Investigating the Immediate and Cumulative Effects of Isometric Squat Exercise for Different Weight Loads on Intraocular Pressure: A Pilot Study

Abstract

Background: The execution of resistance exercise against heavy loads promotes an acute intraocular pressure (IOP) rise, which has detrimental effects on ocular health. However, the effect of load on the IOP behavior during exercise remains unknown due to technical limitations. Hypotheses: IOP monitoring during isometric squat exercise permits assessment of IOP behavior during physical effort. Second, greater loads will induce a higher IOP rise.

Effects of caffeine consumption on intraocular pressure during low‐intensity endurance exercise: A placebo‐controlled, double‐blind, balanced crossover study

“…However, physiological responses to caffeine have demonstrated to be dependent on dose 38,39 and timing of ingestion 40 and, thus, the mediating role of caffeine‐dose and time frame between caffeine intake and IOP assessment during physical exercise deserves further investigation. Third, the type of physical exercise (ie, isometric and dynamic exercises), exercise intensity, participants' fitness level and level of dehydration are known to modulate the IOP response to exercise 31,41‐43 . It is our hope that future studies will assess the mediating role of these factors on the IOP response when caffeine is consumed before exercise.…”

Intraocular pressure fluctuation during resistance exercise

“…They have demonstrated that the execution of 1 min isometric squat exercise resulted in an IOP rise of approximately 8 mm Hg at the end of the 1 min effort, once the weight is released. 26 They have also observed that there is a progressive IOP increment with increasing repetitions with the magnitude of the increase in IOP being dependent on the type of exercise. 25 The investigators have also studied the IOP during 2 min of isometric exercises and observed an increase in IOP of 25% from baseline.…”

“…We hypothesise that IOP and blood pressure will be dramatically affected by nearmaximum effort weightlifting (leg press), 24 and the effect will be much more significant compared with what is measured previously. 25 26 We also hypothesise that such sharp change of IOP could be affecting the retina and choroid thicknesses. 27 The focus of this study is to characterise the time course of change measured before, during and after the leg press exercise.…”

The intraocular pressure response to lower‐body and upper‐body isometric exercises is affected by the breathing pattern

“…Endurance training at a low intensity (e.g., cycling or jogging) facilitates a reduction in IOP values [9,10], whereas resistance training (i.e., weightlifting) against heavy loads promotes an immediate IOP rise [11,12]. Importantly, the IOP response to resistance training is modulated by different factors such as the exercise modality (dynamic vs. isometric), exercise type (i.e., squat, bench press, biceps curl, military press), exercise intensity, or participants´ fitness level [12][13][14][15][16]. Specifically, greater changes in IOP values have been observed during isometric compared to dynamic exercises, while increases in IOP values have been positively associated with the size of the muscle mass involved in the exercise and the load used [12, 14,16].…”

“…Importantly, the IOP response to resistance training is modulated by different factors such as the exercise modality (dynamic vs. isometric), exercise type (i.e., squat, bench press, biceps curl, military press), exercise intensity, or participants´ fitness level [12][13][14][15][16]. Specifically, greater changes in IOP values have been observed during isometric compared to dynamic exercises, while increases in IOP values have been positively associated with the size of the muscle mass involved in the exercise and the load used [12, 14,16]. In addition, high-fit individuals have shown a more stable IOP response to exercise than lowfit individuals [13].…”