A water stop is a break and a place to break for drinking water

Water

Water is a chemical substance with the chemical formula H2O. A water molecule contains one oxygen and two hydrogen atoms connected by covalent bonds. Water is a liquid at ambient conditions, but it often co-exists on Earth with its solid state, ice, and gaseous state . Water also exists in a...

 in sports events (sports competitions or training) for some types of sports, such as various long distance types of running

Running

Running is a means of terrestrial locomotion allowing humans and other animals to move rapidly on foot. It is simply defined in athletics terms as a gait in which at regular points during the running cycle both feet are off the ground...

 (e.g., marathon

Marathon

The marathon is a long-distance running event with an official distance of 42.195 kilometres , that is usually run as a road race...

), cycling

Cycling

Cycling, also called bicycling or biking, is the use of bicycles for transport, recreation, or for sport. Persons engaged in cycling are cyclists or bicyclists...

, etc. Similarly, a water break is a break to drink water in some sports events held in one place.

Water stops and breaks have become obligatory relatively recently. Before the 1950s, there had been a practice to eliminate water breaks in order "to toughen up boys" (see "Junction Boys

Junction Boys

The Junction Boys is the name given to the “survivors” of Paul “Bear” Bryant’s 10 day summer football camp in Junction, Texas beginning September 1, 1954...

" for an example).

Water stops are used to combat interrelated dangers: hyperthermia

Hyperthermia

Hyperthermia is an elevated body temperature due to failed thermoregulation. Hyperthermia occurs when the body produces or absorbs more heat than it can dissipate...

, dehydration

Dehydration

In physiology and medicine, dehydration is defined as the excessive loss of body fluid. It is literally the removal of water from an object; however, in physiological terms, it entails a deficiency of fluid within an organism...

 and hyponatremia

Hyponatremia

Hyponatremia is an electrolyte disturbance in which the sodium concentration in the serum is lower than normal. In the vast majority of cases, hyponatremia occurs as a result of excess body water diluting the serum sodium and is not due to sodium deficiency. Sodium is the dominant extracellular...

. Drinking water combats dehydration, while intake of electrolyte

Electrolyte

In chemistry, an electrolyte is any substance containing free ions that make the substance electrically conductive. The most typical electrolyte is an ionic solution, but molten electrolytes and solid electrolytes are also possible....

 solutions (often provided by various sports drink

Sports drink

A sports drink beverage is designed to help athletes rehydrate when fluids are depleted after training or competition. Electrolyte replacement promotes proper rehydration, which is important in delaying the onset of fatigue during exercise...

s) combats hyponatremia and its extreme case: water intoxication

Water intoxication

Water intoxication, also known as water poisoning, is a potentially fatal disturbance in brain functions that results when the normal balance of electrolytes in the body is pushed outside of safe limits by over-consumption of water....

.

In a marathon, waters stops are usually at every 5K or at every 2 miles, resulting in 8-12 stops. Stopping for 10 seconds per station results in 1-2 minutes of added time, but the loss of stamina due to dehydration would add much more.

Compared to dehydration, hyponatremia is a relatively recently recognized danger, and there are different opinions about how much water to drink at each water stop. Some texts say that thirst

Thirst

Thirst is the craving for fluids, resulting in the basic instinct of animals to drink. It is an essential mechanism involved in fluid balance. It arises from a lack of fluids and/or an increase in the concentration of certain osmolites, such as salt...

 is not a reliable indicator of the need in water, while other say that obligatory drinking at every opportunity without real need increases the danger of hyponatremia. "If you hear sloshing in your stomach... you can by-pass that water stop". (Jeff Galloway

Jeff Galloway

Jeff Galloway is a former American Olympian and the author of Galloway's Book on Running....

)

In Sumo

Sumo

is a competitive full-contact sport where a wrestler attempts to force another wrestler out of a circular ring or to touch the ground with anything other than the soles of the feet. The sport originated in Japan, the only country where it is practiced professionally...

, if a bout goes for many minutes the referee may call a break traditionally called mizu-iri or "water break".