Pain Relief in Sports: Effects, Risks, and Facts

Pain-Free Summary: The article summarizes what research has to say about painkillers in sports. The key question is whether painkillers can boost performance and what risks are linked to their use before or during training and competition. Studies indicate that pain relief in specific controlled tests can help athletes push harder, especially during short and intense efforts or in heat. However, there are clear downsides: repeated use can hinder training adaptation and increase the risk of health issues under stress. The conclusion is that any short-term benefits must be weighed against long-term consequences and medical risks.

Introduction

The aim of this article is—as always—to present the research in this area. We explore the possible negative physiological and psychological effects of using painkillers, and also highlight studies where researchers have noted performance enhancements in controlled trials with placebo compared to painkillers.

We are cautious about using painkillers in sports and do not advocate for their use. While we understand the potential benefits in certain situations, our fundamental stance is that they should not be routinely taken in conjunction with training or competition. That said, let's get to the facts—the current state of research is as follows.

Background

Painkillers, or non-steroidal anti-inflammatory drugs (NSAIDs) as they are formally known, are a group of medications with different active ingredients but often the same purpose: to reduce pain and inflammation. You're likely familiar with paracetamol (e.g. Alvedon, Panodil), ibuprofen (e.g. Ipren, Ibumetin), and acetylsalicylic acid (e.g. Aspirin, Bamyl). For the record, paracetamol isn't technically an NSAID, but we'll leave that detail aside because the essential point is simple: the pain becomes less noticeable.

A bit of nerdy detail is enjoyable though. Many over-the-counter anti-inflammatory drugs commonly work by inhibiting the enzyme cyclooxygenase (COX) — in various forms. COX is part of the process that leads to prostaglandin production, which amplifies pain signals in the body. As prostaglandins increase in pain and inflammation, the perceived pain also rises. By inhibiting COX, prostaglandin formation is reduced, making the pain feel less intense.

Use of Painkillers

Painkillers are used before and primarily during competition. Studies reveal that the longer the competition, the greater the likelihood that participants will take painkillers.

A study on ultramarathon runners who ran either 44 km, 67 km, or 112 km showed widespread use:

• 44 km – 35% used painkillers in connection with the race
• 67 km – 48% used painkillers in connection with the race
• 112 km – 60% used painkillers in connection with the race

Usage correlates with 50–60% of ultramarathon runners experiencing muscle and skeletal pain, primarily in the legs (ankles and knees are most common), leading them to take painkillers during the race (source). But these statistics aren't unique to ultrarunners — regardless of distance, from half-marathon to ultra, about 50–60% also use painkillers during training. The figure is similarly high among full-distance triathletes. For half-marathon and marathon runners, approximately 30% use painkillers during competition.

Consumption is highest among runners and triathletes who subject their bodies to considerable mechanical strain. Among cyclists, it's significantly lower — only 5–10% of participants in certain ultra distances (e.g. 24 h mountain bike) report usage. The conclusion is straightforward: where the physical strain is greater, usage is also higher.

That may have been a lot of statistics, but the frequent use of painkillers is one of the reasons this article is needed.

Painkillers as Performance Enhancers

To get stronger or more resilient, we often need to push our bodies past the comfort zone — and that hurts. The final minute of the last interval, the last minutes of an all-out 20-minute session, or the final sprint in a race are often the toughest parts. Here, the idea of taking painkillers becomes logical: dull the pain so you can lift heavier, pedal more watts, or run 30 seconds longer.

But what does the research show? Painkillers do not increase performance for a given workload per se. The first studies in the 1990s gave participants 650 mg of aspirin before a 3.2 km time trial and saw no measurable performance increase (source). Another study increased the dose to 1000 mg of aspirin and ran participants through an incremental cycling test to exhaustion without performance improvement (source).

In more modern studies, research groups have tested higher doses — around 1500 mg (e.g., 3x500 mg or 5x300–500 mg depending on the medication) — and have, in several cases, seen performance increases in tests that go to exhaustion or in sprint tests. Performance increases have varied, often between about 4% up to as much as 17% in hot conditions. Participants can push themselves harder without reporting higher perceived exertion, indicating that it's the pain experience being diminished — not the actual work capacity.

Active Dose

Summing up the research, it seems — perhaps unsurprisingly — that painkillers can enhance performance if the dose is sufficiently high. Doses over approximately 1000 mg seem necessary, and the effect is primarily seen in short, intense efforts (e.g., intervals or tests to exhaustion). The studies have used protocols such as 8x30 s with 2 min rest, a 16 km time trial on a test bike, or a 20–25 min time trial in 30-degree heat — situations where the feeling of exertion and pain often limit performance before physiological capacity is exhausted.

For longer distances, like ultramarathons where use is high, it's reasonable to assume that painkillers can be performance-enhancing by blocking pain so the participant can continue despite pain and fatigue. But it's difficult to quantify exactly how much performance increases in real, hard-to-control environments (e.g., during 24-hour mountain biking in the mountains).

A review article from 2017 summarizes the research and broadly shows that yes, painkillers can enhance performance in several disciplines and situations when intake is around 1500 mg or 20 mg per kg of body weight. Especially in heat, paracetamol seems to help lower body temperature during performance (which can provide a performance advantage).

The Downside of Painkillers

Gaining an acute performance advantage is one thing — but what happens in the long run? Unfortunately, there are clear drawbacks.

Taking NSAIDs inhibits protein synthesis after training. In practical terms, this means that muscles receive a weaker signal to repair, recover, and grow. In short: some of the stimulus you want from training diminishes if you take painkillers at the same time.

In a controlled study where participants were given 1200 mg of ibuprofen daily during an eight-week strength training period, it was observed that the control group increased muscle volume by 7.5%, while the ibuprofen group only increased by 3.7%. That's about halved muscle growth over the period. However, no difference in mitochondrial function was observed between the groups.

A plausible mechanism is that the inflammation marker interleukin-6 (IL-6) was inhibited. The inflammation that occurs after training is part of the signaling that drives repair and adaptation — so it's needed for maximum training adaptation. Trying to suppress that inflammation with anti-inflammatory drugs is therefore often counterproductive if the goal is maximum development.

Additionally, the risk of both acute kidney injury and hyponatremia increases with the use of painkillers during activity, especially when combined with dehydration or extreme conditions.

Summary

The following points summarize the situation:

• Acute perspective: Painkillers can provide performance enhancement in several situations, especially during short, intense efforts or in heat, and in doses around 1500 mg or approximately 20 mg/kg body weight.
• Chronic perspective: Regular or recurring use of NSAIDs in conjunction with training decreases the training stimulus by inhibiting protein synthesis and inflammation-driven repair processes — resulting in poorer adaptive results over time.
• Health risks: Increased risk of kidney injury, hyponatremia, and potentially other side effects, particularly with prolonged use or under extreme conditions.
• Pragmatic view: We understand that elite sports sometimes involve taking calculated risks to avoid a DNF in an A-race. But make a more informed decision: weigh the short-term gain against the risk of prolonged recovery, poorer long-term development, and increased injury risk.

Painkillers can thus enhance performance in many respects. At the same time, they strain the kidneys and liver, and the risk of worsening an injury or prolonging healing time is higher than if you let the body signal pain and rest. Running several miles with a sore knee may seem worth it at the moment — but consider the cost in training development and injury risk down the road.

It seems that paracetamol and NSAIDs have the potential to improve exercise performance by decreasing the activation of higher brain structures and hence, reducing perception of effort and exercise-induced pain.