An acute naproxen dose does not affect core temperature or Interleukin-6 during cycling in a hot environment

Non-steroidal anti-inflammatory drugs’anti-pyretic and anti-inflammatory effects has led some individuals to theorize these medications may blunt core body temperature(Tc)increases during exercise.We utilized a double-blind,randomized,and counterbalanced cross-over design to examine the effects of a 24-h naproxen dose(3–220 mg naproxen pills)and placebo(0 mg naproxen)on Tc and plasma interleukin-6(IL-6)concentrations during cycling in a hot or ambient environment.Participants(n=11;6 male,5 female;age=27.8±6.5 years,weight=79.1±17.9 kg,height=177±9.5 cm)completed 4 conditions:1)placebo and ambient(Control);2)placebo and heat(Heat);3)naproxen and ambient(Npx);and 4)naproxen and heat(NpxHeat).Dependent measures were taken before,during,and immediately after 90 min of cycling and then 3 h after cycling.Overall,Tc significantly increased pre-(37.1±0.4℃)to post-cycling(38.2±0.3℃,F_(1.7,67.3)=150.5,p<0.001)and decreased during rest(37.0±0.3℃,F_(2.0,81.5)=201.6,p<0.001).Rate of change or maximum Tc were not significantly different between conditions.IL-6 increased pre-(0.54±0.06 pg/ml)to post-exercise(2.46±0.28 pg/ml,p<0.001)and remained significantly higher than pre-at 3 h post-(1.17±0.14 pg/ml,95%CI=-1.01 to-0.23,p=0.001).No significant IL-6 differences occurred between conditions.A 24-h,over-the-counter naproxen dose did not significantly affect Tc or IL-6 among males and females cycling in hot or ambient environments.

A 24 hour naproxen dose on gastrointestinal distress and performance during cycling in the heat

Using a double-blind,randomized and counterbalanced,cross-over design,we assessed naproxen's effects on gastrointestinal(GI)distress and performance in eleven volunteers(6 male,5 female).Participants completed 4 trials:1)placebo and ambient);2)placebo and heat;3)naproxen and ambient;and 4)naproxen and heat.Independent variables were one placebo or 220 mg naproxen pill every 8 h(h)for 24 h and ambient(22.7±1.8℃)or thermal environment(35.7±1.3℃).Participants cycled 80 min at a steady heart rate then 10 min for maximum distance.Perceived exertion was measured throughout cycling.Gastrointestinal distress was assessed pre-,during,post-,3 h post-,and 24 h post-cycling using a GI index for upper,lower,and systemic symptoms.No statistically significant differences occurred between conditions at any time for GI symptoms or perceived exertion,distance,or heart rate during maximum effort.A 24 h naproxen dose did not significantly affect performance or cause more frequent or serious GI distress when participants were euhydrated and cycling at moderate intensity in a thermal environment.