Blood Clots: When a Pain in the Leg is More than a Tight Muscle

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My upper right calf was ground zero for my blood clot. You may notice the veins in that calf are more prominent than the other. Permanent evidence of my clotting episode.

On April 15, 2004, just six months after I quit my full-time biotech job in Boston and moved to Michigan to join the Hanson’s-Brooks team, I experienced a pain in my calf. At first it seemed like one of those normal runner things, especially since just ten days before I had run the 2004 Olympic Trials Marathon. But as it turned out, this was serious.

You might be surprised to learn that deep vein thrombosis (DVT) and pulmonary emboli (PEs) are relatively common among distance runners, especially women, but it’s absolutely true. In fact, I’m not even the only one on the Salty team to have experience with them! Despite how common they are, there still isn’t a lot of information about the phenomenon.

Having just passed my 12th anniversary of my DVT and subsequent PEs, I wanted to share what it felt like to have a blood clot, what every woman runner needs to know about them, and what to expect should you ever have one.

DVT, PEs, and Blood Clots

Before we go any further, a few definitions are necessary. Blood clots are areas of thickened blood, like the scab that forms over a cut to stop the bleeding; that’s an example of a good blood clot. A deep vein thrombosis (DVT) is a clot that forms in a deep vein, often in the calf. These are relatively harmless on their own, but having one is a dangerous condition because the clot, or parts of it, can travel through the blood stream and enter your lungs, where it can block a blood vessel in the lung and become a pulmonary embolism (PE). PEs can be fatal.

My Story

In 2004, I was completely in the dark about blood clots, so when I woke up with calf tightness that morning I thought nothing of it. I had a spot of tightness in my calf that varied anywhere from mildly annoying to painfully tender. I remember trying to roll out my calf to alleviate the tightness, but couldn’t do more than lay the massage stick against my leg because any amount of pressure on my calf made me want to vomit. This should’ve immediately been a sign that something was wrong, but I brushed it aside for an entire week.

A few days after the calf pain started, I began to notice difficulty breathing, especially when running. At my coach’s recommendation I had taken two weeks off of running after the Trials, so I initially attributed the shortness of breath to being out of shape. But over the next few days my breathing became worse; I was getting winded walking up two flights of stairs. The final straw came when I joined a community run and got dropped by everyone. I felt like I was running all out with how badly I was breathing, but was going two minutes per mile slower than my usual easy pace. I stopped right there, walked back to my car, and called the doctor.

Two days later, I was in the ER getting an ultrasound on my leg and a CT scan of my lungs. I was admitted for a DVT in my right calf and several small embolisms on the periphery of both lungs. I spent five days in the hospital hooked up to an IV of blood thinners.

How does a young, healthy runner end up with deep vein thrombosis?

Initially, the doctors were very confused about how I ended up with a DVT. I was in my 20s, active, didn’t smoke, wasn’t pregnant, hadn’t had any correlating injuries, surgeries or health conditions, and hadn’t traveled anywhere very far. And when I first checked with my parents, there was no known family history of blood clots.

Upon closer review of my circumstance, a few things stood out as possible risk factors. A week and half before I woke up with a sore calf, I ran the first 18 miles of the Marathon Trials. During the race I had stomach problems and felt extremely lightheaded. I stopped at 18 because for the first time ever it felt like if I pushed through I’d end up in the hospital. The day after the race I flew from St. Louis to Detroit and then several days later from Detroit to Pennsylvania. Neither flight was particularly long, maybe two hours tops.

Another possible risk factor was that I had been taking hormonal birth control to help regulate my cycle. On top of that, when I first felt the clot in my right calf, I thought it was residual tightness from my ill-fated marathon a week and a half before. Over the next week I had two massages done on that calf, which in turn caused small pieces of the clot to break off and travel to my lungs. Lastly, when I finally got results from the blood work done in the hospital, I found out I have a genetic factor that predisposes me to clotting called Factor V Leiden Mutation.

The Factor V Leiden was not in itself a huge cause for concern because I only have one copy of the gene mutation, which makes my risk only slightly higher than normal, whereas someone who inherits two copies of the mutation, one from each parent, is at a significantly higher risk.

So, what ended up causing my clot was a perfect storm:

  1. Dehydration from running most of a marathon
  2. Two flights
  3. Hormonal birth control
  4. A genetic predisposition to blood clots

Female Distance Runners and Blood Clots: What YOU Need to Know

Over the twelve years since my clotting episode, I have met several other female distance runners who have experienced blood clotting episodes. Of the eight women runners I know personally (including myself) who have had clotting episodes, all but one were on birth control at the time of their clots, several have genetic predispositions, several developed their clots after a hard workout or race, and several had sustained a lower leg injury in the weeks or months prior to developing their clots.

In 2013, Claire Hull, PhD and Julia Harris, MD published a paper that demonstrated that certain aspects of being a runner may heighten the risk of developing a blood clot, as shown in the Triad of Risk Factors for venous thromboembolism, shown below in Figure 1. Especially if you are on any kind of hormone therapy (like birth control) or have one or more genetic predispositions to developing a clot, the strain of long distance running, especially in the case of injury, can contribute to the development of a blood clot. Bear in mind that this in no way means you will get a blood clot from running, just that it’s important to be aware of the symptoms (Figure 2).

Screenshot 2016-05-09 at 4.44.45 PM
Figure 1: This diagram, the Triad of Risk Factors for venous thromboembolism, was created by Rudolph Virchow, a highly regarded physician in the late 19th century. It shows how certain risk factors come together to cause clots. The authors highlight which of those aspects can pertain specifically to runner (red). Reprinted with permission from “Venous Thromboembolism and Marathon Athletes,” Hull and Harris 2013.

Figure 2: Signs and Symptoms for VTE (adapted with permission from “Venous Thromboembolism and Marathon Athletes,” Hull and Harris 2013.)

  • Deep vein thrombosis
    • Swelling, usually in one leg, often visible in the calf and ankle
    • Leg pain or tenderness or the sensation of chronic cramping that does not ease with ice, stretching, or painkillers; inactivity may exacerbate pain and activity may alleviate pain
    • Reddish or blue skin discoloration (often obvious when bathing with hot water)
    • Leg feels warm to the touch
    • Unexplained upper arm or neck swelling (upper extremity deep vein thrombosis)
  • Pulmonary embolism
    • Swelling, usually in one leg, often visible in the calf and ankle
    • Sudden shortness of breath or breathlessness on exertion
    • Rapid heart rate
    • Cramp in side or chest, painful breathing
    • Chest pain radiating to the shoulder
    • Fever
    • Unexplained cough, sometimes with bloody mucus
    • Feeling lightheaded and dizzy or fainting

What to Expect As a Runner After A Blood Clot: Treatment, Recovery and Returning to Action

Thanks to being repeatedly told during my hospital stay that I was lucky I didn’t die, many scary things went through my mind in the months afterward. Anything I felt physically, at least for the next few years, made me panic and feel that my body was falling apart again. The reality wasn’t nearly so bad, but it definitely wasn’t a cakewalk either.

Treatment and Side Effects

My initial treatment involved an IV drip of Coumadin, a blood thinner. I also did not run for six weeks. Long-term I was on oral Coumadin for about a year and a half, until I had gone over a year with no further clots. As I returned to training and added back miles, I kept failing the Prothrombin Time/International Normalized Ratio test, which measures the level of a clotting agent in your blood (oversimplified). It took several months before my blood finally stabilized and I was able to level off the dosage.

As a runner on blood thinners I experienced some side effects. In the first few months, I often got the feeling of pins and needles in my limbs. It woke me up in the middle of the night and freaked me out. I also felt an increased sensitivity to cold, as if the Coumadin triggered Reynaud’s. It was a huge annoyance, especially in the winter, with long runs in temperatures below freezing. On the flip side, I handled heat better, which was nice. While I did not have any issues with increased bruising, which can be a side effect, I did have one instance of excessive bleeding after I nicked myself shaving and the cut didn’t stop bleeding until 24 hours later. All these side effects went away over time, either while I was on Coumadin or once I stopped.

Return to Running

Before I could be cleared to return to exercise, my pulmonologist wanted to do a stress test. I had the test done a month after my initial diagnosis. When the results looked ok I received the all-clear to start back with some low-impact exercise. I did a lot of swimming and light pool running for two weeks. Six weeks after my hospitalization I started running again. That first run felt awesome, particularly when compared to my last run before the diagnosis!

From there I slowly added runs back in. The first week I ran every other day, and from there I think I added about ten miles a week until I got to 70 miles somewhere in the middle of the summer. This approach worked well for me.

I had one minor setback in late summer when I had soreness in my calf that felt like the same sort of pain the clot produced. I had a follow-up ultrasound and fortunately it was not a clot, only discomfort that was likely due to a stretch of hot and humid weather that caused some swelling in the veins affected by the clot. In the hospital the doctors had warned me that calf pain could limit my return to running; thankfully, this was the lone occurrence of such pain.

By six months post-clot I was back to my previous fitness, if not better. I set two 10k PRs and a half marathon PR by the end of the calendar year. By one year after the clot, I ran a marathon PR at Boston.

The Silver Lining

My blood clot caused me to become more cautious about my training and to adopt more of a “listen to your body” attitude, which I believe is to thank for getting me back to running competitively and faster than ever. I got really in tune with my body and wasn’t afraid to back off and take it easy when I needed to. This allowed me to successfully complete workouts and race well. Because I was still in a group training environment this wasn’t easy to do; I’d often just have to let the group go and run by myself on my easy days. But since it was yielding success in workouts and races, I stuck with it.

Long Term Treatment and Considerations

Baby, I was not born this way.
Compression socks are an excellent preventative strategy!

Compression Socks – I have been fortunate in that I have not had a recurrence of blood clots since the one twelve years ago. I also started wearing compression socks whenever I had long bouts of travel, be it by airplane or car, and whenever I’d be on my feet for extended periods of time. I wear compression socks at work since it keeps me on my feet for several hours at a time. I still feel like every once in a while my right calf swells if I’m standing or sitting immobile too long, so wearing the socks helps for peace of mind.

Pregnancy – In the aftermath of the clot I was told that if and when I were to get pregnant I’d have to take daily injections of Lovenox throughout my pregnancy, and for 6-10 weeks postpartum, as the postpartum period is prime time for risk. For both of my pregnancies, I did daily injections of Lovenox for the first 36 weeks, then switched to heparin for the final weeks until delivery because clearance of heparin is faster than Lovenox and makes for less complications if you need an epidural during delivery.

Future Complications and Further Research

Even though I have gone twelve years without another clotting episode, having the genetic predisposition of Factor V Leiden mutation means that I am at a higher risk of developing a clot than someone who does not have a genetic factor. Therefore, it is in my best interest to eliminate or control any risk factors that will compound the likelihood of developing a clot, such as avoiding hormone therapy, long air travel, and smoking (clearly not a problem).

I found that educating myself went a long way in knowing what to expect with treatment and long-term issues. As many runners have learned, you are your own best advocate and being educated about your condition, especially when it relates to and involves your athletic passion,  is extremely helpful when working with doctors to ensure your overall health and well-being. While doctors over the years have warned me of the above mentioned risk factors, I have also done a lot of research on my own, digging up journal articles on the topic.

  • One of the most comprehensive resources is, a website by the National Blood Clot Alliance. Their page specifically for athletes is located here.
  • There is also The Clot Buster blog, highlighting athletes who have suffered from clotting episodes and their recovery afterwards. It even includes an interview with Oregano!
  • Special thanks are owed for this article to Claire Hull and Julia Harris for allowing us to publish the tables and the triad from their paper, “Venous Thromboembolism and Marathon Athletes.” Their work is definitely worth a read!


If you are ever in the unfortunate situation where you develop a blood clot, I highly recommend seeking out others who have had similar experiences and using the resources that are out there. Being educated on your condition goes a long way in the recovery process!

Have you experienced a blood clot, or do you know someone who has?

I'm a licensed massage therapist with a background in biochemistry and also a mother of two. After almost two years of focusing on shorter race distances, I am back on the marathon training horse. My next goal race is the Bank of America Chicago Marathon. I write mostly about health and science as they relate to running as well as being part of a running family.

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  1. I am so happy that you wrote this! It’s a huge topic to tackle in one post and really important for people to know about. I definitely thought my PE was a pulled muscle for way longer than I should have, but it was extra confusing because my clots didn’t originate in my legs and I had no risk factors at all (as far as anyone has been able to tell). It’s so good to have information out there for people who are in the middle of this and feeling discouraged and unsure if they’ll ever be competitive again.

    1. I’m glad I had the opportunity to share my experience and what I’ve learned over the years. It’s really interesting as I’ve met quite a few people now who had clotting episodes with no genetic risk factors. Makes you wonder if there are other factors out there that just haven’t been figured out yet by scientists. I know that the one I have wasn’t discovered until 1994. So when I first started doing research on it, there was only 10 years worth of data, which really in the grand scheme of science is not a lot.

      You also bring up a good point about the mental component of going through something like this. Being told you might not run again, when you’ve run for most of your life, is quite a shock. It’s hard to wrap your head around having to stop something that is such a part of you and that you enjoy. Most runners tend to be stubborn and resilient, so I think they have a better chance of coming back from something like this, provided they really do listen to their bodies and pay attention to any further warning signs.

  2. Thanks for the very thorough post. We need to educate our fellow runners who are not aware of the dangers. I’m glad to hear you are taking the appropriate precautions to prevent recurrences. I’ve had similar experiences (I have the Factor V Leiden mutation also), and fortunately I have been able to come back from a couple of cycles of DVTs and PEs.

    1. Sorry to hear you have gone through this multiple times, but I’m glad to hear you have been able to come back from them. It’s a very fascinating topic to me and very interesting that quite a few runners have had similar experiences.

      I think being aware of the risk factors and the symptoms are key when dealing with this stuff. Obviously, you don’t want to spook anyone, but being aware of the tiny possibility of it happening is better than being completely in the dark about it.

  3. Thank you! I consider myself pretty knowledgable and hadn’t heard of this. As I was reading, I wondered about handling pregnancy and you covered that too! Love the cites as well. I don’t know if I have any factors but I got in the habit of using compression socks on flights after too many redeyes and constantly getting “pins & needles” in my legs. I just carried it over to all air travel. My mother has terrible varicose veins and I’m doing what I can to prevent them so I wear compression more generally. Hoping that episode is the last for you.

  4. HI!!!!

    I would love to touch base with you. I was diagnosed 11/30/16 and am trying to learn and read all about this! I will provide my contact info down below.
    I did an Ironman with two blood clots and I know now I carry the gene! My best and hope to touch base SOON!

    1. Hi Mary! Thanks for reaching out. I will send you a direct message via the email address in the next couple of days. I hope you are are recovering well.

  5. I can not thank you enough for this! I am a very healthy 51 year-old woman. I’ve been running daily for the past 6 years (after a hiatus of a decade, unfortunately). It is a huge part of my identity and mental health practice. Two days ago they found a clot in my pelvis, and I’ve been having a lot of trouble finding happy-ending stories. At the moment, I can barely walk to the bathroom, but I feel can make a plan now, and can hope to get back to myself and my daily routines eventually.

    1. So sorry to hear about your clotting episode. I’m glad this post could be of some help. Feel free to shoot me an email if you have any follow-up questions as you get back into a regular running routine. Best of luck!

  6. I was diagnosed with a bilateral PE and DVT this past October, only 6 days before I was supposed to run the Chicago marathon. I was also on hormonal birth control, and they believe that caused the clots. I had the same episode where I was running so much slower than my normal easy pace but I was so winded that it felt like I was racing. I went to Urgent Care and they urged me to go to the ER to be tested for blood clots. Thank goodness I listened to my body!

  7. Thank you so much for writing this article! I experienced a very similar “perfect storm” as you. I ran a marathon on 10/1/17, flew two weeks later and then one week later was diagnosed with bilateral pulmonary embolisms. I was on hormonal birth control at the time, too, but was diagnosed with Protein C deficiency. Interestingly, I have a friend who also developed PEs after running the same marathon – crazy, right? I am so happy to hear about your successful recovery! Thank you for spreading this information and positive story!

  8. Thank you for the article, I’m so glad that you recovered and haven’t had any recurrent issues. My sister (while on hormonal birth control) had a blood clot and was diagnosed with Factor V Leiden. I got tested and found out today that I also have Factor V. Luckily, I went off of birth control prior to becoming a runner and have not had any issues. I’m thankful that I know my diagnosis so I can be careful about wearing my compression socks (especially while driving from Michigan to Boston this April) and also so I know not to go on any hormone therapy during menopause.