Why Athletes Consider Low-Dose Aspirin
Low-dose aspirin is one of the most widely used drugs in America, and some athletes take it hoping to protect their heart during intense training or long races. Guidelines have shifted considerably in recent years. Our editorial team reviews what aspirin does, who benefits and why self-prescribing is risky.
How Low-Dose Aspirin Works
Aspirin, or acetylsalicylic acid, irreversibly inhibits the cyclooxygenase enzymes COX-1 and COX-2. At low doses, typically 81 milligrams a day in the United States, its main effect is blocking COX-1 in platelets, which reduces production of thromboxane A2 and makes platelets less sticky.
Because platelets cannot make new enzyme, the effect lasts for the platelet's lifespan of about 7 to 10 days. This is why even small daily doses have a sustained antiplatelet action.
At higher doses, aspirin also relieves pain, fever and inflammation, functioning like other nonsteroidal anti-inflammatory drugs (NSAIDs). Those analgesic doses are much larger than the cardioprotective dose.
Aspirin is available over the counter in the US. It is not on the WADA prohibited list, so its use is not an anti-doping issue. The question is medical, not regulatory.
What the Guidelines Say Now
For people who already have cardiovascular disease, such as a prior heart attack or stroke, low-dose aspirin for secondary prevention is well established. The Antithrombotic Trialists' Collaboration showed clear reductions in vascular events in this group.
Primary prevention, meaning use by people without known heart disease, is different. The ASPREE trial in healthy older adults found no cardiovascular benefit and more major bleeding with aspirin.
In 2022, the US Preventive Services Task Force recommended against starting aspirin for primary prevention in adults 60 and older, and said that for adults 40 to 59 with elevated cardiovascular risk the decision should be individual, as the net benefit is small. The 2019 ACC/AHA guideline similarly limits routine use.
| Group | Current US guidance (summary) | Main concern |
|---|---|---|
| Known heart disease or stroke | Generally recommended, as prescribed | Bleeding risk monitored by physician |
| Adults 40–59, higher CVD risk | Individual decision with clinician | Small net benefit |
| Adults 60+, no CVD | Do not start for primary prevention | Bleeding outweighs benefit |
| Young healthy athletes | No routine indication | Risk without benefit |
| Children and teens with viral illness | Avoid | Reye's syndrome |
Aspirin in Sport: Common Reasons and Their Problems
Some endurance athletes take aspirin before marathons or triathlons, believing it prevents heart attacks during exertion. There is no good evidence supporting this practice in healthy athletes, and the bleeding risk remains.
Others use higher doses for muscle soreness and minor injuries. Research on NSAIDs in training, reviewed by Lundberg and Howatson, suggests that regular high-dose use may blunt some adaptations to resistance training, although findings vary and low-dose aspirin has been studied less.
Trappe and colleagues found that over-the-counter doses of ibuprofen and acetaminophen suppressed the post-exercise rise in muscle protein synthesis. Whether aspirin has a similar effect at analgesic doses is less clear, but the possibility is a reason to avoid routine prophylactic use.
Warden's review on prophylactic NSAID use in athletes concluded that risks, including gastrointestinal and kidney effects, generally outweigh benefits when these drugs are taken before exercise to prevent pain.
Risks Athletes Should Understand
- Gastrointestinal bleeding and ulcers, increased by endurance exercise-related gut stress
- Easier bruising and prolonged bleeding after contact injuries
- Higher risk of hemorrhagic stroke in some populations
- Worsening of asthma in aspirin-sensitive individuals
- Kidney stress when combined with dehydration in long events
- Interactions with anticoagulants, other NSAIDs, SSRIs and some supplements such as high-dose fish oil
Contact and collision sports add a specific concern: an athlete on antiplatelet therapy who suffers a head injury may bleed more. Team physicians generally want to know about any aspirin use.
When Aspirin Makes Sense for an Athlete
Masters athletes with established coronary disease, prior stents or other conditions for which a cardiologist prescribes aspirin should continue it. In this situation, the drug is part of medical treatment, not a performance aid.
For a healthy recreational athlete in their 40s or 50s with risk factors such as diabetes or a strong family history, a physician may calculate cardiovascular risk and discuss whether aspirin is worthwhile.
For young, healthy athletes, the priority should be screening. Pre-participation evaluations, family history and, where appropriate, ECG screening are far more relevant than taking aspirin.
Anyone experiencing chest pain, unusual shortness of breath, palpitations or fainting during exercise should stop training and seek medical evaluation immediately, regardless of aspirin use.
Editorial Team Conclusions
Low-dose aspirin is a valuable drug for people with established cardiovascular disease, but it is not a general shield for athletes.
Current US guidance discourages starting it for primary prevention in older adults and calls for individual decisions in middle age.
Routine prophylactic use before races or to manage soreness carries bleeding and gastrointestinal risks and may interfere with training adaptations.
For further reading, see our articles on cardiac screening for athletes, NSAIDs and muscle growth, and recovery strategies without painkillers.
References
- Davidson KW, Barry MJ, Mangione CM, et al. Aspirin use to prevent cardiovascular disease: US Preventive Services Task Force recommendation statement. JAMA. 2022;327(16):1577–1584.
- McNeil JJ, Wolfe R, Woods RL, et al. Effect of aspirin on cardiovascular events and bleeding in the healthy elderly. N Engl J Med. 2018;379(16):1509–1518.
- Antithrombotic Trialists' (ATT) Collaboration. Aspirin in the primary and secondary prevention of vascular disease: collaborative meta-analysis of individual participant data from randomised trials. Lancet. 2009;373(9678):1849–1860.
- Arnett DK, Blumenthal RS, Albert MA, et al. 2019 ACC/AHA guideline on the primary prevention of cardiovascular disease. Circulation. 2019;140(11):e596–e646.
- Trappe TA, White F, Lambert CP, et al. Effect of ibuprofen and acetaminophen on postexercise muscle protein synthesis. Am J Physiol Endocrinol Metab. 2002;282(3):E551–E556.
- Lundberg TR, Howatson G. Analgesic and anti-inflammatory drugs in sports: implications for exercise performance and training adaptations. Scand J Med Sci Sports. 2018;28(11):2252–2262.
- Warden SJ. Prophylactic use of NSAIDs by athletes: a risk/benefit assessment. Phys Sportsmed. 2010;38(1):132–138.
