Abstract details
| Abstract-ID: | 1887 |
| Title of the paper: | The effect of aging and training on skeletal muscle basal metabolism and microvasculature health as revealed by non-invasive in-vivo time-domain near infrared spectroscopy |
| Authors: | Re, R., Contini L., Nabacino M., Contini D., Amendola C., Spinelli L., Botter A., Franchi M., Alcazar J., Lauretani F., Porcelli S., Torricelli A. |
| Institution: | Politecnico di Milano |
| Department: | Department of Physics |
| Country: | Italy |
| Abstract text | INTRODUCTION: Training and aging cause modifications in skeletal muscle. Their combined effect is still under debate. We estimate oxidative metabolism and microvasculature health by time-domain (TD) near infrared spectroscopy (NIRS). We preliminary measured the absolute values of oxy- (O2Hb), deoxy- (HHb), total- (tHb) hemoglobin concentration, and tissue oxygen saturation (StO2). Then, we studied distinct vascular control mechanisms exploiting spontaneous oscillations of the hemodynamic parameters in peculiar frequency bands: Endothelial (VI: <0.0095 Hz), NO-related Endothelial (V: 0.0095-0.021 Hz), Neurogenic (IV: 0.021-0.052 Hz) and Myogenic (III: 0.052-0.145 Hz). METHODS: We studied 4 different subjects groups: 1) 15 Old Trained (OT), 72±5 y, master athletes competing in running or cycling and following high-intensity weekly training; 2) 6 Old Untrained (OU), 78±5 y, minimal physical activity, assessed by step-counters; 3) 15 Young trained (YT), 24±3 y, competitive sprinters following high-intensity daily training; 4) 15 Young Untrained (YU), 27±4 y, moderate physical activity without structured training. TD-NIRS acquisitions were performed on the vastus lateralis (VL) muscle of the dominant leg during 300 s at rest, exploiting a portable device (PIONIRS s.r.l., Italy) with 2.5 cm source-detector distance. Absolute values for the concentrations of O2Hb, HHb, tHb and StO2 on VL were calculated and the relative power spectral density (rPSD), for all the parameters, inside bands III-VI were found. Statistically significant differences between groups were identified using Mann-Whitney U tests with correction for multiple comparisons. RESULTS: Basal O2Hb was higher for YT = 100±26 µM vs YU = 738±28 µM, p = 0.029, and OU = 64±22, p = 0.004, but not vs OT = 78±27 µM, p = 0.076, suggesting that training improves perfusion during rest, regardless of aging. Similar results were obtained for tHb. HHb had higher values only for YT (49±17 µM) vs YU (32±1 µM, p = 0.025), showing that venous compartment in the VL muscle is less sensitive to aging and training. StO2 is significantly different among all groups except for YT (68±3 %) vs YU (70±35 %, p = 0.073) and OT (66±4 %, p = 0.109). The StO2 values found for all groups and their differences confirm the effect of aging on muscle oxidative basal metabolism. For rPSD we found that: 1) Bands VI and V: most of the parameters have higher values for OT vs OU and YT vs YU (pmax=0.04), underlying the role of endothelial activity as a marker of microvascular health and adaptability; 2) Bands IV and III: opposite pattern observed, in particular for OT vs OU (pmin=0.07). CONCLUSION: TD-NIRS has the potential to be a useful tool for monitoring early signs of aging-related decline and muscular training effect. Training is more impactful than aging on muscle microvasculature health and basal metabolism. The more trained muscles rely less on autonomic or smooth-muscle-mediated components, underlying the role of endothelial activity as a biomarker of trained muscles. |
| Topic: | Health and Fitness |
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