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The Mammalian Diving Reflex

The mammalian diving reflex is an involuntary response to cold water that causes the heart rate, breathing rate and blood pressure to drop. This low-stress state allows mammals (and humans) to conserve energy and oxygen while underwater. The diving reflex has been studied extensively in marine mammals like seals, whales and dolphins!

The mammalian diving reflex is considered advantageous because it helps reduce blood flow to non-critical parts of the body, such as our hands, feet and face — all areas that are not essential for survival during a dive. As a result, more blood flows towards parts of the brain that regulate vital functions such as breathing rate and heart rate so they remain steady while underwater

What Is The Mammalian Diving Reflex

The mammalian diving reflex is a physiological response to cold water that causes the heart rate and blood pressure to decrease. When the face or ears are exposed to cold water, this reflex is triggered, causing a number of changes in the body’s physiology.

The first step in the process is that your nerve endings send signals from your skin to your brainstem. The signals tell you that there is something cold on your skin and send signals for other parts of your body as well. In response, some muscles tighten up (like those around your face), while others relax (like those around other parts of the body). As a result, blood flow becomes restricted and redirected towards vital organs like the heart and lungs because they need more energy than other organs during times when you are under stress or facing danger (a common example being when someone makes eye contact while walking down an alley).

How Does The Mammalian Diving Reflex Work

The mammalian diving reflex is a way for your body to protect itself when under cold water. When you submerge yourself in freezing temperatures, your heart rate goes down, blood pressure increases and most nonessential functions shut down. These changes help keep you warm by slowing down circulation of oxygen-rich blood and preventing it from escaping as quickly into the surrounding water.

The mammalian diving reflex can save your life!

If you’re in danger of drowning, your body is going to do everything it can to keep you alive. The mammalian diving reflex is one of these mechanisms and it works by increasing blood pressure and heart rate—two things that help prevent oxygen deprivation after submersion.

The diving reflex also decreases blood flow to the skin, muscles and brain—minimizing the amount of oxygen that’s used up when you’re under water for long periods of time. And lastly, there’s an increase in breathing rate which helps keep your lungs full of air even if they were empty when submerged!

The Science Behind The Mammalian Diving Reflex

  • The brain is protected from pressure. As you descend underwater, your ears gradually fill with water and the outside pressure increases. To prevent your eardrums from rupturing, you must equalize the pressure in each ear by pushing air into them. This is accomplished using a process called the “mammalian diving reflex.”
  • The body is protected from cold. Your body’s core temperature drops when submerged in cold water—unless you have access to warm blood vessels near the skin surface (which most mammals have). Mammals also evolved a thick layer of insulating fat for warmth and buoyancy, which allows them to float without expending much energy or effort.
  • Oxygen levels are maintained at normal levels despite breath-holding ability being reduced by over 99%. Some mammals like seals can hold their breath for up to two hours! They accomplish this through their large lung capacity combined with an extremely efficient system of supplying oxygen-rich blood directly to heart muscles rather than first passing through lungs before returning them back again after being deoxygenated during breathing cycles.


The mammalian diving reflex is a fascinating phenomenon that has been studied by scientists for years. The fact that it can be triggered in humans means that there’s hope for those who suffer from conditions like hypothermia or drowning. In other words, if you’re ever in danger of freezing to death on land or going underwater without breathing equipment (like what happened to me when I went swimming in the ocean), just remember how important it is to have some water around!

If you ever find yourself in this situation—for example, if somebody tries to push you into cold ocean water and your instincts kick in or if you fall into an icy lake—the mammalian diving reflex may save your life.