The safety of exercises like planks is a common concern for individuals managing glaucoma. Glaucoma is a progressive eye disease characterized by damage to the optic nerve, which transmits visual information from the eye to the brain. This damage typically leads to irreversible vision loss, starting with peripheral vision. The primary risk factor associated with this damage is often elevated pressure inside the eye (IOP). Evaluating exercises like the plank requires understanding how specific physical movements can temporarily affect the eye’s internal environment.
Understanding Glaucoma and Intraocular Pressure
Glaucoma involves the deterioration of optic nerve fibers, primarily driven by high intraocular pressure (IOP). The eye produces a fluid called aqueous humor, which fills the front part of the eye and normally drains out through the trabecular meshwork. Glaucoma develops when this drainage system becomes blocked or restricted, causing the aqueous humor to accumulate.
This fluid buildup increases the IOP, which then presses on the optic nerve, causing damage over time. Maintaining a stable, lower IOP is the goal of most glaucoma treatments to slow or halt vision loss. Any activity that causes a temporary spike in this pressure is a concern, as even brief fluctuations can be damaging to an already compromised optic nerve.
Analyzing the Risk of Isometric Core Exercises
Planks are a type of isometric exercise, which involves holding a position without moving the joint, generating significant muscle tension in the core, arms, and legs. Scientific evidence suggests that isometric exercises can cause an acute, temporary rise in IOP. This pressure increase is often linked to the body’s physiological response to straining, particularly the Valsalva maneuver.
The Valsalva maneuver occurs when a person holds their breath and forcefully attempts to exhale against a closed airway. This is common during intense static holds or heavy lifting. This action temporarily spikes systemic blood pressure and increases pressure in the chest and abdomen, which is then transmitted to the head and eyes. For some individuals, this straining can cause a rise in IOP, with some studies recording increases of up to 20 millimeters of mercury (mm Hg) above baseline.
The risk associated with planks is not the exercise itself but the breathing technique used during the hold. If a person holds their breath or strains excessively, they are risking a significant IOP spike. Furthermore, any position that places the head below the heart, which can happen with poor plank form or during inverted poses like a downward dog, also increases pressure on the eyes. Studies show that for healthy individuals, this pressure quickly returns to normal, but the effect on an eye already weakened by glaucoma is a point of caution.
Safe Exercise Modifications and Alternatives
For individuals with glaucoma who wish to maintain core strength, the safest approach involves careful modification and the selection of lower-risk alternatives. The single most important adjustment when performing any strenuous exercise, including a plank, is to avoid the Valsalva maneuver entirely. This means focusing intensely on continuous, controlled breathing, exhaling during the most difficult parts of an exercise and never holding the breath.
If a plank is attempted, the duration of the hold should be kept short, and the neck should remain neutral, avoiding any position where the head drops below the level of the heart. For a more controlled approach to core work, alternatives like the bird-dog exercise or pelvic tilts can effectively target the core without the same risk of straining.
Low-impact aerobic activities such as walking, cycling, or swimming are generally recommended, as they have been shown to have a transient IOP-lowering effect. When performing any strength training, a focus on lighter weights with a higher number of repetitions is safer than heavy lifting. Ultimately, before adopting a new or high-intensity exercise routine, consultation with an ophthalmologist is highly recommended. This consultation ensures that any exercise plan supports overall fitness while protecting vision.