Reply to Drs. Pageaux et al.: Cognitive demand of eccentric versus concentric cycling.
J Appl Physiol (1985). 2017 Nov 01;123(5):1418
Authors: Nosaka K, Haynes A, Chasland LC, Maiorana A, Naylor LH, Green DJ
PMID: 29167208 [PubMed - in process]
Lower Resting and Exercise-Induced Circulating Angiogenic Progenitors and Angiogenic T-Cells in Older Men.
Am J Physiol Heart Circ Physiol. 2017 Nov 22;:ajpheart.00592.2017
Authors: Ross MD, Malone EM, Simpson R, Cranston I, Ingram L, Wright GP, Chambers G, Florida-James GD
Ageing is associated with a dysfunctional endothelial phenotype, as well as reduced angiogenic capabilities. Exercise exerts beneficial effects on the cardiovascular system, possibly by increasing/maintaining the number and/or function of circulating angiogenic cells (CACs) that are known to decline with age. However, the relationship between cardiorespiratory fitness (CRF) and age related changes in frequency of CACs, as well as the exercise-induced responsiveness of CACs in older individuals has not yet been determined. One hundred and seven healthy male volunteers, aged 18-75 years, participated in the study 1. CRF was estimated using submaximal cycling ergometer test. Circulating endothelial progenitor cells (EPCs), angiogenic T-cells (TANG) and their CXCR4 cell surface receptor expression were enumerated by flow cytometry using peripheral blood samples obtained under resting conditions prior to the exercise test. Study 2 recruited 17 healthy males (8 young, 18-25yrs; 9 older, 60-75yrs) and these participants undertook a 30-minute cycling exercise bout at 70% V ̇O2max, with CACs enumerated pre- and immediately post-exercise. Age was inversely associated with both CD34(+) progenitor cells (r2=-0.140, p=0.000) and TANG (r(2)=-0.176, p=0.000) cells, as well as CXCR4-expressing CACs (CD34(+), r(2)=-0.167, p=0.000; EPCs: r(2)=-0.098, p=0.001; TANG, r(2)=-0.053, p=0.015). However, after correcting for age, CRF had no relationship with either CAC subset. In addition, older individuals displayed attenuated exercise-induced increases in CD34(+) progenitor cells, TANG, CD4(+) TANG, and CD8(+)CXCR4(+) TANG cells. Older men display lower CAC levels, which may contribute to increased CVD risk, and older adults display an impaired exercise-induced responsiveness of these cells.
PMID: 29167123 [PubMed - as supplied by publisher]
Effect of 6 weeks of high-intensity one-legged cycling on functional sympatholysis and ATP signaling in patients with heart failure.
Am J Physiol Heart Circ Physiol. 2017 Nov 22;:ajpheart.00379.2017
Authors: Munch GW, Iepsen UW, Ryrsø CK, Rosenmeier JB, Pedersen BK, Mortensen SP
Breathlessness during daily activities is the primary symptom in patients with heart failure (HF). Poor correlation between the hemodynamic parameters of left ventricular performance and perceived symptoms suggests that other factors such as skeletal muscle function plays a role in determining exercise capacity. We investigated the effect of six weeks of high-intensity one-legged cycling (HIC; 8x4 at 90% one-legged cycling max) on: 1) the ability to override sympathetic vasoconstriction (arterial infusion of tyramine) during one-legged knee-extensor exercise (KEE); 2) vascular function (arterial infusion of ACh, SNP, tyramine and ATP); 3) exercise capacity in HF patients with reduced ejection fraction (n=8) compared with healthy individuals (n=6). Arterial tyramine infusion lowered leg blood flow and leg vascular conductance at rest and during KEE before the training intervention in both groups (P<0.05), but not during KEE after the training intervention. There was no difference between groups. The peak vasodilatory response to ATP was blunted in the HF patients. (P<0.05), whereas there was no difference in ACh- and SNP- induced vasodilation between HF patients and healthy individuals. ACh induced vasodilation increased in the HF patients after the training intervention (P<0.05). HIC improved aerobic capacity in both groups (P<0.05), whereas only the HF patients improved six min walking distance (P<0.05). These results suggest that exercise hyperemia and functional sympatholysis is not altered in HF patients, and that functional sympatholysis is improved with HIC in both HF patients and healthy individuals. Moreover, these results suggest that the peak vasodilatory response to ATP is blunted.
PMID: 29167117 [PubMed - as supplied by publisher]