Exercise and Glaucoma: Weight Lifting
I have never seen a single resource that recommends weight lifting as a means of lowering intraocular pressure (IOP). In fact, I think the conventional wisdom is that weight lifting would not be the right kind of activity to engage in for someone with elevated IOP or glaucoma.
One way to categorize exercise is as either aerobic or anaerobic. Weight lifting is usually anaerobic. Therefore, when one reads a statement such as “while studies show that aerobic exercise can lower intraocular pressure, other forms of exercise can increase pressure”, one naturally concludes that weight lifting will raise IOP.
On the Commonly Asked Questions page at Glaucoma Associates of New York, they address the issue of exercise and IOP or glaucoma in two questions. Both repeat the exhortation that aerobic exercise lowers IOP and non-aerobic exercise raises IOP. Here are those two items:
Does exercise lower intraocular pressure?
A: Aerobic exercise can lower intraocular pressure for a time. However, other forms of exercise can increase the pressure. You should check with your eye doctor before starting any exercise program.
Do nutrition and exercise affect glaucoma?
A: A healthy diet coupled with a daily routine of exercise is a good prescription for everyone interested in good health. But remember, every patient is different. Before making any drastic change in your diet, it is wise to communicate that intention to your doctor and discuss the pros and cons. The same advice is true for embarking on a new exercise program. While studies show that aerobic exercise can lower intraocular pressure, other forms of exercise can increase pressure. So, if you're a glaucoma patient, it's especially important to check with your doctor before making any lifestyle changes. Such changes could have an impact on the test results your doctor relies on to evaluate the success of your treatment plan. You can find a helpful discussion of diet and glaucoma in "Coping with Glaucoma," by Edith S. Marks (Avery-Putnam-Penguin, 1997).
I have known that I have glaucoma for over 3 years now. I have known that I have pigmentary glaucoma for a bit less than 2 years. All this time, I assumed weight lifting was not a good activity for me.
Recently, I decided to quantify the extent to which weight lifting was “bad” for my eye pressure. (The whole idea to do this test was just a lark.) My IOP was measured immediate before I began weight lifting. The values were 15-L and 20-R (meaning my intraocular pressure was 15 in the left eye and 20 in the right eye), which is not uncommon for me at this time.
For the weight lifting I performed a series of exercises including:
• Bench press
• Lat pulldowns
• Barbell squats (full depth, official powerlifting style)
I finished off with lying tricep extensions to failure. In this exercise, I was lying on a flat bench with my head hanging off the end. I held the weight in my hands with my arms extended toward the ceiling and I lowered the weight to my forehead with my elbows pointed upward.
The weight lifting session wasn’t long because I didn’t do a lot of sets. However, I felt it was probably going to have such a negative effect that I was afraid to do any more than what I did.
I was sure my IOP would be elevated. All the exercises involved strain. I could feel my face tightening many times during the workout. But finishing off with the lying tricep extensions would be the final blow, I was sure.
My IOP was measured immediately after finishing the workout. The time span between dropping the weight on my last exercise and the first IOP measurement was less than five minutes. (It was more like 1 minute.)
The values were 13-L and 16-R.
I repeated a similar test two days later. The results were similar:
Before weight lifting: 15-L and 20-R;
After weight lifting: 13-L and 17-R.
About a week later, I repeated a similar test. But in this case, the weight lifting was preceded by some mild aerobic exercise:
Before activity: 15-L and 20-R;
After cycling and weight lifting: 14-L and 17-R.
What’s interesting is that aerobic exercise also lowers my IOP, as the conventional wisdom suggests it should, but the drop in IOP is no greater than the drop in IOP from weight lifting. For example, after a 1 hour aerobic exercise session, my IOP values were 13-L and 16-R. These are the same IOP values I have seen after weight lifting. However, I have had a few aerobic sessions that did not result in a significant drop in IOP (and I have even seen a slight, but insignificant rise in IOP after aerobic exercise a few times). So far, however, all weight training sessions have resulted in IOP drops of the magnitude described above.
I am not ready to make any kind of conclusion for myself yet. (And all of this can only be said to apply to me, afterall.) I plan to repeat many more tests. I would like to have at least 15 to 20 tests of both weight training and aerobic exercise.
However, the results so far have given me a new question to investigate. This question is, Does weight lifting produce an IOP lowering effect that persists for a significant length of time after the exercise session ends?
In addition to that question, I would like to study some variations on the weight lifting theme.
For example, I have tested a couple variations already. I performed individual weight lifting exercises and measured the IOP altering effect of that single exercise. Preliminarily, it seems that certain exercises might have a greater IOP lowering effect. In fact, I believe I have detected a significant IOP lowering effect (of the same manitude shown above) from performing a very limited number of sets of a single exercise (total length of workout: about 5 minutes). This will have to be investigated further, so I don’t want to say more right now. If I cannot repeat this effect, I’ll conclude it was due to chance.
I should clarify that there are at least two valid perspectives on weight lifting and IOP. One thing that is important to understand is the IOP during weight lifting - while actually performing the exercises. This seems to be the issue that has received the most research interest.
If my experience holds for others, then maybe we'll see some research done with another perspective: the effect of weight lifting on IOP over the hours following the activity.
On some days I believe I have seen the IOP-lowering effect of exercise last the entire remainder of the day. At other times, I have seen it last only an hour or so. There are certain activities that increase my IOP, so in order to better understand how long the IOP-lowering effect of weight training persists, I have to better control the other activities. So far, I have not done that. But it is my intention to perform tests to quantify the length of time the positive weight lifting effect lasts.
The IOP readings were all taken via non-contact tonometer. The procedure is to take 3 to 5 individual readings for each eye. If the variability of the first 3 readings is large, additional readings are taken. (Typically, up to 5 readings may be taken, although some tests have used 6 readings in an effort to see if that increased accuracy - it did not. Three readings seems to be just as accurate as 4, 5 or 6.)
The reported value for each eye is the mean of the individual readings. If one or more readings show the effect of a venous pulsation (or eyelid blink, etc.), they are retained. Attempts at using harmonic means, geometric means or interior means (in an effort to reduce any confounding effects) has, so far, not resulted in any advantage. However, the complete data sets are being retained so that additional processing can be applied whenever desired.
I have recently begun repeating the measurements with a second instrument. First, the procedure described above is followed with instrument #1. Then the entire procedure is immediately repeated by taking 3 to 5 individual readings for each eye with the instrument #2. The order of the readings (left eye or right eye first) and the order of using the instruments (#1 first or #2 first) are alternated.
I have also performed three direct comparisons of this non-contact tonometry against the Goldman-style applanation tonometry, and the reported values all use a correction factor that was determined to bring the values into agreement.