As with any exercise, the number of calories you burn playing tennis depends on how intensely you are working. Tennis can be a leisurely activity played by doubles partners for a half an hour or it can be a grueling battle between two highly competitive people that can go on for hours.
Tennis is played on a hard court, grass or clay. Although there is a way to play with three people, the most common games are singles and doubles. Matches are typically played as best two out of three sets or best three out of five sets. A set is won by a player who wins six games--though he must win by at least two games (six games to four, for example). Otherwise, sets can include a single tiebreaker game or can continue until one player wins by two games.
A 5-foot-5, 30-year-old woman who weighs 130 pounds will burn 404 calories in an hour of competitive singles tennis. A 50-year-old woman of the same height and weight will burn about 30 fewer calories in an hour.
A 6-foot, 30-year-old man who weighs 160 pounds will burn 511 calories in an hour of competitive singles tennis. A 50-year-old man of the same height and weight will burn 472 calories.
The 30-year-old woman playing competitive doubles tennis will burn 289 calories in an hour. The 50-year-old woman will burn 20 fewer calories.
The 30-year-old man playing competitive doubles for an hour will burn 365 calories. The 50-year-old man will burn 337 calories.
The number of calories burned playing tennis varies considerably depending on the level of competition. The numbers listed are examples for active games in which the players are on the move most of the time. Competitive tennis burns about twice as many calories than competitive indoor volleyball, about the same as basketball and about two-thirds as much as cross-country skiing.