Cerebral oxygenation and blood volume responses to seated whole-body vibration

Abstract

Role of backrest support and hand grip contractions on regional cerebral oxygenation and blood volume were evaluated by near infrared spectroscopy in 13 healthy men during whole-body vibration (WBV). Subjects were exposed to three WBV (3, 4.5, and 6 Hz at approximately 0.9 g(rms) in the vertical direction), in a randomized order on separate days. During WBV, subjects performed right-hand maximal voluntary intermittent rhythmic hand grip contractions for 1 min. Subjects demonstrated highest oxygenation and blood volume values at 4.5 Hz, however, these responses were similar with and without backrest support (P>0.01). Compared to WBV alone, addition of hand grip exercise during WBV further increased oxygenation (0.07+/-0.11 vs. 0.004+/-0.11 od, P=0.003) and blood volume (0.156+/-0.20 vs. 0.066+/-0.17 od, P=0.000) in the right forehead. Peak oxygen uptake did not correlate to changes in oxygenation and blood volume (P>0.01). Based on the increase in ventilation volume and no change in the ratio of ventilation volume and expired carbon dioxide (P>0.01), it is concluded that WBV induces hyperventilation that might activate the pre-frontal cortical region, thus influencing cerebral responses through neuronal activation.

Assessment of cerebral oxygenation during prolonged simulated driving using near infrared spectroscopy: its implications for fatigue development

“…Comparison of reaction time between the Task group and CNL during the post-task period, p < 0.05 Hirth et al 1997;Maikala et al 2005). The reduction in the cerebral oxygenation and total blood volume indicated a reduction in blood Xow to the brain at the end of the simulated driving task.…”

“…An important parameter of brain oxygen supply is cerebral oxygen saturation, which indicates the proportion of oxygenated blood in the microcirculation and measures the oxygen available in the capillary circulation (Harrison et al 1992). Cerebral oxygen saturation can be assessed with near infrared spectroscopy (NIRS) (Simonson and Piantidosi 1996;Maikala et al 2005;Teng et al 2006a, b;Tachtsidis et al 2008a, b;Thomas and Stephane 2008).…”

“…The relative change in oxyHb saturation at the arterioles, capillaries and venules can be evaluated by the diVerence in absorbency between these two wavelengths, whereas the sum of the absorbencies indicates the relative change in localized blood volume (Bhambhani et al 2007). The NIRS has been widely used in evaluating changes in cerebral oxygenation and blood volume under a variety of experimental conditions such as jugular bulb venous oxygen saturation (Pollard et al 1996) and exposure to whole-body vibration (Maikala et al 2005(Maikala et al , 2006Maikala and Bhambhani 2008).…”

Functional changes in cerebral and paraspinal muscle physiology of healthy women during exposure to whole-body vibration

“…Details of the vibrating base, and the seat with backrest support, were discussed elsewhere (Maikala et al, 2005. Briefly, a Work Seat TM (Model WS-40, Advanced Therapy Products, Inc., USA), with an internal spring-suspension system and a weight-adjustable knob, was bolted to the vibrating base assembly.…”

“…and localized tissue responses (cerebral and lumbar muscle oxygenation and blood volume) in healthy men. Using near-infrared spectroscopy (NIRS), Maikala et al (2005) demonstrated an increase in cerebral oxygenation and blood volume as a function of the WBV-related factors, implying greater neuronal activation compared to without WBV. In the same participants, showed a decrease in the lumbar erector spinae oxygenation and blood volume trends with a simultaneous increase in cardiorespiratory responses , confirming the much speculated hypothesis of the deficiency in the blood supply to lumbar muscles due to exposure to occupational WBV (Hansson et al, 1991).…”