The influence of cardiovascular risk factors on near-infrared spectroscopy-derived muscle oxygen saturation during exercise recovery in older adults


Purpose Aging is typically accompanied by risk for cardiovascular disease (CVD), which both are associated with reduced muscle oxygen saturation (SmO2) during exercise recovery. However, the apart impact of aging and CVD risk factors on muscle reoxygenation parameters during exercise recovery have not been addressed yet. Methods Twenty healthy young individuals (34 ± 11 years), 20 older adults free from (67 ± 4 years), and 25 others at risk for CVD (67 ± 5 years) participated in the study. Near-infrared spectroscopy was utilized to evaluate forearm muscle oxygen saturation during handgrip exercise performed at 30% maximal voluntary contraction. Participants performed one set of rhythmic handgrip exercises until fatigue following 2 min of recovery. The oxygen resaturation rate during exercise recovery (SmO2RR) was calculated as the linear upslope of the SmO2 value over the first 5 s immediately following exercise. Results SmO2RR was significantly faster in healthy young as compared to older adults free from CVD (P = 0.027, d = 0.69) and older adults at risk for CVD (P textless 0.001, d = 1.25), with moderate to very large effect size. No significant difference in SmO2RR between the older adults group (P = 0.226) was observed, despite a large effect size (d = 0.87). Conclusion The findings of the current study demonstrated that aging, independently of the presence of CVD risk factors, negatively affects muscle oxygen resaturation after exercise. However, the effect of CVD risk factors on muscle SmO2 following exercise should not be neglected.

Sport Sciences for Health