Postexercise hypotension and related hemodynamic responses to cycling under heat stress in untrained men with elevated blood pressure

Purpose: To investigate the effect of heat stress on postexercise hypotension. Methods: Seven untrained men, aged 21–33 years, performed two cycling bouts at 60% of oxygen uptake reserve expending 300 kcal in environmental temperatures of 21 °C (TEMP) and 35 °C (HOT) in a randomized, counter-balanced order. Physiological responses were monitored for 10-min before and 60-min after each exercise bout, and after a non-exercise control session (CON). Blood pressure (BP) also was measured during the subsequent 21-h recovery period. Results: Compared to CON, systolic, and diastolic BPs were significantly reduced in HOT (Δ = − 8.3 ± 1.6 and − 9.7 ± 1.4 mmHg, P &lt; 0.01) and TEMP (Δ = − 4.9 ± 2.1 and − 4.5 ± 0.9 mmHg, P &lt; 0.05) during the first 60 min of postexercise recovery. Compared to TEMP, rectal temperature was 0.6 °C higher (P = 0.001), mean skin temperature was 1.8 °C higher (P = 0.013), and plasma volume (PV) was 2.6 percentage points lower (P = 0.005) in HOT. During the subsequent 21-h recovery period systolic BP was 4.2 mmHg lower in HOT compared to CON (P = 0.016) and 2.5 mmHg lower in HOT compared to TEMP (P = 0.039). Conclusion: Exercise in the heat increases the hypotensive effects of exercise for at least 22 h in untrained men with elevated blood pressure. Our findings indicate that augmented core and skin temperatures and decreased PV are the main hemodynamic mechanisms underlying a reduction in BP after exercise performed under heat stress.</p

Using Behavior Change Interventions in Cardiac and Pulmonary Rehabilitation: Perspectives from Healthcare Professionals in the United Kingdom

This study explores healthcare professionals’ experiences of using behavior change interventions in clinical practice. Semi-structured qualitative interviews were conducted with 11 healthcare professionals working in a cardiac and pulmonary rehabilitation National Health Service Trust in the United Kingdom. Interviews were transcribed and analyzed using inductive thematic analysis. Four overarching themes representing healthcare practitioners’ perceptions of using behavior change interventions were identified: (1) reliance on experiential learning, (2) knowledge transition, (3) existing professional development programs, and (4) barriers and facilitators for continued professional development. The results are discussed in relation to the implications they may have for behavior change training in clinical healthcare practice. Healthcare professionals require bespoke and formalized training to optimize their delivery of behavior change interventions in cardiac and pulmonary rehabilitation. Doing so will enhance intervention fidelity and implementation that can potentially ameliorate patient rehabilitation outcomes

Reproducibility of measurement techniques used for creatine kinase, interleukin-6 and high-sensitivity C-reactive protein determination over a 48 h period in males and females

To examine the reproducibility of three measurement techniques used to determine creatine kinase, interleukin-6 and high-sensitivity C-reactive protein, 50 participants had blood samples taken on two occasions. Fingertip plasma samples were analysed using the Reflotron for CK determination. Venous blood samples collected into serum separator tubes were used for IL-6 and hs-CRP analyses. IL-6 was measured using an enzyme linked immune assay development kit. The hs-CRP was measured by an in-house ELISA method. Dependent t-tests showed no systematic bias between samples. The interdian CV was 20.0% for CK, 15.3% for IL-6 and 44.2% for hs-CRP. The intraclass correlation coefficient was 0.90 for CK, 0.98 for IL-6 and 0.70 for hs-CRP. The 95% limits of agreement were ?69.7 to 63.5 IU/L for CK, ?1.48 to 1.80?pg/ml for IL-6 and ?1.10 to 0.91??g/L for hs-CRP. The results demonstrate low absolute reproducibility, which may obscure a true experimental effect. ? 2018, ? 2018 Taylor & Francis.Association of Anaesthetists of Great Britain and Ireland, University of Western Sydney, Aspetar Orthopaedic and Sports Medicine Hospital, Central Manchester University Hospitals NHS Foundation Trust, Loughborough University, College of Arts and Sciences, Boston University, University of Hul

Hypoxia mediated release of endothelial microparticles and increased association of S100A12 with circulating neutrophils

Microparticles are released from the endothelium under normal homeostatic conditions and have been shown elevated in disease states, most notably those characterised by endothelial dysfunction. The endothelium is sensitive to oxidative stress/status and vascular cell adhesion molecule-1 (VCAM-1) expression is upregulated upon activated endothelium, furthermore the presence of VCAM-1 on microparticles is known. S100A12, a calcium binding protein part of the S100 family, is shown to be present on circulating leukocytes and is thought a sensitive marker to local inflammatory process, which may be driven by oxidative stress. Eight healthy males were subjected to breathing hypoxic air (15% O2, approximately equivalent to 3000 metres altitude) for 80 minutes in a temperature controlled laboratory and venous blood samples were processed immediately for VCAM-1 microparticles (VCAM-1 MP) and S100A12 association with leukocytes by flow cytometry. A pre-hypoxic blood sample was used for comparison. Both VCAM-1 MP and S100A12 association with neutrophils were significantly elevated post hypoxic breathing later declining to levels observed in the pre-test samples. A similar trend was observed in both cases and a correlation may exist between these two markers in response to hypoxia. These data offer evidence using novel markers of endothelial and circulating blood responses to hypoxia

Standardized MET value underestimates the energy cost of treadmill running in men

AbstractThe main purpose of the present study was to compare the reference metabolic equivalent (MET) value and observed resting oxygen uptake (VO2) for defining cardiorespiratory fitness (VO2max) and characterizing the energy cost of treadmill running. A heterogeneous cohort of 114 healthy men volunteered to participate. In Part 1 of the study, 114 men [mean±SD, age: 24±5 years; height: 177.1±7.9 cm; body mass: 75.0±10.0 kg] visited the laboratory twice for assessment of resting and maximal VO2 values to compare the reference MET value vs. observed resting VO2 and to investigate the association between resting VO2 and VO2max. In Part 2, 14 of the 114 men visited the laboratory once more to perform a 30-min bout of running at 8.0 km∙h−1/8.3 METs. The mean observed resting VO2 of 3.26 mL·kg−1·min−1 was lower than the reference MET value of 3.5 mL·kg−1·min−1 (P&lt;0.001). Resting and maximal VO2 values relative to total body mass and fat-free mass were positively correlated (R=0.71 and 0.60, respectively; P&lt;0.001). The maximal MET and energy cost of treadmill running were consequently underestimated when calculated using the reference MET value only for those with low VO2max (P=0.005 to P&lt;0.001). In conclusion, the reference MET value considerably overestimated observed resting VO2 in men with low VO2max, resulting in underestimations of the maximal MET, exercise intensity prescription, and the energy cost of running.</jats:p