News & Views from the Editor-in-Chief: Andrew M. Jones
.jpg)
The health and performance benefits of increased physical activity or structured exercise training is of substantial interest to the readership of MSSE. Not surprisingly, the journal receives many submissions which provide insight into the mechanisms underpinning physiological adaptations to exercise and which may enable the development of patterns of activity or training which optimize health or performance outcomes. This month I have highlighted three articles which contribute to understanding in this important area.
A key question remains regarding the mechanisms that control cardiovascular and metabolic adaptations to endurance exercise training: to which stimuli are the systems adapting? It seems difficult to explain mechanisms if the metabolic stimulus determining adaptations is not adequately controlled at the individual level. Ingles and colleagues' study, “Changes in V̇O2max after 6 Weeks of Intensity Domain-Specific Training: Role of Central and Peripheral Adaptations," was the first to apply the full intensity domain spectrum (from moderate to extreme) to investigate the domain-specific central and peripheral contributions to increase V̇O2max in young untrained females and males. After 6 weeks of cycling training (18 sessions): i) increases in V̇O2max were intensity domain-dependent, with severe- and upper heavy-intensity training being the most effective, and moderate intensity exercise showing no significant changes; ii) both central (Q̇max, SVmax, and hematological variables) and peripheral (diffusive O2 conductance) adaptations contributed to training-induced changes in V̇O2max.
A key innovative contribution of van der Sluijs, Bakker and colleagues' article entitled “Cardiometabolic Benefit of Replacing Sedentary Time with Light-Intensity Physical Activity: Compositional Data Analysis of the Nijmegen Exercise Study" was the focus on replacing sedentary time (ST) with light-intensity physical activity (LIPA). Their findings suggest that replacing ST with LIPA may significantly improve anthropometrics and glucose metabolism. Importantly, the greatest benefits may be obtained by those who are most sedentary and, therefore, might be the most at risk of cardiovascular disease. Another key finding is that proportionally similar replacements of ST to either LIPA or moderate-to-vigorous physical activity (MVPA) (i.e., around 10% increase) could result in similar cardiometabolic improvements. This highlights the magnitude of benefits that performance of LIPA may offer. Since engaging in LIPA is feasible and relatively easy to incorporate into daily routines for most of the population, replacing ST with LIPA could be considered an effective strategy to improve population-wide cardiometabolic health.
Hemodynamic forces represent the forces exchanged between the blood and the surrounding tissue that propel the blood out of the left ventricle and these have been recently proposed as a new parameter of cardiac function. In “Effects of Intense Physical Training on Left Ventricular Hemodynamic Forces in Endurance Athletes: A Feature-Tracking Cardiac Magnetic Resonance Study," Rakhmanov and colleagues evaluated 40 endurance athletes at the beginning of their training cycle (off-season) and after a period of aerobic isotonic dynamic exercise (peak training period) using cardiac magnetic resonance. Hemodynamic forces parameters for the whole cardiac cycle and the different cardiac phases were evaluated. The results did not show differences in cardiac geometry or deformation imaging; however, physical training induced a significant increase in the hemodynamic forces throughout the entire heartbeat and in the first part of systole. This study opens new avenues for assessing the cardiac performance and the effect of physical training in endurance athletes.
Andrew M. Jones
University of Exeter
