Angiotensin II is a potent vaso-active peptide that causes blood vessels to constrict, resulting in increased blood pressure. Angiotensin II also stimulates the secretion of the hormone aldosterone from the adrenal cortex. Aldosterone causes the tubules of the kidneys to increase the reabsorption of sodium and water into the blood.
The most reliable record of a Blue Shark at speed is 24.5 miles (39.4 kilometres) per hour for a 6.5-foot- (2-metre-) long individual. The Shortfin Mako (Isurus oxyrinchus) is probably the champion speedster among sharks.
A swimmer with average skills can swim approximately 2 miles per hour. This is roughly equivalent to taking 56 seconds to swim the 50-meter length of an Olympic-sized pool.