Study: IOP increases during weightlifting

Weightlifters experienced a higher IOP when they held their breath while lifting than when they breathed normally.

Issue: October 15, 2006

ByAndy Moskowitz

Weightlifters generally experience an increase in IOP while lifting weights, according to a new study. The increase is markedly higher if they hold their breath while lifting, according to a study published in the September issue of Archives of Ophthalmology.

Previous studies have shown that weight training leads to a post-exercise decrease in IOP from pre-exercise levels, but this is the first study to examine IOP changes that occur during lifting, the authors said.

Geraldo Magela Vieira, MD, of the Catholic University of Brasília, and colleagues measured the IOP of 60 eyes of 30 healthy males before, during, and after they lifted weights. The subjects, aged 18 to 40, performed 2 sets of 4 bench presses at 80% of their maximum lifting ability. IOP was measured during the final repetition as the subjects held the bar elevated.

For the first set, the subjects were told not to exhale during the final repetition and IOP was measured in the right eye. IOP increased in 27 subjects (90%), from a mean pre-exercise level of 18.6 mm Hg to 23.0 mm Hg during exertion. Nine subjects (30%) showed an increase of more than 5 mm Hg, according to the study.

For the second set, the subjects breathed normally throughout the exercise and IOP was recorded from the left eye. IOP increased in 18 subjects (62%), from a mean pre-exercise level of 18.8 to 21.0 mm Hg during exertion. Six subjects (21%) showed an increase of more than 5 mm Hg, according to the study.

The difference between the mean IOP change during the first set (4.3 ± 4.2 mm Hg) and the second set (2.2 mm Hg) was statistically significant (P = .02), the authors said.

Causes of increase

The authors suggest the IOP increase could be due to the Valsalva maneuver. The Valsalva maneuver causes an increase in intrathoracic venous pressure, which is transmitted through the jugular, orbital, and vortex veins to the choroid, bringing about an increase in IOP. A previous study that simulated the Valsalva maneuver showed an increase in IOP, the authors noted.

Similarly, the greater IOP increase observed when the subjects held their breath might be due to the retained air increasing intrathoracic pressure and thus IOP, according to the study.

The Valsalva explanation would also account for a small IOP decrease observed in some weight lifters, as a previous study suggested that decreased systemic arterial pressure could lower the intraocular blood volume and result in a net IOP decrease, the authors said.

Glaucoma risk

Previous studies have shown higher rates of normal-tension glaucoma in patients who experience transient increases in IOP caused by intrathoracic and intraabdominal pressure. The authors therefore caution that prolonged weight lifting “could be a potential risk factor for the development or progression of glaucoma.” Further weight lifting studies are under way to examine the IOP of older subjects, subjects with glaucoma, and subjects with many years of lifting experience, the authors said.

For more information:

Robert Ritch, MD, the corresponding author of this study, can be reached at Glaucoma Service, Department of Ophthalmology, New York Eye and Ear Infirmary, 310 E 14th St, New York, NY 10003; e-mail: ritchmd@earthlink.net.

Reference:

Vieira G, et al. Intraocular pressure variation during weight lifting. Archives of Ophthalmology. 2006;124:1251-1254.

Andy Moskowitz is an OSN Staff Writer who covers all aspects of Ophthalmology. He also writes daily for OSNSuperSite.com.