Drowning is defined as respiratory impairment from being in or under a liquid. It is further classified by outcome into: death, ongoing health problems and no ongoing health problems. Using the term near drowning to refer to those who survive is no longer recommended. It occurs more frequently in males and the young. Drowning itself is quick and silent, although it may be preceded by distress which is more visible. A person drowning is unable to shout or call for help, or seek attention, as they cannot obtain enough air. The instinctive drowning response is the final set of autonomic reactions in the 20 – 60 seconds before sinking underwater, and to the untrained eye can look similar to calm safe behavior. Lifeguards and other persons trained in rescue learn to recognize drowning people by watching for these movements. Unintentional drowning is the third leading cause of unintentional injury resulting in death worldwide. In 2013 it was estimated to have resulted in 368,000 deaths down from 545,000 deaths in 1990. It accounts for 7% of all injury related deaths (excluding those due to natural disasters), with 96% of these deaths occurring in low-income and middle-income countries. In many countries, drowning is one of the leading causes of death for children under 12 years old. For example, in the United States, it is the second leading cause of death (after motor vehicle crashes) in children 12 and younger. The rate of drowning in populations around the world varies widely according to their access to water, the climate and the national swimming culture.