How Does a Horse Race Work?

Horse racing is one of the oldest of all sports and has evolved from a primitive contest of speed or stamina between two horses into an entertainment spectacle with large fields of runners, sophisticated electronic monitoring equipment, and immense sums of money. Critics argue that it’s inhumane and corrupted by doping and overbreeding, but supporters say the sport offers a glimpse of an elite world and that the winner of each race should be determined by who crosses the finish line first.

When a horse is declared the winner of a race, the stewards compare its time with that of the other horses to determine whether it finished ahead by a certain number of seconds or less. If no clear winner is determined, a dead heat is declared. A close call can result in a photo finish, where a photograph of the race’s conclusion is studied by a team of stewards to determine the winning horse.

The pace of a horse is an important factor in determining its chances of winning, and the pacing of a horse can be determined by watching its movements on the track and by analyzing the track conditions. Horses with a faster pace can win more races than those with a slower pace, although this is not always the case. A horse’s pacing can also be affected by the weather, as rain and colder temperatures slow the pace of a race.

Horses are trained to run so hard that they become dehydrated and lose fluid. To avoid this, all Thoroughbreds are injected with Lasix, a diuretic that is marked on the racing form with a boldface “L.” The drug’s main function is to prevent pulmonary bleeding from hard running, which can be dangerous for the horses and their jockeys. Its secondary effect is to cause the horses to unload epic amounts of urine—twenty or thirty pounds’ worth.

In handicap races, the weights that racehorses carry during a race are adjusted on the basis of the horse’s age and class (e.g., a two-year-old carries lighter weights than a three-year-old). There are also sex allowances for fillies and males.

Mary is a sports and hobbies researcher and writer for Britannica. She loves the thrill of the hunt for a great story and enjoys putting her research skills to work for our readers. She holds a liberal arts degree from Goddard College and spends her free time cooking, reading, hiking and exploring the natural world.

Get more race results, analysis and tips with a Premium subscription to Britannica.

Click or tap a race title to see more information about the race, including a full Timeform post-race analysis. A premium Timeform subscription will also give you access to Fast Results, giving you race results as soon as they happen. Detailed race card data is also available for all races. If you have a Timeform subscription, you can also make exotic wagers like a Pick 3 or 6 and create a Daily Double or Part Wheel.