Research Paper Volume 14, Issue 9 pp 3910—3920

Figure 3. Scatter plots of BOV and BHV during a maximal handgrip strength test of 834 adults aged 20–88 y. The 30-sec handgrip test includes a 10-repeated voluntary maximal exertion on a dynamometer with 3-sec rest intervals. BOV values (A–C) are calculated as standard deviation of oxygen saturation values during the 3 phases: a 30-sec rest (300 values), a 30-sec contraction (300 values), and a 30-sec recovery (300 values). Similarly, BHV values (D–F) are calculated as SD of total hemoglobin values during the 3 phases (rest, contraction, recovery). A sharp elevation of BHV after age 50 y was apparent for >80% of adults, similar for men (G) and women (H) during voluntary muscle exertions at maximal effort. Abbreviations: SD: standard deviation of the 300 optical data in 30 sec; BOV: brain oxygenation variability; BHV: brain hemodynamic variability.