Recent studies have shown there is an increase in intraocular pressure (IOP) for weightlifters while exercising, particularly when performing isometric activities or very heavy lifts. Increased pressure in the eye is also the main cause for Glaucoma, a condition of the eye that may lead to partial or full vision loss.
Glaucoma is an eye disease that affects roughly two million people in the US. A progressive increase in intraocular pressure is a major cause of the condition. This pressure is a result of a build up of fluid (and poor drainage of it) within the eyeball that can lead to damage of the optic nerve (the nerve that transfers information from the eye to the brain). Though distinct symptoms are rare, loss of peripheral vision, headaches with nausea and vomiting, pain behind the eye ball and halos around lights can occur.
Funded by the New York Glaucoma Research Institute, a research paper was published in February 2006 on “Intraocular Pressure Variation During Weight Lifting” by Brazilian researchers. Measuring the IOP of the test subjects while executing bench presses, the study could successfully establish an increase in pressure inside the eye.
In 2008, a Norwegian study was presented on the same topic, further backing the conclusion, proving a significant intraocular pressure increase continuously during isometric exercise.
Increased IOP when weightlifting is a direct result of the technique used by many weightlifters of holding one’s breath, most commonly in the latter stages of a set, when a stressful exercise is undertaken. There is an inclination to do this because it tends to give the body balance, stability and more focus on a certain muscle movement. The study in Brazil showed that those who breathed consistently through the set had a significantly lower increase in IOP compared to those who restricted their breathing. Besides obvious limitations in oxygen flow to muscle cells, by holding your breath while lifting heavy objects, it also almost doubles the increased pressure within the eye.
Despite the undeniable occurrence of increased IOP in isometric exercises and heavy weight lifting, no direct conclusion has been made regarding weight lifting as a cause of Glaucoma, as the condition develops over longer periods of time, but the studies can point to an increased risk in developing the disease.
Those that lift weights frequently, or those that are in a profession where heavy lifting is common, are recommended to visit your local eye doctor for further advice. Conclusively, a suggested tip to help reduce the risk of Glaucoma is a rich diet including Omega 3 fatty acids, found in fish, cabbage, walnuts and broccoli. Studies have proven a 13 % reduction in IOP in subjects on a high Omega 3 diet.