värisemine

Värisemine, also known as shivering, is an involuntary physiological response characterized by rapid, rhythmic contractions and relaxations of muscles. This process generates heat within the body and is primarily triggered by a drop in core body temperature, a condition known as hypothermia. When the body senses it is getting too cold, the hypothalamus, a region of the brain, signals the muscles to shiver. These muscle contractions increase metabolic activity, thereby producing heat to help restore normal body temperature.

Besides cold exposure, värisemine can also be caused by other factors. Strong emotions like fear or excitement can sometimes induce shivering due to the release of adrenaline, which can affect muscle activity. Certain illnesses, such as fever, are often accompanied by shivering as the body's temperature regulation system is reset to a higher point. Some medications or withdrawal from substances can also lead to tremors or shivering. In some cases, neurological conditions can cause involuntary muscle contractions resembling shivering. While typically a protective mechanism, persistent or severe shivering outside of cold conditions may warrant medical attention to determine the underlying cause.