By Dr. Cheryl G. Murphy, OD
Weightlifting can cause temporary but significant increases in eye pressure also known as intraocular pressure. In some cases, lifting heavy weights should be avoided by those who are at risk for or who have glaucoma but there are plenty of other aerobic exercises that can help one maintain a healthy eye pressure and lifestyle.
Most types of glaucoma involve increased intraocular pressure (IOP). Increased intraocular pressure can cause damage to the optic nerve particularly if it happens over an extended period and is significantly higher than the normal range. Controlling intraocular pressure and maintaining it at a lower level is one of the mainstays of treatment when managing most patients with glaucoma. Medications and special types of laser and surgical procedures can help to lower intraocular pressure, however, activities in our everyday life can cause spiking of our intraocular pressure and these spikes can happen to anyone, not just those with glaucoma.
Some spikes in eye pressure can be caused by Valsalva maneuvers. A Valsalva maneuver is defined as “the performance of forced expiration against a closed glottis. Many activities of our daily lives such as straining during defecation, playing the saxophone [and lifting heavy weights] entail the performance of the Valsalva maneuver.” One can think of a Valsalva maneuver as a moment when you strain, like when you push or pull something and because of your efforts your breathing is often held and then sharply exhaled like when you lift a heavy box, push something heavy like maybe your friend’s car which stalled or like when you lift weights either with your arms or push them with your legs. This straining causes changes to your blood pressure as well as other cardiovascular changes. It also, as mentioned earlier, can increase intraocular pressure.
A recent study conducted in New Zealand looked at weightlifting and its effect on eye pressure. The study had 24 participants do leg presses. The leg press is a popular piece of gym equipment that can help build the quadriceps and hamstring muscles as well as the glutes. This study used the 45-degree leg press that has a seat that reclines at an angle while your legs press upward in a diagonal direction. Before doing the leg press, while the participants were reclined, their IOP was measured, and they had an average IOP of 13.9 mmHg. Then their pressure was measured while they extended their legs and held up a heavy amount of weight while performing a leg press. It was also measured immediately after releasing the weight. An iCare tonometer was used to obtain the measurements at these three stages.
Researchers found that “there was a significant increase in IOP during weight-lifting exercises with the mean increase being 26.5 mm Hg (p<0.001) and a mean IOP across the group of 39.2 mm Hg.” The normal range for intraocular pressure is 9-21 mmHg. Anything above 21 or more importantly above 24 is considered significantly higher than average and most doctors warrant additional diagnostic testing and/or monitoring at that point. To see that lifting heavy weights, even with your legs, can cause the intraocular pressure to increase by 26 mmHg even temporarily is significant. It should be noted that intraocular pressure did return to normal baseline levels within a minute post exercise after they released the weight.
Other researchers such as Vera et al have also evaluated different aspects of the impact of weightlifting on IOP. “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. 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.” Therefore, the type of exercise performed and the number of repetitions you perform can also affect how high eye pressure rises.
Should glaucoma patients and those at risk for glaucoma avoid exercise? Absolutely not! In fact, exercising and maintaining good cardiovascular health is an essential part of keeping your eyes and body healthy and some types of exercise can even lower intraocular pressure. “Moderate aerobic exercise, such as jogging or bicycling, decreases intraocular pressure in un-medicated normotensive patients, as well as both normotensive and primary open-angle glaucoma patients on various anti-glaucoma drugs.” When choosing which type of exercise to do, lifting heavy weights may be one thing that patients should avoid but a brisk walk, jog or bike ride may be just what the doctor ordered to improve one’s eye and overall health.
photo credit: mathieu-chassara on Unsplash