Final answer:
Immersion hypothermia is caused by exposure to cold environments for extended periods, leading to a dangerous drop in core body temperature, which can be fatal. Sunglasses do not prevent hypothermia; they protect against UV radiation.
Step-by-step explanation:
Longer-term immersion in cold environments may lead to immersion hypothermia, which is a dangerous decrease in core body temperature below 34.4 degrees Celsius (94 degrees Fahrenheit). Hypothermia occurs when the body's physiological processes that maintain a stable temperature are overwhelmed by the external cold. The body initially responds to cold by shivering and increasing the breakdown of stored energy to generate heat. However, if exposed long-term and without proper protection or warmth, these responses are not enough, and the core temperature can drop significantly. This leads to serious complications, as red blood cells lose their ability to release oxygen, causing confusion, lethargy, and eventually a loss of consciousness and possible death.
It's important to note that wearing sunglasses does not prevent hypothermia. Sunglasses protect the eyes from UV radiation, preventing cataracts and immune suppression but have no direct effect on the body's core temperature. To prevent immersion hypothermia, appropriate clothing and exposure management are required, not eye protection.