Episode 497: Blood Clot Defeated & Return To Training
I reached the end of my journey with the blood clot I discovered at the end of June. I learned a lot through the process, along with information about my personal risk for blood clotting. I unpack all of that and share my return to training.
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Summary:
Initial Incident (Late June)
Planned to race a 100-miler at the Pettit Center in Milwaukee.
On a shakeout run the first morning after flying in, left calf tightened progressively; cut the run short and dropped out of the race (assumed minor calf strain based on prior experience).
Symptoms didn’t match a typical strain: constant low-level throbbing regardless of activity/position.
Went to urgent care for ultrasound → confirmed large blood clot (DVT) from ankle to mid-thigh.
Sent to ER: clot was extensive but hadn’t reached the pelvis and was not fully occlusive (pulse still present in foot). Prescribed Eliquis (blood thinner) at high dose (10 mg twice daily) and released; returned to Austin for follow-up.
Medical Follow-Up & Decisions
Saw primary doctor quickly, then hematologist and considered vascular surgeon.
Key decision: surgical removal vs. letting it dissolve on blood thinners. Choose a conservative path after symptoms improved rapidly (throbbing gone in 1–2 days; swelling nearly gone in ~1.5 weeks). Blood thinner reduced to 5 mg twice daily.
Extensive lab work ruled out other serious causes (e.g., cancer); all looked good.
Diagnosed with Factor V Leiden genetic mutation → elevates clotting risk 3–8× (depends on inheritance and other factors).
Risk Factors & Insights
Higher personal risk due to genetics + ultrarunning lifestyle: travel/flights, dehydration, extreme physical stress, post-race immobility, injuries reducing mobility.
Reflected on past races (e.g., 2014 World 100K in Doha) where multiple risk factors stacked heavily.
Will stay more vigilant around these triggers going forward.
Recovery Timeline & Monitoring
~2 weeks off all training; ~4 weeks off running. Cleared for low-impact (cycling, elliptical, hiking) early; running resumed around the 4-week mark on thinners.
Running consistently for ~3 weeks at time of podcast with no ongoing symptoms or differences between legs (brief early low-level “cramping” that resolved quickly). The clot largely dissolved.
Tracked data: HRV dropped sharply and stayed low for 1–1.5 weeks, then gradually recovered over 5–6 weeks to normal range. Resting HR elevated ~10 bpm for a few weeks before normalizing (attributed to body healing the clot).
Treatment Plan Going Forward
Remain on Eliquis 5 mg morning + evening at least through the end of the year; reassess with a hematologist then.
Possible long-term options: continuous very low-dose blood thinner, or proactive use only around high-risk situations (travel, injury, post-race, etc.). Continuous low-dose is currently favored by his doctor as more reliable.
Minimal side effects noticed so far, but increased caution around falls/head impacts due to bleeding risk.
Training & Racing Plans
Building back gradually (mindful of the ~30 days off impact loading to avoid injury). Currently focusing on short high-intensity sprints and low-volume short intervals to rebuild speed reserve.
Hasn’t decided on another 100-miler this year (earliest realistic option ~Desert Solstice at year-end). May keep volume lower longer, race shorter distances (5K–marathon) for fun, and push a 100 toward next year depending on motivation.
Trusts intuition/urge for specific race goals to guide decisions.
Overall Outlook & Advice
Dodged a huge bullet by catching it early (before pelvic involvement or possible pulmonary embolism). Recovery has been relatively smooth given the potential severity.
Message: If something feels off and doesn’t match a normal running issue, get checked promptly, early action makes a big difference with clots.
Grateful for community stories shared after going public; open to questions via zachbitter.com or Instagram (@zachbitter).
Episode Transcript:
All right, everyone. Welcome back to another episode. For this one, I am going to do a review of everything that went into my blood clot, and everything I've learned since then about me personally with respect to the blood clot, things I learned about them in general, and what that looks like for me going forward with respect to training, racing, and all that sort of stuff.
So I have finally gotten to the end of the, the stage of doctor visits and blood work and everything that goes into trying to answer the how and why and what next type of stuff, and have got some clear direction as to what I can and can't do or need to do. So I'm gonna review that sort of stuff just to give everybody an update.
If you haven't been following along, I'll, I'll give a bit of a kinda recap on some of the early stage stuff that I did do a podcast about and have posted about on social media, and then kinda introduce some of the new stuff, too, in a little more detail, and then kinda what's next for me. So for the review, basically at the end of June, I was planning on doing a race in Milwaukee, Wisconsin, a hundred-miler at the Pettit Center, which is, in my opinion, one of the faster spots to chase a fast hundred-mile time.
And I flew out a couple days prior to the start of the race. I noticed that the first morning I was there, I went on a 45-- what was supposed to be a 45-minute easy shakeout run. My left calf started to progressively tighten up to the degree I didn't feel comfortable running on it. So, I cut that run short and immediately started thinking, "Okay, well, this race is probably not gonna happen."
I just know from prior experience, when you step on a starting line for a hundred-mile race, if you have something that's obviously a problem, it is gonna certainly become an issue. The hundred-mile distance has a-- does a great job of identifying your weakness and exposing it. So I was very non-optimistic about the reality of that race at that point in time.
But I had never really considered blood clotting as something that would be a potential issue for me, so my mind didn't go straight to that. My mind actually went to somehow maybe I picked up a minor calf strain. So I had a minor calf strain earlier in the training cycle, but I'd gotten through kind of the bulk of my speaking phase without it being any sort of an issue or concern during my training or recovery between sessions and things like that.
So it also wasn't something that was really on my mind as a potential risk. But once the discomfort went there, that's where my mind sort of went. After I officially dropped out of the race and a few days passed, I noticed that the symptoms were not really very consistent with any sort of muscle strain I had had in the past, and it basically was just this low-level throbbing that was constant, regardless of whether I was standing, sitting, walking, laying.
It was just always there, and that seemed to be something that was a little bit concerning. So at that point in time, I decided to go into urgent care and get an ultrasound. Went in there, they did the ultrasound, found a glo- blood clot that went from my ankle up to mid-thigh. And at that point, they just sent me straight to the urgent-- er, emergency room to figure out next steps, which basically were going to be one of two scenarios, which was if it's bad enough, they were gonna wanna keep me there, probably overnight, maybe more than one day, and actually go in and try to remove that clot.
If it was something where it wasn't progressing far enough or blocking enough of the blood flow getting to my lower extremities, they would put me on a blood thinner and send me on my way. So I had a little bit of a waiting period of a couple hours going through some of those labs, meeting with the doctors, having them review the ultrasound and determine what that was.
So thankfully for me the clot was big and long, but it did not progress to my pelvis, which is an im- important piece in terms of avoiding some much worse case scenarios, and it wasn't fully blocked. So for example they were able to pick up a clear pulse in my foot, which meant that that blood flow was getting past the clot down there.
So they weren't really worried at that point since at this point in time they're gonna put me on blood thinners, that it would become a problem beyond that. So I didn't have to stay in the emergency room any longer than that. They sent me a prescription for Eliquis, which is one of the better blood thinners on the market right now.
They wanted me to start out on a high dose, which was 10 milligrams in the morning, 10 milligrams in the, the evening, and then go back to Austin and visit with my regular doctor and then some specialists to try to answer some of the questions, do some testing to make sure there wasn't something serious or rule out anything that I should be exploring outside of just the fact that I had an active blood clot.
So I got back to Austin a couple days after that and pretty much got into the doctor right away. I think I was in the doctor within a couple of days, and they reviewed everything, and they basically wanted me to talk to a hematologist and a vascular surgeon. So the reason they wanted me to talk to a vascular surgeon was because if there were-- if there-- if the blood clot is not healing quickly enough, there is a potential that you could have some long-term or permanent vascular damage.
And since my hope is to return fully to running, training, and racing and lead an active lifestyle, I wanted to minimize the risk of vascular damage as much as possible. And that would be something that would require them to go in and take that blood clot out, despite not necessarily needing to do that.
So that's kind of my first big decision to make is do I have that surgery? Do I have that removal, or do I just stay on the blood thinners, follow the doctor's directions in terms of what I should and shouldn't do, and let it dissolve naturally? Because the way it usually works is once you're on the blood thinners, the clot's not gonna progress, and then you can just wait for your body to dissolve it.
I met with the hematologist after that, and basically, we went over the scenarios in which you would maybe wanna have it removed versus not removed. And based on my symptoms at that point in time, the hematologist told me that I'd be better off just staying on the blood thinners. And at this point, I was moved down to five milligrams in the morning and five milligrams in the afternoon.
So I got-- went from that kind of heavier dose to a more moderate dose of blood thinners and let it dissolve on its own. And the reason for that was because I had virtually no swelling left in the area at that point in time and zero discomfort. Both, both of those basically moved through pretty quick.
After about maybe a day or two on the blood thinners, I didn't feel any of that throbbing any longer. And then after about a week and a half, the swelling was almost entirely gone. So that sort of a scenario suggested that things were progressing at a fast enough rate where going and removing the clot wasn't gonna be necessary and that vascular damage was probably not something I had to worry about to the degree that I would need to go into a vascular surgeon and, and have that operation done.
So then it became the next step of just drawing out a timeline of what I can do. I can't run some labs to rule out other issues because sometimes clotting happens because of other things like certain cancers and stuff that you really wanna know about if you're, if you have. So we ran all those labs.
At that point, the, the doctor basically told me that I could do low-impact training like cycling, elliptical, hiking, and things like that, just no running, and wait till I was about four weeks out from the, from being on blood thinners to start any of the higher impact cardio stuff like running and that sort of stuff.
So that gave me a bit of a timeline to start building things around while I waited for some of the more detailed results, and I sort of began that process while I was waiting. And right about when I got to the point where I was cleared to start doing some runs was when my second meeting with the hematologist was up, and they had all the lab work back and things like that.
So I had a meeting with him, and he rolled out all the stuff they looked at. Thankfully, everything in my lab looked great. One thing they did find, though, is I tested positive for what they call a factor V Leiden gene, which is basically just a genetic mutation you inherit from one or both of your parents.
And if you have it, then your risk of blood clotting is at, at an increase of three to eight times. Three to eight times is a pretty big range, so really where you fall on that can depend on things like, was it one parent or both parents? Are you someone who is at risk with other things like different medications, lifestyle factors, and things like that, that would push you higher or lower on that range?
For me, really, the big thing is just lifestyle, where I'm not just running for health, I'm running for performance. So I get into these situations where I'm putting my body through a lot of stress, physical stress. You know, injuries are part of that sometimes. When you have an injury followed by lack of mobility, that's an increased risk factor for blood clotting.
Dehydration is a risk factor for blood clotting. Traveling and lack of mobility from that is an increase. So when you think about just the nature of racing an ultramarathon, you fly a lot of times to a location, you break your body down in, in one of the more ultimate ways you can, and then you are very immobile for a few days in a lot of cases, oftentimes dehydrated, and then sometimes you're getting on a flight and going back there.
So those are things I think going forward I have to really pay attention to because not only are all those risks, risk factors in general, but they can-- I have a higher risk in, with, with, with any of that stuff creating a- another clot in the future. So it was actually one of those things where once I sort of learned more about that, I started thinking back to the reality of how many ultramarathons I've done, and almost was something where I was like, "I'm kind of surprised it didn't happen at this point."
The, you know, the numbers are still low risk relative to not getting a blood clot. So if you look at it statistically, it shouldn't be a surprise I didn't have one yet. But I mean, I think of scenarios like where the factors, like the, the risk factors lined up about as amazingly as one could imagine, where, for example, in 2014, I did the World Hundred Kilometer Championships in Doha, and it-- since it's so humid and hot there, they started them at 6:00 p.m.
So we had this 100K race that started at 6:00 p.m. racing through most of the night, not sleeping at all after that. So you have one night, tons of body stress, no sleep, dehydration, and then that next day, that evening, I was getting on a flight to fly back to this, to the United States. So I basically had two nights of little to no sleep, tons of trauma, long flights, dehydration, all sorts of stuff.
And you just think of those scenarios, you're like, okay, well, that's where, that's where things would start compiling to the fact w- to the point where all of a sudden what would otherwise be a low-risk population starts to become maybe a little higher risk in those acute moments. But basically Well, what the hematologist told me, what that means for me is since everything seems to have been progressing really nicely with respect to the clot I had, I can basically return to normal activities and go about my lifestyle the same way as I did before.
I just need to be a little bit more mindful about risk factors when they are present. And really, what that means for me right now is I'll be on blood thinners for at least the rest of this year, that five milligram in the morning, five milligram in the evening of Eliquis through the end of this year.
And at that point, I'll meet with the hematologist again, and we'll review what the next steps are. We talked a little bit about that just with respect to what are some of the potential scenarios that could occur. And since I am higher risk, one of the options would be to just go on an even lower dose, just continuously of blood thinners just to keep that risk factor basically suppressed.
Another option would be since I do have a lifestyle that is in the mar- more macro sense protective of getting blood clots, but there are these acute situations around things like injury, lack of mobility, dehydration, post-race, and all that sort of stuff, flying, long travel and stuff like that, that it would be something where I would just use blood thinners proactively around scenarios when they occur that would increase my risk factor.
Some people have come off it altogether after that. That, what I would say at this point in time, would be probably the least likely scenario for me. I think I'm probably gonna be one of those, those two scenarios that I described before. I did ask the hematologist basically just "If you were me, and what would you think you would do?"
And he said that he would probably lean closer to just a really low level, low, low dose blood thinner more continuously just because you can plan as perfectly as you'd like, but it's never gonna be perfect in that scenario. So if you can mitigate that risk closer to entirely versus trying to predict, you're probably gonna have a lower risk of having another blood clot down the road.
For me, like at this point in time, I haven't really noticed any symptoms from the blood thinners. Obviously, being on blood thinners does increase your risk of other things. So, for example, if I fall and hit my head, things like internal bleeding and potential increased risk of problems from those sorts of things are higher when you're on blood thinners.
So I do need to be a little bit more careful around those high contact type situations, at least in the short term You know, the, I think blood thinners have gotten a lot better over the years with respect to how bad that risk is, so that's one of the reasons why I basically said, "Put me on the best one they have on the market right now," versus other options that were available that were maybe a little bit cheaper.
And but that's really the big thing that I have to maybe consider. Everything else has felt totally normal with respect to how my body feels. At this point, I've been running consistently for about three weeks, and really haven't noticed any difference with respect to having that blood clot there.
So... Or, or at this point it's, it's probably mostly dissolved, but I haven't noticed any sort of discomfort. It-- That was a bit of a transition, though. The first couple of runs I did, I could kind of feel like almost this really low-level cramping that needed to kind of loosen up for the first five, 10 minutes of a run.
But that basically just dwindled down to nothing after a few days, and at this point, i- if I hadn't, if I didn't know I had gotten a blood clot, I'd have no clue when I go out for a run. There's nothing that stands out as too different from that leg versus the other. There's really no additional swelling in there at this point.
So I think I'm in a pretty good place with respect to getting through that side of things, and now it's just about making sure I do the things that I need to do to make sure I don't get another one in the future since I am at higher risk. The only-- The o- the other interesting thing from this timeline that's just maybe an interesting thing to share is once I got the blood clot I do track things like overnight HRV, resting heart rate, and that sort of stuff.
And I had... My HRV just plummeted after I got the blood clot, and I kept monitoring that along the way, and it just sort of stayed low for maybe the first week, week and a half, and then it kinda gradually started climbing back up. But it took probably close to five, six weeks before I kinda-- that line pushed back into the green zone of the range that I'm normally in and has just recently kind of reached that middle part of that.
So, that is just, I think, mostly a byproduct of my body actively trying to heal that blood clot, and that was showing up in some of that data. Same thing with the resting heart rate. That kinda came up for a bit there. I had a few weeks where my resting heart rate was about 10 beats per minute higher than it normally would be.
That's mostly normalized at this point too. So those are maybe a little bit more symptoms or timelines that I don't know if I would have noticed it necessarily had I not been tracking that, but they were there. They were in the data. So there is a little bit of a recovery phase as your body's working through those early stages of dissolving that clot.
At least that's how it showed up for me. In terms of next steps, really the way I'm looking at it is my time off of training really wasn't that grand. It was about four weeks off from running, two weeks off of training altogether. So I had that kind of bridge for two weeks with the cross-training there.
And now that I'm cleared to basically do what I can tolerate, I need to be mindful of building back up gradually enough, 'cause, you know, 30 days off from running, I probably didn't lose a tremendous amount of fitness, but just the lack of impact there, if you just start going back to 100% right away, it's just a s- a recipe for injury.
So I'm being a little bit more cautious with things like volume and the amount of volume spent at harder sessions and things like that. But even without the blood clot, since I did a full training for a hundred-mile race, usually after something like that, I'm looking at a couple weeks where I'm doing little to no structure work and then a few weeks where I'm kinda gradually building back up.
And then usually my next step is to introduce some training at a lower volume that helps with things like speed reserve. So That's usually at its lowest at that point in the, in the training cycle because I'm coming off a phase of training where I was focusing a lot on volume, a lot on low intensity long run stuff, and not doing nearly as much of the, the short intervals or sprints or s- things like that.
So in most cases, that is probably my biggest pinch point, and since it's a very unspecific training, training session- compared to the pacing and the intensity that I would do for a goal race, like 100 miles, it's usually the next step. So that's sort of where I've been at now. I've been doing some really short, kind of almost 95 to 100% type sprint sessions.
I've gotten a couple short interval sessions, albeit at a very low volume relative to what I would normally do, and just trying to maybe-- or trying to get my paces back to where I like to see those for, in the short term. And that's basically what I would do regardless if I were to s- say start the process to train for something like a 100 mile race.
I haven't decided whether I'm gonna do another 100 miler or not in the short term, and by short term, I mean this year. So I would say the earliest I would probably consider doing 100 miler would be at the end of the year around Desert Solstice, would be a, a, a clear, obvious option that would probably fit a good timeline for me with respect to where things are at right now.
But I'm gonna wait another few weeks or maybe even a couple months before deciding that because even after I get through this next few weeks of working on things like speed reserve and short interval, v- interval work
I may just keep volume a little bit lower and continue to work on running efficiency a little longer than I normally would before pivoting to a peak. And if that means spending the rest of the year doing this, maybe jumping in some shorter races just for fun, like 5K, 10K, half marathon, marathon type stuff, I might kind of play around with some of that stuff for a bit and then wait until next year to do a 100-miler.
But we'll see where my desires and interests go. I do think one of the things that I have followed through my entire running career is that if you f- if you get the urge to train for a specific type of race, that can be very powerful. So I do really trust my intuition as I get into training with respect to what is it that I'm really looking forward to doing, what is going to be exciting and motivating enough that when I have a session where I have to work a little bit harder or where it's not as fun as maybe just going out for a, for a low s- low structured easy run or something like that, I'm willing to do it, and that usually guides me a lot of times with respect to picking a race.
So I'm gonna give myself a little bit more time to get to that. But that's basically all I got with respect to the overview of everything. I'm really excited to be through that, and honestly, I think I dodged a huge bullet. It's just one of those things where had I waited and that clot had progressed up into my pelvis, or if I had ignored it and kept running or done the race and dislodged it and ended up having it end up in my lungs and get a pulmonary embolism or something like that, I'd be looking at a much, much more difficult timeline that would potentially be just a lot more problematic.
So obviously, I would rather not have gotten the blood clot, and I would rather not be-- have the Factor V Leiden gene. But since it happened, I think it's progressed in about as quick and seamless a way as I could imagine given the s- the potential severity of something like this. So I'm excited to kinda get back to some, some normal stuff and, and continue to train and run and things like that.
And yeah, if you have any questions or stories you wanna share, I'm-- it, it's been really interesting to hear people's stories. I've-- You know, since I've been very public about this, I've had probably, at this point, hundreds of people that have shared stories about when they've gotten blood clots and what happened in their pro- process and things like that.
So it's been interesting to hear from the broader running world with respect to some of that stuff and, and pretty like gratefulness inducing, I would say, given some of the stories I've heard. I, I guess if I have a, like a message to people listening to this out there, it's if you feel like something is off that is not presenting like a normal run, acting fast with blood clots is definitely gonna make things a lot more smooth if you catch it early.
Thankfully, I was able to do that, so we're gonna be back into the normal swing of things here sooner rather than later. But other than that, that's what I got for this one. If you want to reach out to me, you can head over to my website at zachbitter.com or shoot me a note on social media. My Instagram account is probably the one I check the most frequently, which is just @zachbitter