Sixty-one studies were included. The number of participants is reported below, where possible.
Physical fitness (24 studies).
Exercise intensity (17 studies, n=327): during tennis play, the mean heart rate ranged from 141 to 182 beats per minute, mean oxygen consumption ranged from 23.1 to 40.3 mL/kg per minute, and the mean lactate level was generally 2 to 3 mmol/L.
Aerobic capacity (1 longitudinal study and 15 cross-sectional studies, n=260): the mean maximum oxygen consumption of tennis players ranged from 35.5 to 65.9 mL/kg per minute. The longitudinal randomised controlled trial reported that tennis was associated with modest increases in endurance capacity compared with cycling and jogging.
Cardiovascular risk factors.
Obesity (4 cross-sectional studies, n>7326): 3 studies reported that tennis players had a lower percentage of body fat than controls (average values or age matched active group). One study reported that runners/joggers/fast walkers and tennis players were less likely to be obese than participants in team or other sports.
Hyperlipidaemia (2 cross-sectional studies and 1 longitudinal study, n>118): mean plasma high-density lipoprotein levels were significantly higher in tennis players compared with sedentary people, while very low-density lipoprotein and triglycerides were significantly lower (1 study). There was no significant difference in high-density lipoprotein cholesterol, low-density lipoprotein or triglycerides for a tennis training group compared with tennis as usual group (1 study), or between elite senior tennis players and an age-matched active control group (1 study).
Hypertension (2 cross-sectional studies, n=67): one study reported that systolic-blood pressure rose during play from a resting value of 137 to 168 mmHg, while diastolic blood-pressure decreased from 88 to 82 mmHg. One study reported no significant difference in systolic or diastolic blood-pressure between senior elite tennis players and an age-matched active group.
Diabetes mellitus (1 longitudinal study, n=12): this study reported no significant change in baseline glucose levels, glycated haemoglobin levels or free fatty acids after tennis training in people with type II diabetes. There were small but statistically significant increases in plasma insulin and C-peptide levels.
Cardiovascular morbidity and mortality (1 longitudinal study): this study reported that people who reported high or low tennis ability at medical school were at significantly lower risk of cardiovascular disease after 22 to 40 years than people with no ability (adjusted analysis).
Heart size (8 studies, number of participants not reported): elite tennis players were found to have increased heart size and performance capacity, but systolic and diastolic function within normal limits.
Osteoporosis (20 cross-sectional studies and 2 longitudinal studies, n=2,045): overall, bone mineral concentration and bone mineral density were found to be consistently greater in the playing arm than the non-playing arm. Hip and lumbar spine bone mineral concentration and density were greater in tennis players than in controls.