Anti-inflammatory Interventions in Sports: A Critical Update

The original article was published for the RunTriMag on August 26th, 2024. Access here: https://runtrimag.com/anti-inflammatory-interventions-in-sports-a-critical-update/

This month, I want to discuss the use of anti-inflammatory interventions in sports, a topic I frequently encounter. It’s evident that our understanding needs an update from previous beliefs.

For many years, my research focused on harnessing inflammation to regenerate brain and spinal cord lesions, aiming to find new treatments for degenerative conditions like Alzheimer’s disease and Multiple Sclerosis. But wait… is this a Neuroscience lecture? Let me explain: many bodily mechanisms are similar, including inflammation, and muscles aren’t much different from the brain in this regard.

Here’s something you might not know: inflammation is NOT inherently bad. Inflammation is a NATURAL response required to promote repair. When we exercise and break muscle fibres, inflammation is the process that enables muscles to grow. During this process, damaged tissues send signals perceived by our immune cells. These immune cells are crucial for regeneration—without inflammation, repair can’t happen. They remove debris from damaged tissues, allowing the tissue to be reshaped and repaired. Moreover, these cells send signals once the debris is cleared, attracting satellite cells (muscle cell progenitors) to the injured area to differentiate into new muscle cells [1].

Anti-inflammatories Delay Repair

The old thinking was that we needed to stop inflammation because it was responsible for pain. While it’s true that immune cells release cytokines such as prostaglandins that cause pain, pain itself is not a bad thing. Pain limits movement when the body needs time to repair. Acute pain indicates that the injury is significant and requires time for healing. Once inflammation and pain levels decrease, you can move again, which is essential for the new tissue to form correctly. This is why rehabilitation is so important to ensure that new tissue fibres get positioned in a functional way.

So, what about the anti-inflammatory treatments that everyone uses and that make us feel better? Let’s dig into what science has shown so far. We all know about NSAIDs (Non-Steroidal Anti-Inflammatory Drugs), such as ibuprofen (Advil), naproxen (Aleve), and diclofenac (Voltron). Aspirin is sometimes considered an NSAID, whereas acetaminophen (paracetamol) is not. NSAIDs work by inhibiting cyclooxygenase (COX) enzymes, specifically COX-1 and COX-2. These enzymes are crucial for converting arachidonic acid to prostaglandins. By blocking COX enzymes, NSAIDs reduce the production of prostaglandins, decreasing inflammation and pain.

However, prostaglandins are required for muscle regeneration [2], and NSAIDs could interfere with this process, slowing down recovery from exercise-induced muscle damage, limiting gains in strength [3]. Studies have shown that the inhibition of prostaglandins negatively affects tissue healing at the cellular levels, though this is not always observed at the structural level [3, 4]. The effects of NSAIDs on muscle growth may also be dose-dependent, with higher doses having more detrimental effects than lower ones [5]. What about the use of ice? Ice primarily provides an analgesic effect, reducing pain, but studies in rodents have shown that it also decreases blood flow to the injured area and key immune cell infiltration, which may delay the regenerative process [6, 7]. However, more research is needed on the use of ice in humans to fully elucidate its effects on muscle recovery [8]. 

Anti-inflammatories during competition

A critical issue is the use of NSAIDs in competitions, such as marathons and ultramarathons. Studies have shown that NSAIDs do NOT improve performance and are ineffective as ergogenic aids [9]. In fact, NSAIDs can pose health risks, which are exacerbated under the high stress of such events. Taking NSAIDs during long races won’t just fail to help; it can increase serious health risks. NSAIDs can cause disturbances in electrolyte balance, leading to hyponatremia (low sodium) [10]. They can also affect renal function by reducing blood flow to the kidneys, potentially causing kidney damage or exacerbating pre-existing kidney conditions [10]. This is due to the decrease in prostaglandins, which regulate blood flow and kidney function [10]. In the case of ultraraces, where dehydration is already a concern, this can result in serious problems. Gastrointestinal issues are common in ultraraces, often leading to dropouts. NSAIDs can irritate the stomach lining, primarily due to the inhibition of prostaglandin formation, which protect the stomach lining [10]. NSAIDs, particularly at high doses, are associated with an increased risk of heart attack and stroke. This risk is more pronounced with certain COX-2 inhibitors [10].

There are no studies that have investigated a safe dose or route to take NSAIDs in races. However, evidence shows that they could exacerbate the stress of competition. Therefore, if you sign up for a marathon or an ultramarathon, you must accept that it will be uncomfortable and painful. If you can’t cope with it, then just don’t do it, but don’t put yourself at risk by trying to reduce pain – the solution may end up being worse than the “problem” itself.

Anti-inflammatories considerations

As a therapist and coach, there are circumstances where I wouldn’t recommend the use of anti-inflammatory interventions. These include acute and minor injuries, recovery from DOMS (delayed onset muscle soreness), and during competitions. There are exceptions where these interventions could be considered (always under the supervision of a physician experienced in sports injuries), such as in the case of chronic injuries or where inflammation is not properly regulated by the body. I would suggest the use of ice only if you are in a period of competitions where events are very close to each other, as in the case of stage races.

Conclusions

In summary, while anti-inflammatory therapies like NSAIDs can provide short-term relief, their long-term use and impact on muscle recovery warrant caution and further investigation. Understanding the role of anti-inflammatory interventions, inflammation in the body, and its importance in repair processes is crucial for making informed decisions about recovery strategies in sports and beyond. 

REFERENCES

1. Tidball, J.G., Mechanisms of Muscle Injury, Repair, and Regeneration, in Comprehensive Physiology. p. 2029-2062.

2. Ho, A.T.V., et al., Prostaglandin E2 is essential for efficacious skeletal muscle stem-cell function, augmenting regeneration and strength. Proc Natl Acad Sci U S A, 2017. 114(26): p. 6675-6684.

3. Mackey, A.L., et al., Rehabilitation of muscle after injury – the role of anti-inflammatory drugs. Scand J Med Sci Sports, 2012. 22(4): p. e8-14.

4. Dalle, S., et al., Ibuprofen does not impair skeletal muscle regeneration upon cardiotoxin-induced injury. Physiol Res, 2020. 69(5): p. 847-859.

5. Bateman, L.S., et al., Effects of Ibuprofen on Muscle Hypertrophy and Inflammation: a Review of Literature. Current Physical Medicine and Rehabilitation Reports, 2023. 11(1): p. 43-50.

6. Kawashima, M., et al., Icing after eccentric contraction-induced muscle damage perturbs the disappearance of necrotic muscle fibers and phenotypic dynamics of macrophages in mice. Journal of Applied Physiology, 2021. 130(5): p. 1410-1420.

7. Singh, D.P., et al., Effects of Topical Icing on Inflammation, Angiogenesis, Revascularization, and Myofiber Regeneration in Skeletal Muscle Following Contusion Injury. Front Physiol, 2017. 8: p. 93.

8. Wang, Z.R. and G.X. Ni, Is it time to put traditional cold therapy in rehabilitation of soft-tissue injuries out to pasture? World J Clin Cases, 2021. 9(17): p. 4116-4122.

9. de Souza, R.F., et al., Effects of ibuprofen during 42-km trail running on oxidative stress, muscle fatigue, muscle damage and performance: a randomized controlled trial. Res Sports Med, 2024. 32(3): p. 400-410.

10. Pannone, E. and R. Abbott, What is known about the health effects of non-steroidal anti-inflammatory drug (NSAID) use in marathon and ultraendurance running: a scoping review. BMJ Open Sport Exerc Med, 2024. 10(1): p. e001846.