Effects of exercise on intraocular pressure in physically fit subjects.

1. Several studies have shown that exercise reduces intraocular pressure (IOP) in sedentary subjects, but the effects of exercise in physically fit subjects are not fully known. Accordingly, the present study was planned to investigate the effects of exercise on intraocular pressure in physically fit subjects after elimination of those factors that can affect intraocular pressure and have been neglected by previous studies. 2. Thirty-two sedentary males of the same age group were categorized equally into control and experimental groups. Intraocular pressures were measured during and after exercise with the Goldmann applanation tonometer. The experimental group took a supervised exercise programme of 3 months duration. Physical fitness was evaluated by the measurements of maximum oxygen uptake. Each subject was tested twice by the same exercise protocol at an interval of 3 months. 3. After 3 months, resting IOP values decreased by 0.31 +/- 0.11 (P < 0.05) and 1.37 +/- 0.15 mmHg (P < 0.001) in control and experimental groups, respectively. The acute decreases following the first exercise test were 4.18 +/- 0.41 and 4.38 +/- 0.47 mmHg, while after 3 months these values were 4.12 +/- 0.45 and 2.69 +/- 0.28 mmHg in control and experimental groups, respectively. After exercise conditioning, the mean recovery time was reduced by 43.03%. 4. The results are relevant to planning trials in glaucoma. Physical fitness reduces IOP and causes significant attenuation in the IOP response to physical exercise. It would seem reasonable at present not to discourage patients who have glaucoma from light exercise; perhaps, on the contrary, it should be encouraged.