Blood Thinners and Altitude and Strenuous Exercise

[spotly]

Anyone here on blood thinners? Any idea how that affects the body during strenuous exercise like one would get with a hideous car to car like say Mt. Sir Donald?How about affects from altitude? I'm new with this crap and trying to figure things out. Hoping to get some first-hand info.

 

Domo Arigato

[jordansahls]

What kind of blood thinners are we talking about here? Are you taking a small blood thinner like aspirin, or something more serious like coumadin?

 

 

[spotly]

I'm on 4 mg of coumadin. At this point it looks like it'll be long-term, probably permanent. I've been told that once the injury has healed and my clot hardens up, I should be able to return to normal activities but my docs were pretty vague on their definition of strenuous...the old "just don't let yourself get too tired" thing. That'll get me a few hundred yards up the trail lol. Just wondering if the thinners themselves will do something to the blood to reduce stamina. From what I hear from some people, usually not, so then I gotta wonder about altitude issues.

[JosephH]

You might want to post up over on Supertopo.com; it's got a much higher density of craggy, self-abusing old farts with a full Mayo Clinic range of ailments...

[John Frieh]

I alternate between fish and plant oils to ensure my omega 3s and 6s are balanced which will both thin your blood but I've never had an issue at altitude... Then again oil doesnt exactly come with a warning label where as your prescription does...

 

I'd ask Kevino on this board what he thinks

[Dane]

From experience with family members on Coumadin I would be more worried about a cut or other minor injuries, like a impact bruise, first. Then may be how it effects your endurance.

 

One of my buddies on a steady diet of Coumadin has done several 8Km peaks previous and continues to get out with what appears to be no slowing down. But last trip we did together I was a little surprised he would be on Coumadin the rest of his life as well. Not sure he understood the risk (or that I do) and we haven't talked about it.

 

My father in law is on Coumadin and has ended up in the hospital several times from a simple nose bleed. I've had students on Coumadin end up with some pretty terrible injuries from impact bruises that didn't/wouldn't effect someone not on medication.

 

None of those were in the mtns...and have to say if they had been I would have been a little freaked getting it all managed, if you could out side a clinical situation.

 

As John suggests..no warning labels on fish oil....but this is one I would get experienced and expert medical advice on and may be ask about other side effects.

[jordansahls]

You may want to exercise a bit of caution. Travel to altitudes of over 2400m have been shown to lower patients INR's below theraputic levels. It sounds like bleeding out isn't so much of a risk as forming a potential life threatening emboli.

 

Here is a link to an abstract:

Warfarin and altitude

[JosephH]

You might also want to consider carrying a few QuikClot or similar packs - they come in various forms and sizes from first aid websites (maybe REI as well but I don't know).

 

Blood clotting products

[spotly]

Thanks for all the excellent info. I really appreciate it. Never heard of the quick clot things .. Great advice.

 

You may want to exercise a bit of caution. Travel to altitudes of over 2400m have been shown to lower patients INR's below theraputic levels. It sounds like bleeding out isn't so much of a risk as forming a potential life threatening emboli.

 

Here is a link to an abstract:

Warfarin and altitude

 

Thanks very much for this link. I was looking at this from an injury management and performance perspective and didnt even consider the affect on INR! One more thing to discuss with my neurologist.

[kevino]

Spotly,

 

The link that Jordan gave you is interesting, but I'm thinking not directly applicable to your situation. Their research subjects seem to be taking coumadin for afib. Whereas you hint that you need to talk with your neurologist, which I can only assume means you had some sort of head injury/accident (clot in your brain, tia, stroke, etc). I'm just guessing but you should only pay attention to research articles that are relevant to your specific ailment since blood thinners such as coumadin have multiple uses.

 

Secondly, if you just got on coumadin you really shouldn't be doing too much until you can make sure you have a good baseline of your body being able to keep your INR in the therapeutic range. Hopefully that makes sense.

 

That is only the internal physiological issues so far...

 

Next, as some have alluded to, are traumatic injuries. Having your INR in the therapeutic range, (elevated for the normal person), puts you at a higher risk for hemorrhaging, both internally and externally. Knowledge of how to treat the external ones will be important. On the other hand, getting yourself to a hospital as quickly as possible for the internal ones will be more important.

 

I'll do some research when I go back to work next week.

 

[kevino]

To answer your main question, warfarin works but inhibiting clotting agents, so I don't believe there is a direct corralation between that and endurance reduction but I'll do some research and see what I can find out.

 

article #1

 

2

 

british doc's

[ClimbingPanther]

The subtherapeutic INR study is interesting but not applicable because of the study design. Any time you hear the words "odds ratio" you must realize that no cause-effect conclusions can be drawn from the study. The change could be for many confounding reasons such as changes in activity, diet, forgetting to bring meds on vacation, forgetting to take meds on vacation, etc. Retrospective studies are good for spurring research, but generally not for making important decisions.

 

Offhand, I'd say there's little reason to expect adverse affects from altitude or exercise alone, but of course as has been said already, a minor injury could become life threatening, and a more serious injury could be fatal. If you're hiking/backpacking/etc with a low risk of injury, I'd say have a blast. If you're lead-climbing, I'd reconsider. By the way, you would do well to have a look at all the lovely and unexpected drugs, supplements, foods, etc. that mess with warfarin's metabolism and trafficking in the body.

[spotly]

Thanks for taking a look at this. Great info for me to use when discussing my issues with the doc next appointment. Kevino, you're correct that mine is an injury...a tear in the lining of the carotid artery that led to a clot then quickly to total and permanent blockage. I was fortunate to have fairly mild impairment, which I'm well on the way to mending and should be hiking by end of year and hoping to be climbing by next season, including leading. I'll definitely discuss the risk factors of that with my doctor.

[jordansahls]

Thanks for the clarification everyone. Just to scratch a curios itch, doesn't it make sense that travel to altitude would decrease INR? I would think that the hypoxic response mechanism would cause an increase in RBC production. However, coumadin works by inhibiting the vit K pathway. I would also think that the INR wouldn't change much at all because vit K is the rate limiter in the response. So is there more research out there on this subject?

[kevino]

Spotly, that's some serious stuff - glad to hear you're recovering well. Those carotids can be a fairly common source for throwing clots. Like I said before and as climbingpanther agreed with, I doubt the coumadin will affect your performance at altitude. I think getting back in shape after your injury and maintaining fitness while on coumadin will be your biggest challenges.

 

Jordan, if I understand your hypothesis correctly you are saying that the INR would decrease due the relative rise of RBC? That assumes the INR values take into consideration the levels of RBCs, which I'm not familiar enough with to know. Sounds like you should do more research and let us know! haha

[iluka]

Thanks for the clarification everyone. Just to scratch a curios itch, doesn't it make sense that travel to altitude would decrease INR? I would think that the hypoxic response mechanism would cause an increase in RBC production. However, coumadin works by inhibiting the vit K pathway. I would also think that the INR wouldn't change much at all because vit K is the rate limiter in the response. So is there more research out there on this subject?

 

Hypoxia itself should not lead to alterations in the INR given the way that warfarin works. Warfarin works by blocking the effects of vitamin K on the liver's production of important clotting factors. There is no clear evidence at this point about the effect of hypobaric hypoxia on synthetic liver function so it's unclear how hypoxia might affect the liver's ability to make important clotting proteins.

 

The key issue for Spotly is whether his INR will get out of the therapeutic range (either too high and associated with an increased bleeding risk or too low and associated with an increased risk of clots and stroke) during his climbing trips. I doubt hypoxia has much to do with the risk of that happening but think it is more likely due to what happens to his vitamin K intake during his longer climbing trips (e.g., multiday trips). Changes in dietary intake of Vitamin K relative to the normal intake at home will likely occur as a result of having a very different diet on the trail. This will lead to alterations in the INR (either sub- or supratherapeutic depending on whether he gets more or less vitamin K in his trail diet).

 

My hunch is that the findings of the study referred to in an earlier post about changes in INR in patients with atrial fibrillation around travel to high altitude were due to changes in dietary intake of vitamin K that occurred with travel rather than hypoxic exposure. This study is relevant in this discussion even though it was in patients with afib. Regardless of the reason you're taking warfarin, the key issue remains the same... will the INR go up or down with travel to high altitude.

 

Of course, the biggest risk, as others have noted, remains the risk of significant bleeding with any trauma. A helmet is a must and the threshold for putting it on should be very very low.

[iluka]

Jordan, if I understand your hypothesis correctly you are saying that the INR would decrease due the relative rise of RBC? That assumes the INR values take into consideration the levels of RBCs, which I'm not familiar enough with to know. Sounds like you should do more research and let us know! haha

 

The hypothesis in this case is wrong. The hemoglobin concentration or hematocrit (both of which rise with long enough stays at high altitude) will not affect the INR. The INR is a function of other factors. The liver uses Vitamin K to make proteins that affect the major blood clotting pathways. Warfarin (aka coumadin) works by blocking the effects of vitamin K. This decreases the liver's ability to synthesize enough clotting factors and the blood's ability to clot and stop bleeding is impaired.

 

If someone is taking warfarin and the markedly increases their intake of vitamin K, this will counteract the effect of warfarin to some extent and make the blood clot easier. If, however, someone's diet changes and their intake of vitamin K goes down, or they take antibiotics which kill bacteria in the GI tract that normally produce Vitamin K, then the effects of warfarin is enhanced and the blood is thinner than it should be.

[kevino]

Thanks iluka, that is what I assumed as I alluded to, but didn't know for sure.

 

While this is an interesting subject, I doubt there will ever be any money for a research project about high altitude climbers on blood thinners.

Edited July 18, 2011 by kevino

[iluka]

While this is an interesting subject, I doubt there will ever be any money for a research project about high altitude climbers on blood thinners.

 

The money for such a project is likely not out there but it's not an insignificant question. If you look beyond the climbing community and consider the wider group of people traveling to high altitude to ski at resorts, trek to places like Macchu Picchu and do a variety of other things, there are actually a lot of people on warfarin because of atrial fibrillation or deep venous thromboses who travel to or would like to travel to high altitude. Understanding what happens to their INR on such trips would be important as the implications of a recurrent stroke or DVT or bleeding can be pretty severe in some cases.

[jordansahls]

Thanks for the clarification. It's an interesting subject no doubt. In my limited expirience, I have been led to understand that determining a patients INR can be difficult which is why, when a safe theraputic range has been reached, it is highly unadvisable for patients to switch their eating habits (example, no large kale salad if it's not your norm, to much vit k, ect). It seems like a major difficulty with these studies is using the INR since it seems to be such a moving target even under "normal" cirsumstances.