Endurance, or stamina, is the capability of sustaining prolonged stressful effort.

Endurance exercise

Endurance exercise consists of performing low- to medium-intensity exercise for very long periods of time. E.g., jogging or running several miles to hundreds of miles; cycling dozens of miles to thousands of miles; swimming hundreds of yards to dozens of miles.

Physical endurance is differentiated from other forms of physical stress in that in endurance exercise fatigue of the muscles and cardiovascular system do not force the effort to end. The need for sleep, the buildup of non-recyclable waste chemicals, the depletion of convertible energy stores and other needed chemicals (e.g., water, sodium), physical injury, psychological failure, or attainment of the goal will bring the effort to an end.

Equestrian Sport

In equestrian sport, "endurance" refers to long distance races (often 100 miles) ridden by one horse-rider pair. The course is set, and the athletes all start at the same time. Endurance races were part of military history and also have a place in the history of the American West. The Tevis Cup is a famous race from the east to the west side of the Sierra Nevada.

It is an international sport and is governed at the international level by the Federation Equestre Internationale (FEI).

Auto Racing

In Auto Racing, "endurance" refers to long distance races often 1000 Kilometers of more. Usually a car is being shared by 3 to 5 drivers in these 8 hour plus events. The 24 Hours of Le Mans is the most famous endurance race in the world. The 24 Hours of Daytona and the 12 Hours of Sebring are the most famous endurance races in North America. There is also the Spa 24 Hours at Spa-Francorchamps and Zolder 24 Hours in Belgium as well as the 25 Hours of Thunderhill in California and Takashi 24 in Japan. But the most gruelling endurance race in the world is the 24 Hours of Nurburgring in June, where some 200 cars start the race under the most unpredictable weather conditions around the 23 kilometer track in the Eifel Mountains of Germany.

Aviation

In aviation, the "endurance" of an aircraft refers to the maximum amount of time it may remain in flight with a given amount of fuel.

Non-athletic endurance

Any act requiring sustained patience or tolerance of stress is endurance. Examples include: sitting in an airport for 2-weeks; sitting on a flag-pole for several months; surviving as a prisoner-of-war for several years.