A fellow cyclist described to me a health episode involving a blood clot.
In a nutshell, he had gone for a ride and come home and then suffered through two days of intense pain in his chest/back area. Heading to urgent care when it became intense, it turned out to be a blood clot lodged in the lung, likely formed and then dislodged from a large vein in the lower body (perhaps hip area).
Clots that form in the lower body in veins travel upwards with the blood to be oxygenated and this is why they lodge in the lungs (barring a congenital heart defect). So there is little chance of such a type of clot reaching the brain; those types of strokes are caused by other factors. It is thought that small clots (1-2mm) in the lungs are fairly common, and that the body assimilates them.
Aspirin and clotting: dual edged-sword
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Being of similar age, the foregoing piqued my interest: as aging athletes, what might be the role of aspirin? Aspirin has anti-clotting properties, which is a dual-edged sword. Low-dose aspirin is used by many as a prophylactic.
Another speculative point is that highly trained aging athletes might be susceptible to blood clots while sleeping and similar because of a very low resting heart rate (venous “flushing”, my own made-up term to articulate the idea). I am researching this point.
When, how much and whether to take? (see updated notes that follow)
- If aspirin is to be taken at all, it seems to make the most sense to take it after the effort, so as to have maximum anti-clotting effect were a clot imminent (from the effort), and yet the aspirin would have mostly dissipated prior to the next-day ride. How much to take?
- Taking aspirin before or during a ride could be risky: if a crash were to result in a bleeding cut or laceration, aspirin could cause excessive and perhaps even dangerous bleeding.
- If a crash results in no external bleeding but does result in impact, might immediately consuming aspirin be called for (how much?), so as to minimize the risk of a blood clot from the trauma? But this too could be risky, due to the risk of internal bleeding, say in a badly bruised area. The situation here is not at all clear-cut.
The above is speculative thinking and not advice—check with your own doctor. Hard and fast answers might prove elusive, but it’s worth pondering.
UPDATE after talking to a heart surgeon
I spoke with a heart surgeon with 35 years experience (these guys have to know clotting). What follows is my rendition of what I learned.
Aspirin works by “poisoning” the clotting receptors on platelets (drugs such as coumadin work by blocking the chemical chain for clotting, very different and much more dangerous if bleeding starts). Aspirin is thus a permanent change to platelets, regardless of when taken. But toxic doses of aspirin would have to be consumed in order to inactivate all the platelets (think 'moles' in the chemistry sense).
New platelets are constantly being created by the body; this is why surgeons ask patients to be off aspirin for a 7-10 days prior to surgery—to let the body release new platelets not previously inactivated by aspirin. Finally, about 20% of the population is non-responsive to aspirin in its platelet clotting factor inactivation (but still respond to analgesic effects).
Bottom line: barring a medical issue (bleeding gastric ulcers, sickle cell, surgery, etc—see your doctor), aspirin taken daily may be helpful and is unlikely to be harmful. And it won’t matter when taken—once platelets are inactivated, they stay that way in terms of clotting ability.
- Dehydration can be a factor in clotting; stay hydrated.
- Fixed body positions, particularly those that stress the body can cause clots (e.g. those viciously small airline seats). Such as sitting on one’s folded leg, which appears to have been the precipitating cause of the clot in the fellow cyclist narrative that starts this post (clot was in femoral vain in knee area according to an ultrasound, sat on leg folded for several hours, thus crimping the femoral vein for a long period).
The article on using aspirin to prevent a Deep Vein Thrombosis (DVT, AKA clot in the leg/lower extremity), or the likelihood of a Pulmonary Embolism (PE) was interesting to me. I had my first DVT and PE almost 10 years ago… I’ve had two DVTs. The first, I dismissed as a calf strain that wouldn’t go away. Ignoring it lead to a PE developing. The second DVT felt like sandpaper inside my calf… I’ve been to a hematologist twice, there’s no reason (based on current testing) for why I have a predisposition.
Not a doctor either but my recommendation is to pay attention to pain in the lower leg, rather than preventative medication that might mask an issue. If it feels different than a strain, or hasn’t left after 3 days – it’s worth pursuing an ultrasound to confirm that things are OK. People can develop thrombosis (clot in a vein) due to blood “pooling” from inactivity, and location of the clot distinguishes classification of being a DVT or not. Another preventative measure is to walk for 5 minutes every hour, especially if sedentary (IE work at a desk, traveling). Compression socks are a good idea too – medical grade is available but typically requires a doctors note/prescription. Some people have given me grief on group [cycling] rides because compression socks are en vogue, though the value depends on the amount of compression.
I haven’t encountered any issues cycling while on blood thinner (warfarin/Coumadin), but have bled into my lungs in the swim portion of a sprint triathlon. The alveoli is where oxygen transfers into the blood stream, and it is common for people to bleed a little in times of stressful breathing. My clotting factor has to be less than normal peoples’, so it stands to reason that what would have sealed without issue did not occur. I still swim, haven’t had an issue since but I also mind & manage my stress more now when swimming.