Instinctive Drowning Response
The instinctive drowning response is a set of behaviors automatically undertaken by a person who either is, or is very close to, drowning. They are autonomic responses of the body, triggered by the sensation of suffocation in water.
Contrary to the normal popularisation of drowning as a highly visible behavior, involving shouting, abrupt or violent movements such as splashing and waving, and visible difficulty — which is a related phenomenon, known as aquatic distress, which often but not always precedes drowning — the instinctive drowning response is noiseless and confined to subtle movements.
While distress and panic may sometimes take place beforehand, drowning itself is quick and often silent. A person at, or close to, the point of drowning is unable to keep their mouth above water long enough to breathe properly and is unable to shout. Lacking air, their body cannot perform the voluntary efforts involved in waving or seeking attention. Involuntary actions operated by the autonomic nervous system involve lateral flapping or paddling with the arms to press them down into the water in the effort to raise the mouth long enough to breathe, and tilting the head back. As an instinctive reaction, this is not consciously mediated nor under conscious control.
The lack of leg movement, upright position, inability to talk or keep the mouth consistently above water, and (upon attempting to reach the victim) the absence of expected rescue-directed actions, are evidence of the condition.
The instinct takes place for typically no longer than the final 20–60 seconds during drowning and before sinking underwater. In comparison, a person who can still shout and keep their mouth constantly above water may be in distress, but is not in immediate danger of drowning compared to a person unable to do so.
To an untrained observer, it may not be obvious that a drowning person is in distress — they may appear to be swimming safely while within 20–60 seconds of sinking under the surface. They extend their arms laterally and press down on the water's surface in order to lift their mouths out of the water. When their mouth is above the water, they quickly exhale and inhale instead of calling for help. Because of their arm movements and their focus on lifting their mouth out of the water, they cannot wave, kick their feet, nor swim to a rescuer, nor grasp a rope or other rescue equipment. They may be misunderstood as "playing in the water" by those unfamiliar with drowning, and other swimmers just meters away may not realize that an emergency is occurring.
Lifeguards and other persons trained in rescue learn to recognize drowning people by watching for these instinctive actions.
In emergency situations in which lifeguards or other trained personnel are not present, it is advisable to wait for the victim to stop moving or sink before approaching, rescuing, and attempting to resuscitate. While the instinctive reaction to drowning is taking place, victims latch onto any and all solid objects in attempts to get air, which can result in the drowning of a would-be rescuer as well as the victim. The effect called 'AVIR Syndrome' (Aquatic Victim Instead of Rescuer) has killed over 100 would-be rescuers in Australia and over 80 would-be rescuers in New Zealand. In Australia, 86 of these rescuers who drowned were trying to rescue children, and they had failed to follow basic rescue safety rules that are easily learned.
Research and discovery
The common drowning behaviors were identified by Frank Pia based upon study of film footage of actual and near-drownings, and documented in his 1971 instructional film On Drowning, and a 1974 paper Observations on the drowning of nonswimmers.
At the time, it was commonly believed that drowning involved agitated behaviors, although Pia cites an earlier (unspecified) 1966 paper as also observing this was not necessarily the case.