Horse races are a popular sport that attracts millions of spectators. They are also the subject of intense debate, from questions about whether horses suffer to allegations of corruption and exploitation. Following the deaths of dozens of horses at Santa Anita Park in 2019, a number of reforms have been implemented, but many critics argue that the industry is not yet safe.

Horses race in a variety of different ways, from flat races to steeplechases. The types of races are determined by the rules that govern them, which vary by country and state. Flat races are run over dirt, and steeplechases take place on grass or sand. Both races require a great deal of physical endurance, and many horses die while competing. The most common causes of death are heart attacks and injuries, which often occur during the stretch run.

Historically, Thoroughbred racing was more about stamina than speed. After the Civil War, however, a new emphasis was placed on speed, and American horse breeders developed faster horses. Winning time in a race is a complex combination of the horse’s innate desire to run and a host of human inputs. In particular, the jockey’s position in the starting gate, the ‘going’ of the track and tactics all play a role. In addition, for pacers (a type of racehorse that uses the pacing gait, where its front and back legs move in unison), there is a strong psychological incentive to win and set record-breaking times.

For all these reasons, winning time in a race may not be the best measure of a horse’s performance. In fact, linear regression analysis shows that in both man and the horse, the improvement in winning times has slowed since 1949. This may be due to the fact that most of the improvements in these races occurred prior to that date, or it could be a result of more esoteric factors, such as improved nutrition and, for the racehorse, selective breeding.

A number of races have been designated as “graded” by the governing body, with the top grade being Grade 1 (G1). These races feature higher purses, and may be restricted to a specific age group or to horses sired by participating stallions. Additionally, some races are handicapped, with a racing secretary or track handicapper assigning weights to allow each horse to compete on an equal basis.

Generally, the more weight a horse carries, the better its chances are of winning. In addition to the overall weight carried, race horses are assigned additional penalties or allowances based on their past performances. For example, a two-year-old filly will carry more weight than a three-year-old male horse, and horses that have won are awarded weight penalties.