törst

Törst is the Swedish term for thirst, the physiological sensation that motivates an organism to drink fluids. It is a central component of fluid balance in humans and other mammals, arising when the body’s water balance is challenged by dehydration, salt gain, or fluid loss.

Physiology and regulation: Thirst results from signals that reflect body fluid status. Osmoreceptors in the hypothalamus detect increased plasma osmolality, triggering the conscious urge to drink. Baroreceptors and other sensors respond to decreased blood volume or pressure, reinforcing thirst and promoting the release of vasopressin (antidiuretic hormone) to conserve water. Drinking reduces osmolality and helps restore blood volume, thereby dampening the thirst sensation.

Types of thirst: Osmotic thirst occurs with higher salt concentration or water loss, making the body seek fluids to restore proper osmolality. Hypovolemic thirst follows a significant loss of fluids and blood volume, such as through heavy sweating, vomiting, or bleeding. Both forms engage similar neural pathways, but their triggers—solute balance versus circulating volume—differ.

Brain and behavior: The hypothalamus plays a key role in detecting internal cues, while conscious awareness of thirst involves cortical areas such as the insula and orbitofrontal cortex. The act of drinking is a voluntary behavior that integrates physiological signals with environmental and behavioral context.

Clinical aspects: Abnormal thirst can indicate health issues. Polydipsia refers to excessive thirst, which may accompany diabetes mellitus, diabetes insipidus, or psychiatric conditions. Dehydration can occur from insufficient intake or excessive losses and requires assessment of fluid and electrolyte status.

Cultural note: In Swedish usage, törst is not only a physiological term but is also used metaphorically to express longing or desire.