Hi. We've been closely studying my NTG with OCT for many years and found some surprising results regarding the connection between strenuous physical activity and progression, parts of which were presented at ARVO 2024. Questions about physical activity and glaucoma are common, with the typical recommendation being to avoid head-down posture and Valsalva, but we found a much broader, quantitative connection that included more common activities. It's likely that most others with NTG/OAG are much less susceptible to these effects, but our findings also suggest that, in some cases, especially with aging, strenuous activity may become a key modifiable risk factor.
Strenuous Activity, Microleaks and Glaucoma Progression
Reporting a case of unprecedented 3-year, weekly, hi-res OCT tracking of NTG with good IOP control, resulting in 6 key findings:
1. progression, as measured by RNFL loss, was discontinuous, sector-specific, and attributable to strenuous activity (SA)
2. activities included common home and yard projects, although head-down posture and Valsalva were many times riskier
3. multi-day SA clusters (SACs) greatly increased RNFL loss
4. took 8 weeks after each SAC for RNFL loss to complete
5. RNFL loss was proportional to the cube of SA time and intensity (2x SAT, 8x loss)
6. ONH microhemorrhages (microleaks), triggered by SA, likely accounted for RNFL loss
These findings suggest that, in some cases where IOP is well-controlled, strenuous activity may become the key modifiable risk factor for glaucoma progression.
I’d be happy to answer any questions you might have about the report.
(updated report site link)
Written by
watiop_dan
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Hi. Second page of links site has an "Abbreviations" slide link at top. Yes, the link and all the links on the site are safe. We've posted this to multiple forums without issues.
NTG = Normal Tension Glaucoma
OAG = Open Angle Glaucoma
RNFL = Retinal Nerve Fiber Layer (becomes thinner with progression)
ONH = Optic Nerve Head (Optic Disk)
SA = Strenuous Activity; SAC = SA Cluster (a multi-day group of SAs)
Hi. The "About Activity" page on the site describes how strenuous activity (SA) was defined, with links to some tables in the scientific presentations (there is also a short Guide video for that page in the playlist on the first page of the site). Briefly, SA includes moderate and vigorous activities/exercise, as typically defined, plus head-down posture and Valsalva. We also accounted for activities done at higher temperature/humidity. Activities were ranked as to their relative intensity (risk). Activity time x intensity (= SAT) was then found to be related to progression, as measured by RNFL loss (ΔRNFL ∝ SAT-cubed). (This is the first time that anyone has studied a subject close enough to see this relationship - see the "Unprecedented" video or pop-up which explains how unique this research is.)
This variation in SA risk is probably generally applicable, but whether it affects you depends on a second thing, your personal susceptibility to SA (which we quantified as the "strenuous activity coefficient", ksr). For example, deep snow shoveling was more risky than push lawn mowing, but just how risky a half hour of deep snow shoveling is for you depends on your personal susceptibility to SA. And if you already have good IOP control, with minimal progression, and are doing such activities, then your susceptibility (ksr) must be very low -- and you may only need to worry about the most risky activities like head-down posture and Valsalva (which you were probably already warned about). However, if you still have significant progression with reasonable IOP control, then SA may be playing a role in that.
We also, for the first time, developed a simple model that explains all this, based on observing that SA-triggered optic nerve head (ONH) microhemorrhages (MH), which appeared to be the direct cause of RNFL loss (progression). In other words, the snow shoveling can cause an ONH MH, which bleeds a certain amount, potentially causing a proportional amount of RNFL loss (nerves are damaged when exposed directly to blood components). This also explained why the relationship between SA and RNFL loss was found to be cubic, since larger MHs both leak at a faster rate and stay open longer (i.e., the longer and more intense the SA, the bigger the leak, and much bigger the leak volume and RNFL loss).
Caveat: This mechanism very likely applies to the study subject (a typical NTG patient), but may not apply in other cases, such as to those with OAG. That will have to be determined. On the other hand, the known link between progression and head-down posture or Valsalva makes us suspect that this mechanism is much more common than currently thought.
This is interesting and hugely significant if applicable generally. I have NTG, was diagnosed about 15 years ago and have maintained an exercise regime involving strength exercises and gym work for all this time. My vision continues to deteriorate, am I interpreting this report correctly in that such exercise could be harming my eye health?
Hi. See my response above to judetheobscure22, giving an overview of the role of strenuous activity (SA), your personal susceptibility, and the underlying model based on microhemorrhages (MH).
Yes, based on what we found, the combination of NTG + SA + progression makes it plausible that SA is driving your progression, specifically by creating MHs that damage axons (nerves). The "About Activity" page describes how SA can "add up" to create this risk, and what you can do to lower the risk. The "About Microleaks" page describes the likely underlying mechanism. And the "Strategy" page describes how to check for this mechanism, and what to do about it.
Another interesting thing is that aging probably increases this risk by generally increasing the leakiness of blood vessels -- see the information "i" pop-up on the bottom of the "About Microleaks" page. So your risk is likely increasing by simply getting older -- related in part to lower sex and growth hormone levels that affect wound healing and vessel strength. The "Questions" page also has some discussion of these issues. The final note on that page, about choroid thinning with SA, is also interesting, suggesting there is no simple relationship between exercise/SA and ocular blood flow.
(Tip: watch the Guide video for a page before trying to decipher it)
Hi there. Thanks for sharing this. I would be careful with cutting out all exercise, as we do know that exercise can be beneficial for glaucoma as well as providing other health benefits. We always recommend light exercise for people with glaucoma (anything like walking, jogging, cycling, swimming are all great options).
We do already advise to avoid putting your head below your heart, or anything too strenuous (such as weight lifting or HIIT). We do need more robust evidence on this area before we are able to advise on the correlation between exercise and glaucoma progression. For now, we do recommend that people with glaucoma do continue to participate in exercise that they enjoy. As always, please don't hesitate to contact the helpline on 01233 648170 or helpline@glaucoma.uk if you have any questions.
Hi. There's nothing in our report to suggest one should "cut out all exercise". It's all about determining one's susceptibility to strenuous activity (SA) and how best to deal with that. We found that common recommendations (including "jogging, cycling, swimming") may be quite dangerous in some cases, without reference to how or how long those activities are being done.
This report provides unusually "robust evidence" for this individual, given the time and closeness with which the subject was followed (see the "Unprecedented" video or pop-up). Whatever conclusions/theory the glaucoma world eventually comes to about activity and glaucoma will have to account for this case, and others like it. However, we already provide a model that accounts for a wide range of responses (personal susceptibility), so it will be interesting to see if that can be improved/replaced by something better as more research is done -- a big problem being that such research is very difficult to do, as we describe in the Unprecedented video.
Based on our findings, we're (humbly) suggesting that leaders in the glaucoma community would be wise to reorganize their thinking a bit about the risk of SA/exercise, acknowledging that there is no one-size-fits-all approach, and that even common activities can be quite dangerous in some cases, depending on both susceptibility and how, and how long, those activities are done. The challenge is to thread-the-needle between overall fitness and risk of progression, but this requires a good understanding of the link between activity and RNFL loss, which we've significantly advanced with our study (even providing a simple underlying mechanism to explain the quantitative relationship).
Thanks Kieran for the opportunity to have this exchange of views. It should help others understand better the limits of what's currently known about activity and glaucoma.
Thank you for sharing this. I would like to add that people with pigmentary glaucoma/pigment dispersion should avoid jogging, but other gentle exercise such as swimming, walking and cycling (domestic, not the strenuous uphill competitive cycling) are acceptable forms of exercise, but we always recommend that before starting on an exercise program to speak to your consultant. They will never discourage exercise.
This is a big shock. I have normal pressure glaucoma. No one advised me to avoid strenuous activity, or the 'head down' posture. I don't understand why. I have been carrying on with life as usual since my diagnosis 2 years ago and my sight has definitely deteriorated.
Hi. Can you tell us more about your lifestyle/activities, and how your progression is being measured? Generally, for NTG, it's (becoming more) common to be told to avoid head-down posture, Valsalva (such as holding breath while straining during exercise, blowing a wind instrument, etc.), and extreme exertion (i.e., stuff where pressure in your head seems high). Our report confirms all that, while adding a few more wrinkles.
I moved house 10 months ago. I am the sole homemaker - constantly lifting heavy objects, moving things. I have two school age children. I am responsible for all housework. We have two dogs.
For example, I leave my room at least about 10 times a day. This house we have moved to, well this door doesn't shut properly. So I bend each time and drag a heavy packing carton to block the door. For the past 10 months.
So what makes you think your sight has deteriorated significantly? Just asking since one can't tell how susceptible you may be to strenuous activity (SA) without having some measure of progression (sight loss, RNFL loss, visual field decline, etc.).
If susceptible, and IOP is well-controlled, what we found (not medical advice) was that risk could be managed (see "About Activity" page on site, first viewing the Guide video for the page to help you understand it) by either:
- avoiding riskiest types of strenuous activity (the common advice)
- increasing time between activities (giving more time for healing)
- reducing overall total strenuous activity time (= SAT = sum of time x intensity)
The good news is that small changes to SAT made a big difference to progression (-20% SAT reduced progression in about half for the study subject, due to the cubic relationship, 0.8^3 = 0.5, likely having to do with how microhemorrhages leak), which might be accomplished by simply avoiding the riskiest activities.
The vision in my left eye is perceptibly different from my right eye. Clarity fluctuates. It's better in the morning, but by evening i cannot read at all with my left eye. It's like a white film comes over my eye, blurring everything. I only noticed the fluctuating vision last week. So I went to the GP on Tuesday and he is referring me to the Ophthalmologist.
The last time i was checked, i was told that my eye pressure was normal but the glaucoma had deteriorated.
The immediate problem with LE doesn't sound like typical NTG/OAG glaucoma, but Ophthalmologist can probably tell you what's up with that. Regarding longer term deterioration, would be good for you to find out what that means exactly (i.e., how much loss per year, by some measure), and have them tell you how that compares to healthy normal (for example, typically less than 1 µm/yr global RNFL loss). In other words, get some idea just how risky things are -- the more risky, the more you might want to moderate activity as described -- the less risky, the less to worry about.
Another issue that we talk about on the "Questions" page is estrogen (estradiol) loss in women going thru menopause playing a role in progression (possibly affecting men too as testosterone falls with age). So you may want to make sure to be on some sort of HRT (estrogen replacement) if/when you go through that, where low-dose transdermal estrogen replacement is generally considered safe for most women. (Logic being estrogen loss contributes to more leaky vessels, increasing microhemorrhage risk, and subsequent RNFL loss -- there's also lots of other research supporting a link between estrogen loss and glaucoma progression in women.)
I remain interested in your study's definition of strenuous activity. My own definition and one that seems common elsewhere would include running, singles tennis and badminton as strenuous. Your study seems to focus on more heavy lifting type activity. I'm really hopeful (speaking personally,!) that it's the lifting aspect that's problematic as I've already had to abandon any thought of playing my French horn again so really do not want to have to consider reducing the sports I love.
Hi. The activities we initially studied were grouped into "moderate" or "vigorous", following the typical definition of those (I'd link you to a references slide, but I don't see a way to simplify the link here; it's slide 1-22, 22nd slide in 1st presentation, which you can easily get to on the site). So, for example, push lawn mowing was moderate, whereas deep snow shoveling was vigorous. We later had the opportunity to evaluate the risk of (pure) moderate Valsalva, which was found to be many times riskier (4x vigorous), and assumed that more intense Valsalva was even riskier (8x vigorous). (Activities involving head-down posture were also riskier.)
This raises the question as to whether Valsalva within moderate or vigorous activities is the main risk, which we speculate about in the "Vessel Leakage Exposed" presentation. Meaning, as you suggest, that risk from these activities can be reduced by avoiding Valsalva (and head-down posture) when doing those activities. I think that is largely correct, since it is the spikes in venous pressure (VP) that are likely often causing the microhemorrhages (MH) to form, with subsequent RNFL loss. However, it's still true that "common activities" can cause progression (RNFL loss), since the way people do common activities typically involves some Valsalva. Also, it's not clear whether intense exertion w/o Valsalva is completely safe, since that too often involves pressure spikes (BP/VP/IOP) that may trigger MH and RNFL loss. Basically, anything you're warned against doing to prevent cerebral hemorrhage, aneurysm rupture, Valsalva retinopathy, etc., likely also applies to preventing MH-driven glaucoma progression, since you're dealing with a similar type of vessel vulnerability. (Notice too that it really isn't just about IOP, rather how pressure spikes of all sorts can break an already-weakened vessel.)
The other issue is time. Each activity had an inherent relative risk (intensity), but total risk was equal to time x intensity (SAT, strenuous activity time). So unless the activity has zero relative risk (walking probably qualifies), it can always be done for a long enough time to equal the total risk of more risky activity types done for shorter times. That makes sense (and is what we observed). If you spend an hour playing tennis (and hard to believe no Valsalva in that!), then that will add up to the risk of a certain number of minutes of standing on your head, or playing a wind instrument, etc. The idea again being that you're walking around with already-weakened vessels in your optic nerve head (ONH), which will break under stress, releasing blood components that will damage/destroy nearby axons. It's like managing a bad knee: obviously you don't want to put a great deal of short-term stress on it, but you're probably also going to have a problem taking a lengthy hike.
The next issue is clustering. We found that the smallest microleaks producing RNFL loss still took several days to heal (to stop leaking fluid). This meant that activity on nearby days (activity clusters, SACs) had to be summed to get total risk, because activity on following days was making existing leaks larger. So if you did 1 hr of tennis on successive days, then that would be counted as 2 hr SAT. This matters because risk grew as the cube of SAT, meaning counting the days separately would have a relative risk of only 2 (1^3 + 1^3), but as a cluster risk rises 4x to 8 (2^3). That's because bigger leaks produce much bigger leak volumes (higher flow and duration), with much more potential RNFL loss. So, interestingly, it's not just about whether what you're doing causes a microleak, but whether what you're doing is adding to the size of an existing microleak. It's like the brain aneurysm has already ruptured, and wondering whether playing tennis will make it worse.
Summarizing, regarding relative risk, it's probably the case that specific activities can be objectively ranked with respect to their relative risk of triggering MH and RNFL loss. The ranking may be largely, but not completely, related to the amount of Valsalva and head-down portions of the activity, but with extreme exertion probably also being risky. We did some initial ranking based on closely tracking activity and RNFL loss in a susceptible subject, but more work could be done to better define relative risk for various activity types -- a major issue though being how difficult it is to collect such data, as described in the "Unprecedented" video/popup.
The second part to all this is what your personal risk may be -- meaning how many leaks you may have, and their relative leakiness. We expressed that as a proportionality constant, ksr, in the relationship ΔRNFL = ksr SAT^3. I have a big ksr, you probably have a much smaller one, but the underlying mechanism for RNFL loss may be the same. But we just don't know yet how universal this mechanism is in NTG/OAG (one of our "Questions").
All of this probably implies that no moderate or vigorous activities are completely safe (you can always do them in a way, or for a time, that is risky). Rather one has to manage risk, taking into account both the relative risk of activity types, and one's personal susceptibility. The goal being to reduce progression to an acceptable level (not zero).
Hi. We added an informational "i" popup, What is "Strenuous Activity"?, to the Overview page where "strenuous activity" is first used. I'll also add a corresponding video for that later, given its importance. Let me know if you think something more is needed. Thx.
Another way of looking at Jude's question related to relative risk of activities is to note that the relationship ΔRNFL = ksr SAT^3 (cubed) is simply saying that your progression may be a strong function of your current levels of strenuous activity (assuming IOP is already well-controlled). Meaning that if you have some notion of your rate of progression (rate of vision loss, RNFL loss, etc.), and you judge that rate to be too high, then you might consider modestly reducing total SAT, where even a 20% reduction may cut loss by 50%, as shown in image. This reduction can either be done by reducing the most risky activity types (like Valsalva or head-down), or by increasing time between activities (giving more time for leaks to heal before making them larger), or by reducing total activity -- and all done without ever calculating values for ksr or SAT, or knowing exactly the relative risk of different activity types.
Interestingly, the cubic relationship itself, with very low impact at one end, and very high at the other, helps create the illusion that SA either matters much or not at all, or that some activities are completely safe, while others are quite risky. But that has never really made much physical sense. More sensible that effects can "add up" to increase total risk; that it matters how long you're doing each activity; and that most activities are often a complex mix of more or less risky stuff, the net effect of which isn't going to be either "completely safe" or "quite risky".
We'll have to see how widespread the SA-triggered, MH-driven mechanism is, but its ability to make sense of so many of the details (location, fluid, timing, clustering, etc.), plus the previously studied association of Valsalva and head-down posture with ocular & cerebral hemorrhages, plus the strong association of retinoschisis and larger optic disk hemorrhages with glaucoma progression, suggests we may be on the right track.
Here's the associated image from "Strategy" page referred to above. The "i" popup shows subject's current strategy, and the "safe zone" is pointing out how minimal RNFL loss was achieved when microleak durations were kept below 1 week.
What prompts Valsalva during activities like running? It seems from your earlier reply that it's the Valsalva that causes the problems. Unfortunately I can't derive any comfort from the reduced risk of playing for shorter periods of time as I play or run every day per week except one and on non-work days I often play for four hours or more!I also note your observation about hiking - I went on a 20 mile hike a couple of weeks ago :/
I do have a haemorrhage noted, I think the consultant said on the optic nerve, so obviously I'm quite at risk. And I do notice a bit of blur occurring sometimes, part way through a match. I'm having an iridotomy next week. Let's hope that helps!
Hi. It would be the start/stop, change direction/posture, exhaustion parts of tennis/running that I'd be worried about (rupturing a vessel, creating a microleak). Seeing a hemorrhage (blood) in a fundus exam may mean that there are multiple unseen microhemorrhages (MH, time-varying fluid pockets, blood caught in tissue) within the ONH that might be detected with OCT. OCT can also track RNFL loss precisely over time (if done well). High IOP (purpose of the iridotomy?) would increase ONH damage (lower OBF, higher LC stress), making you more susceptible to activity-triggered MH -- but once damage is done, you may still be susceptible to activity-triggered, MH-driven RNFL loss regardless of IOP (as in my case).
The #1 thing I would do (other than dealing with high IOP) is to begin tracking RNFL thickness precisely (VF is a less precise alternative), even if you have to pay extra for more measurements (having just a few noisy measurements leads to over/underreaction). It will take some time to see real changes (to average out the noise), and you may lose some RNFL (vision) during that time (continuing to do your normal activities), but it's much better to know what's happening (what your susceptibility is) rather than to be guessing. In other words, imho, you can afford to lose a bit of vision if the payoff is better long-term control, with optimal activity management.
Once you know what your loss rate is, you can adapt your activity levels (and IOP) to that, as discussed earlier. After that, there is aging to worry about, as MH becomes more likely with age. In other words, as you feel yourself becoming generally more physically vulnerable with age (healing more slowly), your ONH vessels are also becoming more vulnerable. (See the "i" popup at bottom of "About Microleaks" page describing possible dramatic effect of aging on MH risk. Also the discussion of sex & growth hormones on the "Questions" page.)
Caveat: That's what I would do, not medical advice. A typical eye doc will probably simply lower IOP, do minimal tracking (a cost issue), and may note that certain types of activity may be risky for some patients. But we can do better tracking & activity management.
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