - starting heart rate
47 beats per minute - after 20 seconds
Cold tap water in the sink
75 beats per minute - starting heart rate
54 beats per minute - after 20 seconds
41 beats per minute - after 1 minute and 20 seconds
For folks who like studies, here are a few relevant ones: