The effect of continuous strenuous exercise on intraocular pressure

Area of Science:

• Sports Medicine
• Ophthalmology
• Human Physiology

Background:

• Strenuous physical activity can impact physiological parameters.
• Understanding the effects of prolonged exercise on ocular health is crucial.

Purpose of the Study:

• To investigate the impact of a continuous 110-km march with a 20-kg backpack on intraocular pressure (IOP).
• To examine related physiological markers including plasma osmolarity, blood lactate, and pH.
• To determine correlations between IOP changes and other laboratory parameters.

Main Methods:

• A continuous 110-km march with a 20-kg backpack was performed by 22 healthy young volunteers.
• Intraocular pressure (IOP) was measured at various intervals during and after the march.
• Plasma osmolarity, blood lactate, pH, serum proteins, electrolytes, and hematologic parameters were analyzed.

Main Results:

• Intraocular pressure (IOP) significantly decreased during the march, with a maximal average reduction of 4.1 mmHg (26.5% below baseline).
• IOP returned to baseline 3 hours post-march but showed a secondary decrease 48 hours after, normalizing 48 hours later.
• Two peaks of increased plasma osmolarity were observed: one during the march and another 48 hours post-march.
• No significant correlation was found between IOP changes and blood lactate, pH, serum proteins, electrolytes, or hematologic parameters.

Conclusions:

• Continuous strenuous exercise, such as a 110-km march, leads to a significant reduction in intraocular pressure (IOP).
• The observed IOP reduction is inversely related to plasma osmolarity changes during and after prolonged, high-intensity exercise.
• These findings highlight a potential link between hydration status/osmotic balance and ocular pressure during extreme physical exertion.