Dynamic changes in dna methylation status in peripheral blood Mononuclear cells following an acute bout of exercise: Potential impact of exercise-induced elevations in interleukin-6 concentration.

The aim of the present study was to examine the relationship between interleukin (IL)-6 concentrations and DNA methylation in the peripheral blood mononuclear cells (PBMCs) of trained runners after a bout of prolonged, strenuous exercise. Eight healthy trained males completed a treadmill run at 60% vVO(2max) for 120 min followed by a 5-km time trial in a fasted condition. Whole blood samples were taken prior to, immediately before and 24 h following exercise. From these samples, PBMCs were isolated for analysis and plasma IL-6 concentrations were measured. The methylation status of DNA extracted from PBMCs was analysed using the Illumina 27k methylation beadchip platform. Global DNA methylation status was unaltered immediately and up to 24 hours following a bout of prolonged exercise in comparison to pre-exercise. Despite no change in global DNA methylation, plasma IL-6 concentrations were significantly related to the DNA methylation status of 11 genes. Our study demonstrates that the methylome is stable, while discovering a novel link between exercise-induced increases in circulating IL-6 and the DNA methylation status of 11 individual genes. Based on our preliminary findings, the mechanisms by which changes in plasma IL-6 concentrations and DNA methylation in response to exercise interact require further study.

Airway dysfunction in elite athletes--an occupational lung disease?

Airway dysfunction is prevalent in elite endurance athletes and when left untreated may impact upon both health and performance. There is now concern that the intensity of hyperpnoea necessitated by exercise at an elite level may be detrimental for an athlete's respiratory health. This article addresses the evidence of causality in this context with the aim of specifically addressing whether airway dysfunction in elite athletes should be classified as an occupational lung disease. The approach used highlights a number of concerns and facilitates recommendations to ensure airway health is maintained and optimized in this population. We conclude that elite athletes should receive the same considerations for their airway health as others with potential and relevant occupational exposures.

The reliability of the IL-6, sIL-6R and sgp130 response to a preloaded time trial.

Interleukin-6 (IL-6) is a cytokine that can mediate numerous biological actions including fatigue. Circulating IL-6 increases during prolonged exercise, and furthermore, the signalling receptors sIL-6R and sgp130 are also increased. The variability of the response of these markers to exercise is unknown; therefore, we examined the changes in these markers to a preloaded time trial bout of running. Nine males performed three identical trials where participants ran at 60% vVO2max for 2 h interspersed with 30 s at 90% vVO2max every 10 min, followed by a 5-km time trial. Blood samples were drawn at baseline, following the 2-h bout, post time trial, 1 h post time trial and the following morning. Results showed that between-subject variability (CVg) was greater than within-subject variation (CVi) for the three markers. IL-6, sIL-6R and sgp130 demonstrated a CVi of 15.3-25.5%, 15.0-17.6% and 6.2-9.4% variation, respectively, across the time points. When the data from the second and third trials were analysed independently, CVi was reduced which is supported by the time trial results for which CVi improve (4.7-2.4%). In conclusion, the results indicate that a large variation in response to exercise can be reduced following a habituation trial.

The effect of breathing an ambient low-density, hyperoxic gas on the perceived effort of breathing and maximal performance of exercise in well-trained athletes.

BACKGROUND: The role of the perception of breathing effort in the regulation of performance of maximal exercise remains unclear. AIMS: To determine whether the perceived effort of ventilation is altered through substituting a less dense gas for normal ambient air and whether this substitution affects performance of maximal incremental exercise in trained athletes. METHODS: Eight highly trained cyclists (mean SD) maximal oxygen consumption (VO(2)max) = 69.9 (7.9) (mlO(2)/kg/min) performed two randomised maximal tests in a hyperbaric chamber breathing ambient air composed of either 35% O(2)/65% N(2) (nitrox) or 35% O(2)/65% He (heliox). A ramp protocol was used in which power output was incremented at 0.5 W/s. The trials were separated by at least 48 h. The perceived effort of breathing was obtained via Borg Category Ratio Scales at 3-min intervals and at fatigue. Oxygen consumption (VO(2)) and minute ventilation (V(E)) were monitored continuously. RESULTS: Breathing heliox did not change the sensation of dyspnoea: there were no differences between trials for the Borg scales at any time point. Exercise performance was not different between the nitrox and heliox trials (peak power output = 451 (58) and 453 (56) W), nor was VO(2)max (4.96 (0.61) and 4.88 (0.65) l/min) or maximal V(E) (157 (24) and 163 (22) l/min). Between-trial variability in peak power output was less than either VO(2)max or maximal V(E). CONCLUSION: Breathing a less dense gas does not improve maximal performance of exercise or reduce the perception of breathing effort in highly trained athletes, although an attenuated submaximal tidal volume and V(E) with a concomitant reduction in VO(2) suggests an improved gas exchange and reduced O(2) cost of ventilation when breathing heliox.