Pumping up the Pressure

Those who regularly “pump iron” down the gym will be familiar with the physical feelings that come with intense resistance exercise. But what impact may strength exercises have on the body, and IOP in particular? A team from the University of Granada, Spain, found that IOP significantly increased when resistance training exercises were performed (1).

Jesús Vera, lead author of the study, explains what led them to design the project: “We have a really active collaboration with the Faculty of Sport Sciences at the University of Granada, and we have each shown the importance of considering physiological changes induced by anaerobic exercise. This led us to consider changes in IOP.” Enrolling 17 male military officers from the Spanish Army, the team got them to perform jump squats and bench presses with progressively heavier loads, and measured IOP before and after each load using a rebound tonometer. IOP increase was found to be linearly associated with increasing load, and the bench press was found to induce a greater increase than jump squats at the same relative load. Though they were expecting to see an increase in IOP, Vera says that they “did not expect the almost perfect linear association between the magnitude of resistance and the change in IOP.” The team also found that five minutes of rest was sufficient time for IOP to return to baseline values.

So what impact do the findings mean for glaucoma management? Vera urges caution: “Recent studies have shown that exercise is beneficial in the management of glaucoma, but our findings were obtained with healthy participants, and therefore the effect on patients with glaucoma still needs to be studied. We also want to highlight that the type and intensity of exercise is of vital importance depending on the main goal of this exercise prescription.” The team are now focusing on how fitness level impacts IOP increase during different exercise protocols, as well as testing the long-term effects of different physical training programs on baseline IOP levels and IOP responses to exercise. For now, Vera offers some advice: “From this study, and some others that we have recently conducted, we can state that exercise is highly beneficial, but that progressive involvement is desirable; individuals in poorer physical condition manifest higher IOP peaks with exercise and should avoid highly demanding physical activities.”