When humans inhale water, their vocal cords spasm and shut, trapping the water in their mouth or nose and causing asphyxiation. "If you get enough water in there rapidly enough, the muscles at the top of the airway will collapse," Callahan explained. When this happens, people appear to be choking and turn blue. They are actually suffering from oxygen deprivation due to the presence of excess water in their lungs. The water may enter through an accident bite or by submerging a face-down body in water. If you are not able to breathe, then you need help immediately. Seek out help for anyone who appears to be drowning by calling 911 or getting into a life jacket if available. Once removed from the water, remove any clothing that is restricting breathing such as a shirt with a constricting collar. People can survive with only their neck and head under water for several minutes. However, without immediate medical attention they will suffer from asphyxia. The more water that enters your lungs the greater the risk of asphyxia. Dry drowning is a rare condition where someone inhales enough water to cause distress but not enough to kill them. Dry drowning can happen when someone breathes in water during swimming pool cleaning or bathing activities. The trapped fluid could eventually lead to asphyxia if it is not removed. People at risk for dry drowning include those who have asthma or other respiratory diseases, infants, small children, and older adults.