"Water temperatures in this range do, in fact, cause physiological changes--one of which is known as the cold-shock response, a "series of reflexes that begin immediately upon sudden cooling of the skin following cold-water immersion." During this reflexive response, "blood pressure, heart rate, and the workload of the heart all increase, making the heart more susceptible to life-threatening rhythms and heart attack. Simultaneously," an online text explained, "gasping begins, followed by rapid and deep breathing. These reflexes can quickly lead to accidental inhalation of water and drowning. This rapid and seemingly uncontrollable over-breathing creates a sensation of suffocation and contributes to feelings of panic. It can also create dizziness, confusion, disorientation, and a decreased level of consciousness."