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, according to a study published in the August issue of BioMed Central Ophthalmology.

The authors assigned 145 participants (100 normotensive and 45 POAG patients) to one of seven groups:
• Un-medicated normotensives (25 subjects).
• Normotensives treated with timolol maleate 0.5% (40 subjects).
• Normotensives treated with latanoprost 0.005% (20 subjects).
• Normotensives treated with brimonidine tartrate 0.2% (15 subjects).
• POAG patients on timolol maleate monotherapy (15 subjects).
• POAG patients on latanoprost monotherapy (15 subjects).
• POAG patients on various combinations of timolol maleate, latanoprost and brimonidine tartrate (15 subjects).

At the study’s conclusion, the authors found that subjects from all seven groups demonstrated statistically significant reductions in IOP during jogging. Most importantly, however, the authors concluded that all glaucoma patients should participate in regular, moderate exercise.

“This study underscores what we have suspected for a long time––that aerobic exercise transiently decreases IOP,” says Joseph W. Sowka, O.D., professor at Nova Southeastern University College of Optometry. “I suspect that dehydration from sweating is involved, but ultimately, the reason is unknown.”

Dr. Sowka, however, remains unconvinced that regular aerobic exercise alone would eliminate the risk for ocular hypertension. “The authors have shown that IOP decreases for about half an hour [after jogging], but nothing beyond the pre- and immediate post-levels of IOP. Such an ephemeral IOP reduction likely doesn’t have an impact on the clinical course of the disease,” he says.

Also, “There could be an inherent danger here if these glaucoma-exercise advocates think that exercise will control their IOP,” Dr. Sowka says. Patients should not try to substitute jogging for glaucoma medicines, he adds.

“That all being said, I believe that we should advocate exercise of some sort as well as healthy eating to patients with glaucoma—it enhances the vascular system and that may enhance optic nerve perfusion,” says Dr. Sowka. “Further, if exercise can control blood pressure and a hypertensive patient can avoid medications, then he or she could possibly avoid medication-induced hypoperfusion, which significantly decreases ocular blood flow, possibly worsening glaucoma.”

Natsis K, Asouhidou I, Nousios G, et al. Aerobic exercise and intraocular pressure in normotensive and glaucoma patients. BMC Ophthalmol. 2009 Aug 13;9:6.