The Influence of NSAIDs on Physiologic Processes and Exercise

Introduction

Non-Sterodial Ani-Inflammatory Drugs (NSAIDs), including acetaminophen (Asprin) and Ibuprophen, simply put, reduce inflammation and pain. NSAIDs are widely and commonly used, which is why researchers are countinuously studying the risks and benefits of their effects on the human body. 

NSAIDs work by inhibiting the activity of an enzyme called cycoloxygenase (COX), which is crucial in the formation of prostaglandins. Prostaglandins play a role in the generation of pain and in the inflammatory response; however, they also have roles in many other bodily functions. When NSAID's inhibit prostaglandin synthesis they can reduce pain and inflammation, but they can also hamper gastrointestinal functions and post-exercise protein synthesis, as well as cause a number of other positive and negative side effects. These effects on physiological processes and exercise are further discussed for the following body systems: muscular, cardiovascular, metabolic, pulmonary, neuromotor and gastrointestinal. 

Muscular

Based on the literature, the effects of NSAIDs on the muscular system differs for young individuals vs. old individuals, acute vs. chronic use, and for timing of use (pre vs. post exercise) *NOTE: include additional supporting refferences here. 

Young vs. Old

Recent studies have revealed that older adults who consume NSAIDs have greater muscle strength gain and hypertrophy from resistance training compared to older adults who do not consume NSAIDs. These findings were contrary to the researchers initial beliefs on the effects of NSAIDs on the muscular system adaptations to resistance training, and so they went on to research the mechanisms possibly responsible for their findings. The mechanisms that the researches concluded were at least partially responsible for their initial findinwer were, 1) NSAIDs reduced muscle loss by reducing the amount of IL-6 and MuRF-1, which promote muscle loss, 2) NSAIDs induced PGF2a receptor upregulation, which increased skeletal muscle sensitivity to PGF2a, and thus, stimulation of protein synthesis. On the contrary, NSAIDs also supressed PGF2a, which would reduce protein synthesis stimulation. Although overall, these mechanims inhibited protein breakdown more than they inhibited protein synthesis, which resulted in an increased net muscle protein balance. These studies involved participants between the ages of 60 and 85, which shows that the effects of NSAIDs may be age-dependent. Even though NSAIDs may have a beneficial effect on the muscular system in older adults, consumers of NSAIDs need to address the effects of NSAIDs on other body systems. The previously discussed studies did not address other body systems and only assessed the effects of NSAIDs on the muscular system after a 12-week resistance training program with particpants consuming 4 g/day and 1.2 g/day of acetaminophen and ibuprophen, respectfully. Further reseach should address the effects of NSAIDs on older adults after an even more long-term time period. 

Timing of Use (Pre vs. Post Exercise)

Many athletes take NSAIDs before physical activity in order to prevent the inflammation and/or pain that may occur. Some clinical evidence involving surgical trials supports these claims, finding that using NSAIDS prior to an inflammatory event could reduce inflammatory response, pain, and recovery time. In exercise induced muscle damage, rather than surgically induced, studies have shown that pre-exercise administration of NSAIDs could reduce the amounts of creatine kinase circulating after exercise as compared to a placebo group. This difference in creatine kinase levels may illustrate that less muscle damage occurred in the treatment group.
Similar studies have also shown that NSAIDs as a preventative measure have little to no effect. In addition to these unclear results, frequent and preemptive NSAID use could allow the pain of an underlying condition to go unnoticed and become further damaged as the athlete continues to put stress on the injury. The overall negative effects of frequent use of NSAIDs as discussed below could outweigh the possible benefits of pre-exercise use. More studies are needed to determine the efficacy of taking NSAIDs before exercise.