The Benefits of Exercise
Chat Highlights
August 31, 2005

On Wednesday, August 31, 2005, Dr. Rick Wilson a glaucoma specialist at Wills, and the glaucoma chat group discussed "The Benefits of Exercise."

Moderator:  Welcome, Dr. Wilson.  Our topic tonight concerns the benefits of exercise for glaucoma patients.  Does the type of exercise make a difference?

Dr. Rick Wilson:  Three months of aerobic training lowers IOP (intraocular pressure) about 4 mm Hg.  Vigorous exercise lowers it transiently another 3 to 4 mm Hg on the basis of dehydration, increased CO2, and so on.

P:  How is C02 connected with lower IOP?

Dr. Rick Wilson:  CO2 dilates vessels and lowers venous pressure.  Therefore, the resistance to aqueous exiting the eye into the blood vessels is lowered.

P:  What type of exercise do you think is the best for lowering IOP?

Dr. Rick Wilson:  The best exercise is any aerobic exercise that raises your heart rate for 20 minutes or more at a time.  Running, walking, exercise biking, or swimming top the list.

P:  Will exercise that lowers the IOP 4 mm Hg sustain that lower pressure over time?

Dr. Rick Wilson:  From the studies I've seen, it seems the IOP decrease continues as long as the exercise is maintained.  Clearly, NordicTrack, the Elliptical Trainer, and the StairMaster would help patients meet their goals.

Moderator:  Is walking enough exercise or does the exercise have to be something more strenuous?

Dr. Rick Wilson:  Most studies show that even moderate exercise has a beneficial effect.  You need to get your heart rate up and hold it there for 20 minutes, 4 times a week, to achieve the decrease in pressure.

P:  If you have NTG (normal-tension glaucoma), what is the benefit of lowering your pressure through exercise?

Dr. Rick Wilson:  What we found out from the NTG study is that IOP is important, and the lower the IOP, the less chance there is of progression.  Clearly, exercise has other benefits that are very important in NTG, such as improving circulation and general health (i.e., lowering blood pressure and blood sugar).

P:  I thought low blood pressure was bad for glaucoma patients, because not enough blood is pumped to the eye.  Or are you talking about NTG patients only?

Dr. Rick Wilson:  Blood pressures that is too low does decrease perfusion pressure -- the pressure pushing blood through the vessels to the optic nerve.  However, if a glaucoma patient has blood pressure that is slightly high or too high, lowering it through increased conditioning prevents the changes that happen to the vessels with hypertension over time, which is beneficial for glaucoma patients.

P:  What do you think about the benefits of yoga for glaucoma patients?

Dr. Rick Wilson:  Yoga has many benefits, such as relaxation, toning and flexibility, but aerobic conditioning is not one of them.

P:  Do you have any patients who believe that practicing yoga has decreased their IOPs?  I believe that my IOPs and blood pressure have benefited from my yoga practice.  I have no proof, but it's awfully coincidental.

Dr. Rick Wilson:  The general relaxation and lower blood pressure achieved with yoga have been cited by my patients as lowering their IOP.  I also have no proof.

P:  But I thought we weren't supposed to do yoga.

Dr. Rick Wilson:  No.  Yoga is fine, except for positions that involve head down and body up for any extended periods.  For example, yoga headstands are out.

P:  Would it be okay to do a yoga pose with the head below the heart for five minutes not but for thirty?

Dr. Rick Wilson:  If the head is not much lower than the heart, I, personally, feel a minute might be reasonable.  If the head is much lower, then 15 to 30 seconds would be safer if you have serious glaucoma.

P:  What about exercise that lowers the head below the heart, like hanging from those boots people use?  Why isn't it good for glaucoma patients to have the head lower than the heart?

Dr. Rick Wilson:  That's the same situation, with all the blood pooling in the head and raising the venous pressure in the veins into which the aqueous drains.  With a higher pressure in those veins, the aqueous can't drain from the eye and the IOP increases.

P:  Would weight training, such as bodybuilding, be of any benefit?

Dr. Rick Wilson:  It would be of some benefit for general health and bone density, but not much for lowering IOP.  In fact, lying on your back and doing leg presses with heavy weights would raise your IOP during the time of the exercise.

P:  Besides the health benefits, does exercise positively affect glaucoma patients whose IOP is controlled with filtering surgery?

Dr. Rick Wilson:  We don't know enough to say exactly, but excellent health and cardiovascular conditioning seem to retard progression of glaucoma.  If your pressure is low from the filtering surgery, that effect may not be as apparent.

P:  Does swinging the arms while walking increase the benefits of walking?

Dr. Rick Wilson:  Yes.  Some recommend holding light weights in the hands, but I don't know how much extra stress that puts on the joints.

P:  I thought low blood pressure was bad for glaucoma patients, because not enough is blood pumped to the eye.  Or are you talking about NTG patients only?

Dr. Rick Wilson:  Blood pressures that is too low does decrease perfusion pressure, the pressure pushing blood through the vessels to the optic nerve.  However, if a glaucoma patient has blood pressure that is slightly high or too high, lowering it through increased conditioning prevents the changes that happen to the vessels with hypertension over time, which is beneficial for glaucoma patients.

P:  Is there a minimum number of heart beats per minute (bpm)for achieving good blood circulation and oxygenation?

Dr. Rick Wilson:  As I remember, the training heart rate is optimal at about (I forget the exact number, so don't quote me) is 180 to 190 bpm, minus your age.  Clearly, if you are older or have any health problems, any exercise program should be cleared by your internist first.  [Editor's note: You can find a training heart rate calculator at http://www.healthchecksystems.com/heart.asp.]

P:  I have read that Tai Chi is of some benefit in lowering IOP.

Dr. Rick Wilson:  I think it is in the same category as yoga for lowering IOP.

P:  Since exercise is so beneficial, do you agree that patients with pigmentary glaucoma should avoid exercise involving much movement?  Once the trabecular meshwork gets to be so compromised, say, with four-plus angle pigment, does it make sense to try to prevent further pigment release by avoiding certain types of exercise?  Might it not be beneficial to trade off the extra pigment for the benefits of exercise?

Dr. Rick Wilson:  The exercise that adversely affects pigmentary glaucoma is impact exercise like basketball.  An exercise bike or swimming can achieve the benefits of exercise without the added pigmentary dispersion seen with impact exercise.

P:  When I ride my bike, I usually wear sunglasses, but I can still feel the air rush against my eye.  I have ICE (irido-corneal) syndrome.  After a few minutes, my eye feels hot.  Is that affecting the pressure, or just irritating my eye that is probably irritated by all the drops I'm using?

Dr. Rick Wilson:  I think the air is just drying out the surface of the eye already irritated by the topical medications you use.  The air will have no effect on your IOP.

P:  Should glaucoma patients who swim in pools be concerned about the chlorine?

Dr. Rick Wilson:  Unless there is a bleb, the chlorine should be of no more concern than for normal eyes.

P:  If we exercise, can we skip using glaucoma eye drops on the days we exercise?

Dr. Rick Wilson:  It is best to exercise for six weeks to make sure you have achieved the beneficial effect, then ask your doctor if you could try a reverse, one-eyed therapeutic trial.  That is, stop using the eyedrop that your doctor suggests in one eye, and then get your IOP checked several weeks later to see if is still controlled in that eye, compared to the other.  If so, the eyedrop could be stopped in the other eye as well.

P:  Can a toddler with IOPs of 17 and 18 mm Hg benefit from exercise, such as walking and climbing?

Dr. Rick Wilson:  I don't see why the beneficial effects of exercise would be reserved only for adults, but that is my impression, not proven.

P:  Do you suspect there is any relationship between stress and IOP?

Dr. Rick Wilson:  All my patients think so, and one study found that patients, after taking visual field tests, had higher IOPs than usual, which is an indirect indication of stress raising IOP. Stress is so subjective, however, that the relationship with IOP is hard to prove.

On September 7, Dr. Werner discussed "Other Diseases and Glaucoma" in the Chat room. Click here for highlights of that meeting.

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