Decrease of DHEA-S concentration succeeding a micro-dose thumb exertion: Mood-state determinants reflect stress-biomarker responses

Background: The present study examined the effect of a micro-dose of resistance-exercise on serum DHEA-S, IL-6 and mood-state determinants. Potential relationships between mood and the biomarkers were also studied with the aim of directing research on non-invasive exercise-monitoring methods. Methods: 30 male participants (20 weightlifting-trained; 10 untrained) were separated into 3 groups of 10: weightlifting experimental (WLEXP); untrained experimental (UTEXP); weightlifting placebo (WLPLA). WLEXP and UTEXP performed four 60-s isometric thumb exertions separated by 60-s rest intervals in a single-blinded placebo-controlled study. Participants were assessed over a 60-min post-intervention recovery period for changes in serum DHEA-S and IL-6, and mood-state determinants (vigour, tension, fatigue). Results: DHEA-S changed in UTEXP only; a decrease from 20- to 60-min post-exercise (Δ36.9 %, p < 0.01). DHEA-S remained below baseline at the final time-point (Δ35.3 %, p = 0.012). Tension decreased immediately post-exercise in WLEXP (Δ86.7 %, p = 0.022), whereas UTEXP showed a delayed decrease which continued up to 60-min post-intervention (Δ100 %, p < 0.01). Relative to fatigue scores recorded immediately post-exercise, WLEXP decreased within the first 10-min post-intervention (Δ22.2 %, p < 0.01) whereas UTEXP showed a delayed decrease evident at 20-min post-intervention (Δ25 %, p < 0.01). Serum IL-6 and vigour scores remained unchanged across groups (p > 0.05) and WLPLA did not change for any measured variable (p > 0.05). Conclusions: The authors conclude that a micro-dose of resistance-exercise can reduce serological DHEA-S concentration within 60-min of exercise cessation. Additionally, mood-state assessment in untrained individuals can be considered for non-invasively indicating exercise-induced concentration changes in the stress biomarker, DHEA-S, providing prospects for the development of safer, more sophisticated exercise-monitoring practice.Griffith Health, School of Allied Health SciencesFull Tex

Isometric Thumb Exertion Induces B Cell and T Cell Lymphocytosis in Trained and Untrained Males: Physical Aptitude Determines Response Profiles

Purpose: The present study examined the effect of low-dose thumb exertion on lymphocyte subpopulation trafficking. The potential role of blood lactate in mediating lymphocyte redistribution was also investigated. Methods: 27 male participants (18 weightlifting-trained; 9 untrained) were separated into 3 groups of 9 (Weightlifting and Untrained Experimental: WLEXP, UTEXP; Weightlifting Placebo: WLPLA). WLEXP and UTEXP performed 4x60 second isometric thumb intervals separated by 60 second rest intervals in a single-blinded placebo-controlled study.  Participants were assessed over a 60 minute post-intervention recovery period for pain, blood lactate and lymphocyte subpopulation counts. Results: WLPLA did not change for any measured variable (p0.05). The two experimentalgroups increased significantly (p0.01) in thumb pain post-intervention (WLEXP:4.92/10; UTEXP:2.92/10) however only WLEXP remained elevated across all time-points. Blood lactate increased for both experimental groups post-intervention (p0.01) whilst peak concentrations (UTEXP: 2.2mmol/L; WLEXP: 2.4mmol/L) and temporal profiles were not different between groups (p0.05). No differences in cell count were seen for CD56+/CD16+ lymphocytes across time for any group (p0.05). UTEXP showed an early significant increase (20 min post-intervention) in CD4+CD3+ (20.78%, p0.01), CD8+CD3+ (15.25%, p0.01) and CD19+ (18.11%, p=0.013) cell count before returning to levels not different from baseline by the final time-point (p0.05). Conversely, WLEXP group showed no early increase followed by a delayed increase in cell count evident at the final time-point; CD4+CD3+ (19.06%, p0.01), CD8+CD3+ (11.46%, p=0.033) and CD19+ (28.87%, p0.01). Blood lactate was not correlated with lymphocyte counts. Conclusions: Physical aptitude and not cellular energy demand influences the lymphocyte response to resistance-exercise.Keywords: B-Lymphocytes; Exercise; Lactic Acid; Lymphocytosis; Resistance Training; T-Lymphocyte

Micro-dose of resistance-exercise:Effects of sub-maximal thumb exertion on leukocyte redistribution and fatigue in trained male weightlifters

This study examined the effect of a micro-dose of thumb resistance-exercise on leukocyte redistribution, thumb pinch-strength and reported fatigue. The effect of training status was also studied. 30 male participants (20 weightlifting-trained; 10 untrained) were separated into 3 groups of 10 (WLEXP; UTEXP; WLPLA) & performed 4 x60 second thumb isometric resistance-exercise intervals separated by 60 second rest intervals in a single-blinded placebo-controlled study. Participants were assessed over a 60 minute post-intervention recovery period. Pinch-strength decreased in WLEXP and UTEXP groups (p<0.01), and recovered to baseline values (p=0.01) in the WLEXP group only. Fatigue increased in WLEXP and UTEXP groups and remained elevated across time (p<0.01). Circulating total leukocyte and lymphocyte counts increased in WLEXP and UTEXP groups across time. Constant elevation was seen in both measures for the UTEXP group (p<0.05) whereas the WLEXP group showed two peaks in leukocyte (baseline – 0 mins post, p<0.01; 20 – 60 mins post, p=0.02) and lymphocyte counts (base-line – 0 mins post, p<0.01; 20 – 60 mins post, p<0.01). Monocyte count increased similarly from baseline (p=0.47) in the WLEXP group (p=0.02) and UTEXP group (p<0.01) at 60 minutes post. Our results suggest that perception of fatigue does not correlate with physiological recovery from thumb resistance-exercise in resistance-trained individuals which has implications for recovery monitoring. Of particular novelty, we also showed that a micro-dose of thumb resistance-exercise is sufficiently stressful to distort leukocyte trafficking and thus homeostasis.Griffith Health, School of Allied Health SciencesFull Tex

Isometric Thumb Exertion Induces B Cell and T Cell Lymphocytosis in Trained and Untrained Males: Physical Aptitude Determines Response Profiles

Purpose: The present study examined the effect of low-dose thumb exertion on lymphocyte subpopulation trafficking. The potential role of blood lactate in mediating lymphocyte redistribution was also investigated. Methods: 27 male participants (18 weightlifting-trained; 9 untrained) were separated into 3 groups of 9 (Weightlifting and Untrained Experimental: WLEXP, UTEXP; Weightlifting Placebo: WLPLA). WLEXP and UTEXP performed 4x60 second isometric thumb intervals separated by 60 second rest intervals in a single-blinded placebo-controlled study.  Participants were assessed over a 60 minute post-intervention recovery period for pain, blood lactate and lymphocyte subpopulation counts. Results: WLPLA did not change for any measured variable (p>0.05). The two experimentalgroups increased significantly (p0.05). No differences in cell count were seen for CD56+/CD16+ lymphocytes across time for any group (p>0.05). UTEXP showed an early significant increase (20 min post-intervention) in CD4+CD3+ (20.78%, p0.05). Conversely, WLEXP group showed no early increase followed by a delayed increase in cell count evident at the final time-point; CD4+CD3+ (19.06%, p<0.01), CD8+CD3+ (11.46%, p=0.033) and CD19+ (28.87%, p<0.01). Blood lactate was not correlated with lymphocyte counts. Conclusions: Physical aptitude and not cellular energy demand influences the lymphocyte response to resistance-exercise. Keywords: B-Lymphocytes; Exercise; Lactic Acid; Lymphocytosis; Resistance Training; T-Lymphocyte

Establishing a dose-response relationship between acute resistance-exercise and the immune system: Protocol for a systematic review

Exercise immunology research has traditionally focussed on aerobic-exercise, however it has become apparent in more recent years that resistance-exercise can also considerably affect host immunobiology. To date however, no systematic process has been used to establish a dose-response relationship between resistance-exercise and the immune system. The present systematic review was thus conducted to determine the dose-response effects of a bout of resistance-exercise on acute leukocyte counts. In accordance with the PRISMA guidelines, a systematic literature search was conducted in the electronic databases, PubMed, Web of Science, and Google Scholar, over the date range of 1989–2016. Following the PICO elements, eligibility criteria included: i) participants: healthy humans aged 18–40; ii) intervention: a single bout of resistance-exercise; iii) comparator: at least one comparator group; iv) outcome: acute measures of circulating leukocyte counts. Specific exclusion criteria were also applied. Risk of bias and quality of evidence was assessed using the PEDro scale. Due to the individual designs of the admitted studies, a qualitative analysis (systematic narrative synthesis) was employed in the present review. The results of the present review demonstrate that a single bout of resistance-exercise induces an acute monocytosis, neutrophilia, and lymphocytosis. It became apparent that the reviewed literature either does not consistently specify, or does not describe with sufficient detail, the time-course between the onset of exercise and the collection of blood. We recommend that researchers consider addressing this in future studies, and also collect blood measures during exercise to aid with comparison of temporal effects. Regarding the determination of a dose-response relationship, an acute neutrophilia, monocytosis and lymphocytosis appears to occur more rapidly and to a greater magnitude following a single bout of high-dose vs low-dose resistance-exercise. Mechanistically, exercise-induced cell trafficking changes are associated with mechanical, metabolic and endocrine factors. Physical aptitude of the host may also affect resistance-exercise-induced lymphocyte trafficking responses.No Full Tex