Mucosal immune and physiological responses to exercise in wheelchair athletes

Apart from motor and sensory function loss, an injury to the spinal cord can cause sympathetic dysfunction, which has been shown to affect immune responses. In this thesis, data from five experimental studies have been collected to compare physiological and psychophysiological exercise responses between wheelchair athlete subgroups with different disabilities (tetraplegic, paraplegic, and non-spinal cord-injured). In two preparatory studies, physiological exercise responses to exhaustive (Chapter 4) and submaximal exercise (Chapter 5) were investigated in all three disability subgroups. Whilst reliability measures for peak oxygen uptake (VO2peak) were in a range observed previously in able-bodied athletes, the variation in tetraplegic athletes was larger when expressed relative to their VO2peak, questioning the use of this variable to track small changes in aerobic capacity in athletic populations. Submaximal physiological and psychophysiological exercise responses were found to be similar between disability subgroups when expressed as a percentage of VO2peak, justifying the protocol used in the laboratory study on mucosal immune function, which was based on the same percentages of VO2peak for all disability subgroups. The most extensive study of this thesis, detailed in Chapter 6, showed that single laboratory-controlled 60-min exercise sessions increase both salivary secretory immunoglobulin A (sIgA), a marker of mucosal immunity, and α-amylase, a marker of sympathetic activation in all three disability subgroups. However, the impaired sympathetic nervous system in tetraplegic athletes seemed to influence the fine-tuning of their sIgA response when compared with paraplegic and non-spinal cord-injured athletes, resulting in a larger exercise-induced increase of sIgA secretion rate when compared to paraplegic and non-spinal cord-injured athletes. Based on these results, the study detailed in Chapter 7 investigated sIgA responses in tetraplegic athletes during wheelchair rugby court training. Despite their disability, these athletes showed responses thought to be governed by the sympathetic nervous system, such as reductions of saliva flow rate as a result of strenuous exercise. Similarly, the responses observed in Chapter 8 imply a comparable trend of chronic sIgA exercise responses in tetraplegic athletes as found in the able-bodied population, namely a decrease in sIgA secretion rate during periods of heavy training. These are the first studies in wheelchair athlete populations to investigate mucosal immune responses. Interestingly, despite the disruption of their sympathetic nervous system, some responses in tetraplegic athletes are comparable with findings in able-bodied populations. It is possible that due to their highly trained nature, these tetraplegic individuals are able to compensate for their loss of central sympathetic innervation. This may be by way of adapted spinal reflex or parasympathetic nervous system activity, or increased sensitivity of receptors involved in autonomic pathways. Therefore, sympathetic nervous function in tetraplegic athletes may be qualitatively altered, but in parts still be functional

Editorial: Adapted sports:Wheeled-mobility, exercise and health

Editorial on the Research Topic Adapted sports: wheeled-mobility, exercise and health by Vegter RJK, Veeger DHEJ, Goosey-Tolfrey VL and Leicht CA. (2002) Front. Rehabilit. Sci. 3: 1015179. doi: 10.3389/fresc.2022.1015179.</p

Increasing heat storage by wearing extra clothing during upper body exercise up-regulates heat shock protein 70 but does not modify the cytokine response

Plasma heat shock protein 70 (HSP70) concentrations rise during heat stress, which can independently induce cytokine production. Upper body exercise normally results in modest body temperature elevations. The aim of this study was to investigate the impacts of additional clothing on the body temperature, cytokine and HSP70 responses during this exercise modality. Thirteen males performed 45-min constant-load arm cranking at 63% maximum aerobic power (62 ± 7%V̇O2peak) in either a non-permeable whole-body suit (intervention, INT) or shorts and T-shirt (control, CON). Exercise resulted in a significant increase of IL-6 and IL-1ra plasma concentrations (P 0.19). The increase in HSP70 from pre to post was only significant for INT (0.12 ± 0.11ng∙mL−1, P < 0.01 vs. 0.04 ± 0.18 ng∙mL−1, P = 0.77). Immediately following exercise, Tcore was elevated by 0.46 ± 0.29 (INT) and 0.37 ± 0.23ºC (CON), respectively (P < 0.01), with no difference between conditions (P = 0.16). The rise in mean Tskin (2.88 ± 0.50 and 0.30 ± 0.89ºC, respectively) and maximum heat storage (3.24 ± 1.08 and 1.20 ± 1.04 J∙g−1, respectively) was higher during INT (P < 0.01). Despite large differences in heat storage between conditions, the HSP70 elevations during INT, even though significant, were very modest. Possibly, the Tcore elevations were too low to induce a more pronounced HSP70 response to ultimately affect cytokine productio

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

This paper was accepted for publication in the journa

Modality-specific training adaptations – do they lead to a dampened acute inflammatory response to exercise?

While adaptations to a short-term training program can dampen the acute inflammatory response to exercise, less is known about the influence of chronic modality-specific adaptations to training. This study compares the acute inflammatory response to upper- and lower-body interval exercise in individuals chronically trained in these respective modalities. Ninety minutes of interval exercise matched for relative power output on an arm-crank (ARM) and cycle ergometer (LEG) was performed by 8 trained paddlers and 8 trained cyclists. Blood samples were taken before and after exercise. Interleukin-6 (IL-6) concentrations were analysed in plasma, while the expression of intracellular heat shock protein 72 (iHsp72) was assessed in monocytes. IL-6 was increased following both modalities (fold change – ARM: 7.23 ± 3.56, p < 0.001; LEG: 9.03 ± 4.82, p < 0.001), in both groups (cyclists, p < 0.001; paddlers, p < 0.001), but the increase was smaller in ARM compared with LEG (time × modality, p < 0.001). ARM induced a smaller iHsp72 response compared with LEG (fold change – ARM: 1.07 ± 0.14, p = 0.102; LEG: 1.18 ± 0.14, p < 0.001; time × modality, p = 0.039). Following ARM, iHsp72 expression was increased in the cyclists only (fold change cyclists: 1.12 ± 0.11, p = 0.018; paddlers: 1.03 ± 0.17, p = 0.647), while iHsp72 expression following LEG was increased in both groups (fold change cyclists: 1.14 ± 0.15, p = 0.027; paddlers: 1.22 ± 0.13, p < 0.001). Taken together, the acute inflammatory response to lower-body interval exercise was larger compared with work-matched upper-body interval exercise. Moreover, adaptations to upper-body exercise training dampened the iHsp72 response to this modality. Therefore, exercise may be less effective in reducing chronic low-grade inflammation in individuals relying on their upper body, such as wheelchair users.The accepted manuscript in pdf format is listed with the files at the bottom of this page. The presentation of the authors' names and (or) special characters in the title of the manuscript may differ slightly between what is listed on this page and what is listed in the pdf file of the accepted manuscript; that in the pdf file of the accepted manuscript is what was submitted by the author

Spinal Cord Injury Level and the Circulating Cytokine Response to Strenuous Exercise

This is a non-final version of an article published in final form in: PAULSON, T.A.W. ... et al., 2013. Spinal cord injury level and the circulating cytokine response to strenuous exercise. Medicine and Science in Sports and Exercise, 45 (9), pp. 1649-1655. URL: http://dx.doi.org/10.1249/MSS.0b013e31828f9bbb.PURPOSE: A complete spinal cord injury (SCI) above the 6th thoracic vertebra (T6) results in the loss of sympathetic innervation of the adrenal medulla. This study examined the effect of a complete SCI above and below T6 on plasma concentrations of epinephrine, circulating interleukin (IL)-6 and other inflammatory cytokines in response to acute strenuous exercise. METHODS: Twenty-six elite male wheelchair athletes (8=C6-C7 tetraplegic (TETRA); 10=T6- L1 paraplegic (PARA); 8=non-spinal cord injured controls (NON-SCI)) performed a submaximal exercise test followed by a graded exercise to exhaustion on a motorised treadmill. Blood samples were taken pre-exercise, post-exercise and 30 min post-exercise (post30) and analysed for concentrations of IL-6, IL-10, IL-1 receptor-antagonist (IL-1ra), tumor necrosis factor-alpha (TNF-α), epinephrine and cortisol. RESULTS: Circulating IL-6 concentration was significantly elevated at post-exercise and post30 (~5-fold) in NON-SCI and PARA (P=0.003) whereas concentrations in TETRA did not change significantly from pre-exercise values. IL-10, IL-1ra and TNF-α were unaffected by exercise in all groups, however both SCI groups presented elevated concentrations of IL-10 compared with NONSCI (P=0.001). At post-exercise, epinephrine concentrations were significantly higher than pre-exercise and post30 concentrations in NON-SCI (~3-fold) and PARA (~2-fold) (P=0.02). Plasma epinephrine concentrations were unchanged in TETRA throughout exercise; concentrations were significantly lower than NON-SCI and PARA at all-time points. Plasma cortisol concentrations were significantly elevated in all groups at post-exercise and post30 compared with pre-exercise (P<0.001). Total exercise time was similar between groups (NON-SCI= 38±6; PARA= 35±5; TETRA= 36±5 min). CONCLUSION: These findings suggest the sympathetic nervous system plays an important regulatory role in the circulating IL-6 response to exercise and has implications for the metabolic and inflammatory responses to exercise in individuals with injuries above T6

Exercise intensity and its impact on relationships between salivary immunoglobulin A, saliva flow rate and plasma cortisol concentration

This is an Open Access Article. It is published by Springer under the Creative Commons Attribution 4.0 Unported Licence (CC BY). Full details of this licence are available at: http://creativecommons.org/licenses/by/4.0/Introduction Salivary secretory immunoglobulin A (sIgA), saliva flow rate and plasma cortisol concentrations have been shown to be influenced by exercise, particularly the intensity exercise is performed at, and circadian variation. The autonomic nervous system partly regulates salivary secretion, but it is not yet known whether cortisol also explains some variation in salivary parameters. Methods Twelve moderately trained male individuals (V̇ O2peak legs: 46.2±6.8 mL·kg−1·min−1) performed three 45-min constant load exercise trials in the morning: arm cranking exercise at 60%V̇ O2peak arms; moderate cycling at 60%V̇ O2peak legs; and easy cycling at 60%V̇ O2peak arms. Timed saliva samples and blood samples for plasma cortisol concentration determination were obtained before, post, 2 h post, and 4 h post-exercise. Saliva was collected in an additional resting trial at the same time points. Results At each time point for each exercise trial, negative correlations between cortisol and saliva flow rate (explaining 25±17% of the variance, R2=0.002–0.46) and positive correlations between cortisol and sIgA concentration (explaining 8±8% of the variance R2=0.002–0.24) were found. Saliva flow rate increased over time, whereas sIgA concentration and cortisol decreased over time for all trials (P<0.05), there was no effect of time for sIgA secretion rate (P=0.16). Conclusion These results show a relationship between cortisol and saliva flow rate, which directly impacts on the concentration of salivary analytes. This study further confirms circadian variations in salivary parameters which must be acknowledged when standardising salivary data collection

Arm and Intensity-Matched Leg Exercise Induce Similar Inflammatory Responses

This is a non-final version of an article published in final form in LEICHT, C.A. ... et al, 2016. Arm and intensity-matched leg exercise induce similar inflammatory responses. Medicine and Science in Sports and Exercise, 48 (6), pp. 1161-1168.Introduction: The amount of active muscle mass can influence the acute inflammatory response to exercise, associated with reduced risk for chronic disease. This may affect those restricted to upper body exercise, for example due to injury or disability. The purpose of this study was to compare the inflammatory responses for arm exercise and intensity-matched leg exercise. Methods: Twelve male individuals performed three 45-min constant load exercise trials following determination of peak oxygen uptake for arm exercise (V[Combining Dot Above]O2peak A) and cycling (V[Combining Dot Above]O2peak C): (1) arm cranking exercise at 60%V[Combining Dot Above]O2peak A; (2) moderate cycling at 60%V[Combining Dot Above]O2peak C; and (3) easy cycling at 60%V[Combining Dot Above]O2peak A. Cytokine, adrenaline and flow cytometric analysis of monocyte subsets were performed before and up to 4h post exercise. Results: Plasma IL-6 increased from resting concentrations in all trials, however, post exercise concentrations were higher for arm exercise (1.73+/-1.04pg[BULLET OPERATOR]mL-1) and moderate cycling (1.73+/-0.95pg[BULLET OPERATOR]mL-1) compared with easy cycling (0.87+/-0.41pg[BULLET OPERATOR]mL-1,P<0.04). Similarly, the plasma IL-1ra concentration in the recovery period was higher for arm exercise (325+/-139pg[BULLET OPERATOR]mL-1) and moderate cycling (316+/-128pg[BULLET OPERATOR]mL-1) when compared with easy cycling (245+/-77pg[BULLET OPERATOR]mL-1,P<0.04). Arm exercise and moderate cycling induced larger increases in monocyte numbers and larger increases of the classical monocyte subset in the recovery period than easy cycling (P<0.05). The post-exercise adrenaline concentration was lowest for easy cycling (P=0.04). Conclusions: Arm exercise and cycling at the same relative exercise intensity induces a comparable acute inflammatory response; however, cycling at the same absolute oxygen uptake as arm exercise results in a blunted cytokine, monocyte and adrenaline response. Relative exercise intensity appears to be more important to the acute inflammatory response than modality, which is of major relevance for populations restricted to upper body exercise