Summary
Highlights
Short-duration cold application excites muscles and facilitates muscular activity, useful for pre-activity stimulation. Brief, repeated stimulations can increase muscular power. However, prolonged and intense application leads to muscle relaxation, not contraction.
Cryotherapy initially causes vasoconstriction, followed by vasodilation as the body tries to rewarm the area. Intense cold can constrict deep blood vessels and arteries. On the cranium, it causes sudden dilation, then vasoconstriction, followed by slow vasodilation to ensure sufficient oxygen supply.
Cold stimulation in the precordial area decreases heart rate. Primary vasoconstriction elevates blood pressure, so caution is advised for individuals with high blood pressure, though it may later decrease due to reactive vasodilation.
Cold initially provokes a deep inhalation, followed by a pause and a long exhalation. This response, often observed when cold is applied to the occiput and neck, is the body's reaction to assimilating the cold.
Cryotherapy increases leukocytes and blood viscosity, slowing blood flow. It also raises hemoglobin levels and red blood cell count, though these changes are typically not extreme.
Cold exposure increases diuresis (the need to urinate) due to its action on renal circulation or direct bladder stimulation. This effect makes cold useful when increased diuresis is desired. Albumin elimination in urine can also occur.
Brief cold applications have an exciting effect on both the central and peripheral nervous systems. Prolonged application (over 15 minutes) can lead to anesthesia in the treated area. It reduces functional capacity, alters cutaneous reflexes and sensitivity, and affects nerve conductivity.