It seems that all of these and not one stand out, is responsible for the apparent ability of a baby to ‘swim’
Let’s have a look at some of the basic facts surrounding these reflexes.
The Dive reflex occurs in cold water and actually occurs in all mammals (that’s why it is called the mammalian reflex). It causes the heart to slow right down (hence the name Bradycardic reflex) allowing the body to use less oxygen and conserve what is in the body for the vital organs and brain. Vasoconstriction occurs n the peripherals (Luenberger 2001) and a de activation of the breathing muscles such as the diaphragm and intercostal muscles. (Matt Ansay, Kristine Sliwicki, Brittney Kohlnhofer, Sarah Castillo 2011; Gooden 1994)
Studies have shown that the dive reflex is initiated even by immersing only the face (particularly the forehead) in cold water. The whole body does not necessarily need to be submerged.
Interestingly, the ‘dive reflex’ can also be initiated by blowing in a baby’s face. Many people have noticed that a baby ‘holds their breath’ when someone blows on their face however the baby actually takes a quick breath in. This is why it is commonly cited as a means to calming a distressed baby who is crying uncontrollably. It is also referred to as the ‘breathing reflex’ and is commonly used whilst conditioning babies to submerge when swimming.
Babies also have what is known as the ‘gag reflex’. This involves the epiglottis blocking the passage to the lungs which further adds to preventing the inhalation of water.
The swimming reflex is responsible for the baby displaying a ‘swimming’ action.
Water is a great medium for babies to have freedom of movement as they do not have to fight gravity in order to move. They can use the muscles in their arms, legs, back and torso in ways that they are unable to on land. When a baby is placed in water on their tummies, they will start to move their arms and legs in a swimming type of motion. This reflex will begin to disappear around the age of 6 months.
So now we have briefly discussed four reflexes. One (the breathing reflex) initiates a baby to take in a quick breath before submerging and the second (the dive reflex) prevents the baby from breathing under water, the third stops the baby from accidently taking in more water (the gag reflex) and the third (swimming reflex) allows the baby to develop strength in their swimming muscles by mimicking a swimming action.
Together, along with qualified instruction, babies are able to take part in reputable swimming classes designed to develop their muscular and cognitive function and assist then in developing water survival behaviours. It is important to realise that these reflexes should not be relied on to save a baby from drowning and parents should ALWAYS remain vigilant with their supervision when their baby is around water.