NSAIDs (Ibuprofen, Acetaminophen/Paracetamol) for runners, impairs healing and interferes with hydration

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Acetaminophen (brand names Tylenol, aspirin-free Anacin, Excedrin, and numerous cold medicines)

NSAIDs are Non-Steroidal Anti-Inflammatory Drugs, the most common are Ibuprofen (Advil, Motrin), Acetaminophen/Paracetamol (Tylenol, aspirin-free Anacin, Excedrin, and numerous cold medicines) and Aspirin. They work by inhibiting a particular enzyme (Cyclooxygenase) which reduces pain, fever and inflammation. NSAIDs are generally bad for runners, impairing healing, masking symptoms, interfering with hydration and in extreme situations can be life threatening. Ibuprofen use is so common among runners that it is sometimes called "Vitamin I"[1].

1 NSAIDs and Healing

The inflammation response of our bodies is a key part of the healing process. Using NSAIDs to reduce the inflammation has been shown to impair healing in different tissue types:

  • Muscles. [2]. A 2001 study showed that Ibuprofen and Acetaminiaphen reduce muscle growth after eccentric exercise. Another study[3] on muscle damage and NSAIDs showed impaired recovery in the early stages of healing. There was some increased Protein synthesis with NSAIDs in latter stages of healing, but the muscles were still weaker 28 days after injury. Other studies[4][5] have shown that four days after injury, NSAIDs resulted in very little muscle regeneration compared with no drugs.
  • Tendons. A primate study[6] showed "a marked decrease in the breaking strength of tendons at four and six weeks in the ibuprofen-treated animals". Another animal study[7] showed treated tendons were 32% weaker than their untested counterparts.
  • Bone-Tendon Junctions. An animal study[8] of rotator cuff injuries shows that NSAID usage resulted in injuries that did not heal, and those that did heal were weaker than those without NSAID. To quote from the study "Given that NSAID administration was discontinued after 14 days yet affected load-to-failure eight weeks following repair, it appears that inhibition of the early events in the inflammatory cascade has a lasting negative effect on tendon-to-bone healing," Dr. Rodeo said.
  • Cartilage. NSAIDs have been shown[9] to impair the healing of bone and cartilage in rabbits.
  • Bone fractures. Tests on rats shows that a NSAID (Celecoxib) in the early stages of bone healing impaired healing, producing a weaker repair.[10] A study [11] in 2004 declared " Nonsteroidal anti-inflammatory drugs continue to be prescribed as analgesics for patients with healing fractures even though these drugs diminish bone formation, healing, and remodeling".

1.1 Counterpoint

While there is extensive experimental evidence for NSAIDs impairing healing, there are also some studies that show no change with NSAID use, and a few that indicated improved healing. For instance, one study[12] showed that using an NSAID for 6 days after injury resulted in a 42% increased ligament strength at day 14, though there was no change by day 21. Another study[13] showed that an NSAID did not change ligament healing, but did improve the strength of the uninjured ligaments. However, my reading indicates that the preponderance of evidence shows NSAIDs impair healing.

1.2 Ice, Inflammation and Healing

If NSAIDs are bad for healing, should we treat with ice? So far I have found no definitive studies, but ice has a differenct mechanism of action from NSAIDs. By cooling the tissues, ice temporarily reduces inflammation, thereby flushing the wound. It does not directly impact any of the body's enzymes or other processes. If applied for a longer period of time, ice will produce a periodic increase in blood supply that creates a further flushing effect. I have found that ice can produce dramatic improvements in healing speed. See Cryotherapy - Ice for Healing for more details.

2 NSAIDs and Acute kidney failure

Kidney failure while running is extremely rare, and seems to require multiple factors to come together. Looking at the Comrades Marathon, a 90 Km/56 Mile ultramarathon in South Africa, there have only been 19 cases of kidney failure between 1969 and 1986, it even though thousands of people participate each year[14]. The following are considered factors in acute kidney failure related to running.

  • Dehydration. Exercise reduces blood flow to the kidneys and dehydration makes this worse.
  • NSAIDs. NSAIDs also reduce blood flow to the kidneys[15]. NSAIDs reduce prostaglandin production, and prostaglandins are vital to maintaining blood flow to the kidneys. While NSAIDs are considered safe drugs, NSAIDs are associated with a relatively high incidence of adverse drug reactions involving the kidneys. Generally NSAID side effects are restricted to individuals with predisposition to kidney problems, so extra care should be taken if you have a history of kidney problems. However, athletes push their bodies to extremes, so what applies to the general population may not be valid for runners. One runner was told[16] by doctors that 2400mg Ibuprofen in an ultramarathon was a contributing factor to his kidney failure.
  • Rhabdomyolysis. All strenuous exercise causes some muscle damage, but this is generally resolved without a problem. However large amounts of a Protein called myoglobin from damaged muscle can cause a condition called rhabdomyolysis (AKA 'rhabdo'). While serious rhabdomyolysis is rare, it is worth understanding one key symptom, which is low volume, dark urine, often likened to 'coca-cola'. The other symptoms include severe, incapacitating muscle pain and elevated levels of creatine kinase (CK) in the blood (which requires a specialist test). Some individuals[17] have a genetic condition that makes rhabdomyolysis possible after relatively moderate exercise. Rhabdomyolysis is also more likely after eccentric exercise, such as Downhill Running.
  • Sickness. A viral or bacterial infection is often a factor in exercise related kidney failure.

Looking at the analysis[15] of nine cases of continued kidney failure in Comrades Marathon, seven had taken NSAIDs, four may have had a viral or bacterial infection. The combination of dehydration, rhabdomyolysis, infection and NSAIDs are a perfect storm for the kidneys.

3 NSAIDs and Hyponatremia

The kidneys are responsible for removing excess fluid from the blood as well as excreting or withholding sodium. If kidney function is compromised, then this can result in Hyponatremia, which can be fatal. Some studies[18][19][20] have shown a correlation between NSAID use in races and Hyponatremia, but others[21][22] have not. Using NSAIDs when hydration is a concern increases the risk of problems occuring.

4 NSAIDs and Sickness

Because a bacterial or viral infection puts more stress on the body, including the kidneys, taking NSAIDs and continuing to run increases your risk of complications. If the sickness is too bad to run without NSAIDs, you probably shouldn't run.

5 NSAIDs for Pain Reduction

The primary purpose of NSAIDs is generally for reducing pain, and they are remarkably effective at achieving this. If you need a painkiller, acetaminophen is probably a better choice than ibuprofen, though be careful as it's easy to overdose on Acetaminophen (see below). Acetaminophen has limited anti-inflammatory properties, so it shouldn't impair healing as much as ibuprofen, but it is still good as a painkiller. Combining acetaminophen or other NSAIDs with Caffeine further improves their painkilling effectiveness. After a major race I can sometimes have so much leg pain that I can't sleep and a little acetaminophen can make all the difference. While the acetaminophen may impair healing somewhat I believe the trade-off in improved sleep is worthwhile. After all, the lack of sleep itself will impair healing, so it's a reasonable compromise.

6 NSAIDs and DOMS

Main article: Delayed Onset Muscle Soreness

Delayed Onset Muscle Soreness (DOMS) generally occurs between 24 and 72 hours after unusual or severe exercise, such as racing a marathon or Downhill Running. The use of NSAIDs to prevent or treat DOMS has been widely researched, with somewhat mixed results. Even scholarly reviews of the research have differing conclusions[23] [24] [25][26]. My conclusions based on the available research are:

  • The most common NSAIDs (Ibuprofen, Acetaminophen (Paracetamol), and Aspirin) are unlikely to help with DOMS.
  • There is some evidence that Naproxen may be more effective than the common NSAIDs. There is not enough evidence to reach a conclusion on Diclofenac, Codeine, Rofecoxib, Ketoprofen, or Bromelain.
  • If an NSAID is taken for DOMS, it should probably be taken immediately after the damaging exercise rather than waiting until the soreness develops.
  • It seems likely that taking an NSAID for DOMS will reduce the muscular growth that would normally occur as part of the recovery.
    • In one study, rabbits treated with flurbiprofen after DOMS inducing exercise regained more strength after 3-7 days, but between days 7 and 28 days the treated rabbits became weaker while the controls became stronger[27]. This is only one study, and on animals, but it is rather troubling as none of the human studies look at the results over this time period.

6.1 A Summary of the Research on NSAIDs and DOMS

The table below summarizes the research I located on the effect of NSAIDs on DOMS in humans. I've only considered the primary DOMS markers of soreness (pain) and weakness, rather than including things like blood enzymes. For each NSAID I've shown how many studies show an improvement and how many studies show no effect.

NSAID Soreness Weakness
Ibuprofen 2xImproved[28][29]

7xNo Effect[30][31][32] [33][34][35][36]

1xMaybe[28]

8xNo Effect[30][31][32] [33][34][35][29][36]

Ibuprofen Gel 1xNo Effect[37]
Acetaminophen (Paracetamol) 2xNo Effect[38][39]
Aspirin 2xImproved[40][41]

2xNo Effect[38][39]

2xNo Effect[40][41]
Naproxen 4xImproved[42][43][44][45]

1xNo Effect[46]

3xImproved[42][43][44]

1xNo Effect[46]

Diclofenac Possible slight reduction[47]
Codeine 1xNo Effect[38]
Rofecoxib 1xNo Effect[48]
Ketoprofen 1xImproved[49] 1xImproved[49]
Bromelain 1xNo Effect[36]

7 NSAIDs and Intestinal Damage

As little as one hour of intense cycling can result in indications of small intestinal damage[50]. This is believed to be due to the redirection of blood away from the digestive system and towards the active muscles. These markers are significantly higher if 400mg ibuprofen (the standard single adult dose) is taken before the exercise[51]. The marker used is Plasma Intestinal Fatty Acid Binding Protein which is an early marker of intestinal necrosis[52].

The level of a marker of intestinal damage during and after 60 minutes of cycling at 70% V̇O2max.

8 NSAIDs and wound healing

Main article: Popping Blisters

Ibuprofen, and possibly other NSAIDs, impair wound healing and should be avoided[53][54].

9 NSAIDs and Racing

Taking NSAIDs in ultramarathon events can improve performance by reducing pain and acute inflammation, but doing so represents a significant risk. There is some evidence[55] [56] that many runners taking NSAIDs have the same level of pain and greater damage markers compared with non-users. This may be because the runners push themselves to a similar level of pain, with the NSAIDs allowing them to do more damage.

  • It seems likely that NSAIDs will increase the risk of injury rather than reducing it, as the symptoms of damage will be masked.
  • The most common NSAID for racing seems to be ibuprofen. I've not seen any evidence of the relative effectiveness of different NSAIDs on performance.
  • It is better to take liquid ibuprofen than tablets or capsules. The tablets and capsules take longer to dissolve and if you have a digestive problem they may not be fully absorbed. You can chew the tablets, but this is unpleasant and ibuprofen can irritate your mouth and throat slightly, so the liquid form is best. It's obviously harder to transport, but you can fill an old film canister with a dose.
  • Before an ultramarathon race, you should think through under what circumstances you will consider using NSAIDs and what dosage. Make sure your crew knows that you're taking NSAIDs in case anything happens.
  • Extra care should be taken when NSAIDs are used in combination with dehydration, sickness or running the causes serious muscle damage.
  • Taking NSAIDs in marathon or shorter races is probably ineffective as the level of damage seen is not as great as in ultramarathon events.
  • If you need NSAIDs to start a race, you probably should not compete.

10 Longer Term NSAID usage

Using NSAIDs for longer periods of time can lead to serious health problems and can be fatal. I have a running friend who had a bleeding ulcer from using Ibuprofen, which is a known[57] side effect. The likelihood of a bleeding or perforated ulcer goes up with time, from 1% after 3-6 months, to 2-4% after 12 months. 35% of long term Ibuprofen users get an ulcer[58], which are grim odds.

11 Acetaminophen Overdose Danger (AKA Paracetamol, Tylenol)

Acetaminophen does not have the same risk of ulcers, but it is linked to liver damage, especially in those who drink alcohol. Acetaminophen is the leading cause of acute liver failure[59][60]. There are concerns[61] that even the standard dose can cause changes in liver function. Acetaminophen can cause delayed symptoms[60], with people seeking medical help up to 5 days after the overdose (20% < 12 hours, 35% 12-24 hours, 45% 24 hours+). Overdoses of Acetaminophen can be caused by taking slightly too much over several days, with the toxicity building up[60]. This problem is again exacerbated by those taking alcohol with Acetaminophen[60]. (One factor that increases the risk is that some common medications, such as cold remedies, include Acetaminophen. If people do not add in the dose of Acetaminophen from these other sources, it is easy to unwittingly exceed the safe dosage.)

12 Tangent - Is Acetaminophen really an NSAID?

There are differing opinions around the classification of Acetaminophen as an NSAID with some resources[62] stating it is not an NSAID. While Acetaminophen has limited anti-inflammatory properties, it shares the same mechanism of action with most NSAIDs of inhibiting the COX enzyme and the inhibition of prostaglandin synthesis. It is therefore reasonable and useful to classify Acetaminophen as an NSAID.

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