The effects of aging and cardiovascular risk factors on microvascular function assessed by near-infrared spectroscopy

This study aimed to evaluate whether NIRS-derived reperfusion rate would detect potential differences in the forearm microvascular responsiveness between young healthy adults, and older adults free from or with cardiovascular disease (CVD) risk factors. Fifteen healthy young (age: 24.8 ± 4.0 years), seventeen older adults free of CVD risk factors (age: 67.0 ± 6.8 years), and twenty-three older adults with CVD risk factors (age: 67.9 ± 8.0 years) participated this study. Individuals underwent a blood draw and vascular occlusion test (30 s of baseline, 5 min of occlusion, and 2 min of reperfusion) and microvascular responsiveness was evaluated by using NIRS-derived tissue oxygen saturation indexes during reperfusion. A significant slower reperfusion rate and lower reperfusion magnitude was observed in older adults with CVD risk factors compared to healthy young and older adults. Although no statistical differences were found between healthy young and older individuals, there was a small (d = 0.4) effect size for reperfusion rate and moderate (d = 0.7) effects size for reperfusion magnitude when comparing these groups. In conclusion, this study demonstrated that even though the effects of aging per se on microvascular function should not be completely neglected, the CVD risk factors seem to be determinant on microvascular responsiveness impairment associated with aging.