Browsing by Author "Florindo, Margarida"
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- Lower limb dynamic activity significantly reduces foot skin perfusion: exploring data with different optical sensors in age-grouped healthy adultsPublication . Florindo, Margarida; Nuno, Sérgio Loureiro; Rodrigues, Luis MonteiroIntroduction: The human lower limb is widely used as a model to study in vivo microcirculatory physiology and pathophysiology. It is a preferential target for critical comorbidities (overweight, diabetes, and peripheral vascular disease). Movement and activity are consistently regarded as beneficial, but the related adaptive physiology is still poorly understood. Our goal was to better identify the foot microcirculatory changes after a regular walking gait activity in healthy subjects of different ages. Methods: Twelve healthy participants of both sexes, with normal BMI and Ankle-Brachial Index, were selected and grouped according to age - group I (21.0 ± 1 y.o.) and group II (55.8 ± 3 y.o.). The protocol involved 2 phases of 5-min duration each - phase 1, a static standing position, and phase 2, 5-min walking with a comfortable pace on a pre-established circuit. Perfusion changes were assessed in the dorsal region of both feet before (baseline, phase 1) and after (phase 2) the gait period by noninvasive optical technologies - laser Doppler flowmetry (LDF), photoplethysmography, and polarized spectroscopy (PSp). Comparative statistics were performed with a 95% confidence level. Results: All instruments detected asymmetric nonsignificant perfusion between right and left feet during rest in all participants with values in females consistently lower than men. Older participants exhibited lower baseline values than the younger group. Gait evoked a perfusion reduction in all participants relative to phase 1 detected with all technologies, with statistically significant changes recorded with LDF (group I, p = 0.033, and group II, p = 0.028) and PSp (group II, p = 0.041). Furthermore, LDF revealed that gait significantly reduced perfusion velocity in the older group (p = 0.003). Corresponding changes in the younger group were present but discrete. Recovery to baseline levels was also slower in the older group. Discussion/Conclusions: Our results confirm that perfusion is age-dependent and demonstrate the clinical relevance of simple dynamic activities such as gait. This reduction of the dorsal foot perfusion occurs in-depth, being more pronounced with the movement intensity, suggesting a wide application potential in early diagnostics as for rehabilitation.
- Studying the impact of different body positioning, squatting, and unipodal flexion on perfusion in the lower limb: an exploratory approach complemented with optical spectroscopy (TiVi)Publication . Nuno, Sérgio; Florindo, Margarida; Silva, Henrique; Rodrigues, Luis MonteiroBody posture and movement seem to be responsible for multiple variations of microcirculation in the foot, although difficulties associated with measurement during movement have limited their characterization. This pilot study sought to explore a new non-invasive instrument based on polarized light spectroscopy – the TiVi system, under orthostatic and dynamic conditions. Five healthy participants (duly informed, 26.0 ± 6.5 years of age) of both genders were selected. The protocol involved sequential posture changes (orthostatic variation) and dynamic movements (squatting and unipodal flexion). Perfusion variations were evaluated in both feet by laser-Doppler flowmetry (LDF) and polarized spectroscopy (TiVi). Both systems revealed the same type of modification of these flow-related variables. The most pronounced changes were obtained with exercise, especially with squatting, which caused a marked increase in foot perfusion. Less dramatic but in the same direction, the increased perfusion with unipodal flexion was also observed in the contralateral limb. This study confirmed the interest in using the TiVi system in these domains, as well as the appropriateness of this experimental design to look deeper into the impact of lower limb movement on the functional dynamics of the foot.