Plasma cytokine and exertional responses in relation to exercise intensity and volume of exercising muscle mass during arm-crank ergometry.

This original study investigated the effect of submaximal exercise intensity and volume of contracting muscle mass on plasma inflammation-mediating cytokine and perceived exertional responses to acute arm-crank ergometry (ACE). Twelve recreationally active but upper limb untrained males performed 30 min of (i) low-intensity (40% peak oxygen uptake) ACE (LOW); (ii) moderate-intensity (60% peak oxygen uptake) ACE (MOD); and (iii) concurrent low-intensity (40% peak oxygen uptake) ACE plus lower limb cycle ergometry to match total power output in MOD (HYB). Plasma concentrations of interleukin (IL)-6, IL-10, IL-1ra, adrenaline, and cortisol were determined at rest, immediately postexercise, and 1 h and 2 h postexercise. Heart rate (HR) and differentiated ratings of perceived exertion (RPE) were also recorded. Plasma IL-6 concentrations were elevated (p < 0.05) immediately postexercise and 1 h postexercise (∼ 2.5-fold) in all trials and 2 h postexercise in MOD (3-fold). Plasma IL-1ra concentrations were elevated (p < 0.05) 2 h postexercise in MOD only (2-fold). No plasma IL-10, cortisol, and adrenaline responses were observed. HR and differentiated RPE were significantly higher during MOD than HYB and LOW. Peripheral RPE were significantly higher than central and overall RPE in each trial. Thirty minutes of moderate intensity ACE initiated a plasma cytokine response associated with the protective effect of regular exercise against cardiovascular and metabolic disease risk. Further work is required to establish an optimal intensity and duration of upper limb exercise to maximise the anti-inflammatory potential whilst managing the risk of over-use injury.