It’s no secret that frequent exercise is a prominent key in the journey for holistic wellness. In referencing most publications, one will find that sedentary lifestyles tend to increase the risk of systemic co-morbidities and consequently decrease total health. The eyes are no different.
This article will peel back the curtain on today’s literature regarding the predominantly positive, though some negative, impacts of exercise on the eyes.
The many benefits of exercise
It’s no foreign concept that exercise is a healthy habit. From marketing campaigns for gym memberships to Instagram influencers, this is a world inundated with exercise awareness. The medical community too has grown fond of exercise as a means to combat the overweight and obesity epidemic.
Engaging in physical activity serves multiple purposes:1
- Maintain a healthy weight
- Increase cardiovascular health and improve circulation
- Improve mental health
- Reduce the risk of metabolic syndrome
The Centers for Disease Control and Prevention (CDC) recommends a total of 150 minutes of exercise per week or the equivalent of 30 minutes per day. These regimens should incorporate moderate intensity workouts with 2 days of strength training.2
It’s best practice to advise close oversight with a patient’s primary care physician. Additionally, as many patients have specific fitness requirements, it’s recommended to develop a referral network including dietitians, nutritionists, physical therapists, as well as local fitness professionals.
As clinicians, it’s important to assist our patients in understanding a holistic approach to treatment with the inclusion of healthy lifestyle changes. Physical fitness, in particular, has an intriguing effect on ocular health.
The effects of exercise on the eyes
A holistic health plan, with the addition of physical fitness, is capable of both preventing and slowing conditions that may otherwise cause blindness, vision loss, or reduced comfort. Let’s explore a subset of common ocular diagnoses and how they are impacted by routine exercise.
Danger of developing diabetic retinopathy
Best to begin with the association between exercise and diabetic retinopathy. A sedentary lifestyle is directly correlated to the onset of nearly 27% of patients diagnosed with diabetes.8
Additionally, a lack of physical activity is linked to significant progression of diabetes and negative sequelae such as diabetic retinopathy, nephropathy, and kidney disease. It is believed that increased physical fitness actively negates the degradation of one’s diabetic status by combating microvascular disease. Albeit, the complete mechanism is still unknown, and further research is required.
One such hypothesis is the concept of preconditioning. The theory involves interleukin-6 (IL-6), a myokine with both pro- and anti-inflammatory mechanisms. During exercise, muscle tissue releases IL-6 in an anti-inflammatory role. Concurrently, patients displaying diabetic retinopathy tend to have an increased presence of pro-inflammatory interleukin-6 in both aqueous and vitreous.
The evolving hypothesis presumes that exercise potentially preconditions the retina to IL-6 and curtails the effects of low-grade, chronic inflammation commonly exhibited with diabetic retinopathy.3
A separate study investigated the effects of exercise on systemic inflammation. The results revealed the capability of aerobic exercise to reduce overall inflammation, oxidative stress, and protect against more severe diabetic complications.4
Does a sedentary lifestyle increase the risk of AMD?
Let’s move on to age-related macular degeneration (AMD). Ask your average eye doctor and you’ll find that typical recommendations include an increased intake of leafy green vegetables, an AREDS2 formula multivitamin, and a pair of sunglasses. Although, how often is exercise mentioned as a part of the plan?
A meta-analysis conducted in 2017 attempted to answer this question. The researcher analyzed nine separate studies with a goal of understanding the association between physical activity and its propensity to delay the onset, as well as progression, of macular degeneration in a white population.
The study concluded that not only did physical activity lower the odds of early macular degeneration, but also reduced the risk of progression toward later stages of the disease.5 To further the discussion on macular degeneration, a cross-sectional study was performed to determine the effect of macular degeneration on physical activity.
The findings revealed a hypothesized, bidirectional relationship in which a greater severity of macular degeneration decreased the likelihood of a physically active lifestyle, and a sedentary lifestyle increased the likelihood of greater disease severity.
It’s proposed that a sedentary lifestyle promotes inflammatory retinal conditions with resultant dysfunction of the endothelial tissue. Patients exhibiting more advanced macular degeneration were also less likely to engage in physical activity due to visual impairment.6
The relationship between glaucoma and exercise
Glaucoma and exercise may best be characterized as a love-hate relationship. While studies have proven a decrease in intraocular pressure associated with aerobic exercise and strength training, yoga can have the opposite effect. In fact, certain yoga positions may even add 10mmHg of increased pressure for the duration of the pose.7
When discussing glaucoma and exercise with patients, consider recommending 30 to 45 minutes of aerobic exercise for five sessions per week for overall metabolic health. If discussing strength training, consider recommending caution with overexertion and holding one’s breath.
This is especially true for exercises that may result in inversion or Valsalva maneuver—such as headstands in yoga or bench pressing heavy weights.8
When working out brings you to tears
Similar to macular degeneration, most common regimens for dry eye management will not mention exercise. However, a recent literature review of the effects of exercise on the tear film may change that tune. The review found that the composition, quantity, and quality of the tear film improved with a singular event involving aerobic exercise.9,10
Moreover, chronic aerobic gym goers reported an overall improvement in dry eye symptoms. It was determined that not only was there an increase in tear volume, but also an increase in tear breakup time. Although osmolarity increased, it remained within an acceptable range.
Perhaps most importantly, cytokine markers for inflammation decreased within the tear makeup, therefore reducing common irritation associated with dry eye disease.15 The research is continuously ongoing. For now, consider recommending some cardio for those chronic dry eye patients.
Recognizing the limits of physical fitness
It’s undoubtable, we live in a world where successful marketing has nearly raised fitness to the level of divinity. While there is truth that physical fitness has a net positive effect when accounting for chronic eye disease, prior to recommending exercise for all of your patients, it’s important to consider some of the negative outcomes that exist as well.
A rule of thumb is aerobic exercise tends to be safe, whereas anaerobic (e.g., quick, short bursts, such as heavy weightlifting) should be approached with a hair of caution.
Outlined below is a list of cautionary findings associated with exercise and visual or ocular manifestations:
- Valsalva retinopathy may occur from increased pressure within the chest cavity that results in damage or rupture of fragile retinal blood vessels.
- This is a rarer form of retinopathy that can result in a macular, preretinal hemorrhage with associated vision loss.11 Exercises that increase risk would include heavy weight training and intense aerobic exercise.
- The Uhthoff phenomenon is a transient, worsening of vision while exercising in the heat. It is commonly associated with conditions that transpire into optic neuritis, such as multiple sclerosis or sarcoidosis.12,13
- As noted previously, practice caution regarding heavy lifting, as well as yoga, when recommending physical activity for patients with glaucoma.8
A warning about combat sports
Gaining more popularity in the fitness world is an array of combat sports. Ranging from mixed martial arts to boxing, these activities are an excellent source of cardiovascular exercise. However, for patients engaged in active combat, such as sparring, it’s important to have an understanding of the acute and chronic sequelae.
Every eyecare professional is taught the story of the boxer with angle recession glaucoma. The pathophysiology includes ocular trauma that results in damage to the trabecular meshwork, thus impeding appropriate aqueous flow.
Repeated trauma may be associated with angle recession glaucoma and should be monitored appropriately with gonioscopy and intraocular pressure checks. It is suggested to monitor patients for clues such as iridodialysis, iris atrophy, or scarring in the surrounding adnexal regions.
What to look for in patients with angle recession glaucoma
Trauma is associated with a slew of acute findings including hyphema, corneal abrasions, LASIK flap displacement, subconjunctival hemorrhages, iridodialysis and adnexal ecchymosis. Take note that the infraorbital groove is the weakest structure of the orbit, located within the floor, and is thus increasingly susceptible to fracture with trauma.
Orbital blowout fractures, involving this particular region, may result in a trapping of the inferior rectus. Such entrapment typically results in diplopia, caused by restriction of the ipsilateral eye in upgaze. Damage to the trochlear nerve or abducens may occur as well, highlighting the importance of finely assessing extraocular motility.
Retinal findings are also common. It’s crucial to monitor for retinal tears, detachments, and commotio retinae. Advise particular caution to high myopes or patients with a history of retinal pathology (ex., lattice degeneration, etc) when partaking in these activities.
Final thoughts
There’s no doubt that the word exercise has found its way to the top of America’s “Buzz Words” chart. As eyecare professionals, it’s imperative to stay both in the “know” about the latest research and to encourage healthy lifestyles.
So, remember these takeaways:
- Aerobic exercise is most beneficial at increments of roughly 150 minutes per week. Pending a patient’s physical capabilities, consider recommending sessions of 30 to 45 minutes at 5 days per week.
- Anaerobic exercise (ex., weightlifting, etc.) is beneficial with certain considerations regarding exertion for at-risk patients,
- Speciality exercises such as yoga or combat sports come with specific risks.
All in all, a holistic prescription of a healthy lifestyle, alongside a good eye exam and refraction, will make for healthier, happier patients who will see the difference. Now get moving and encourage your patients to do the same!
