Effects of submaximal exercise with water ingestion on intraocular pressure in healthy human males

The effects of exercise and water replacement on intraocular pressure (TOP) have not been well established. Furthermore, it is not known whether the temperature of the fluid ingested influences the TOP response. In the present study we determined the effect of water ingestion at three temperatures (10, 24 and 38degreesC; 600 ml 15 min before and 240 ml 15, 30 and 45 min after the beginning of each experimental session) on the TOP of six healthy male volunteers (age = 24.0 +/- 3.5 years, weight = 67.0 +/- 4.8 kg, peak oxygen uptake (VO2peak) = 47.8 +/- 9.1 ml kg(-1) min(-1)). The subjects exercised until exhaustion on a cycle ergometer at a 60% VO2peak in a thermoneutral environment. TOP was measured before and after exercise and during recovery (15, 30 and 45 min) using the applanation tonometry method. Skin and rectal temperatures, heart rate and oxygen uptake were measured continuously. TOP was similar for the right eye and the left eye and increased post-water ingestion under both exercising and resting conditions (P<0.05) but did not differ between resting and exercising situations, or between the three water temperatures. Time to exhaustion was not affected by the different water temperatures. Rectal temperature, hydration status, heart rate, oxygen uptake, carbon dioxide extraction and lactate concentration were increased by exercise but were not affected by water temperature. We conclude that TOP was not affected by exercise and that water ingestion increased TOP as expected, regardless of water temperature.