Role of skeletal muscles impairment and brain oxygenation in limiting oxidative metabolism during exercise after bed rest

"Central" and "peripheral" limitations to oxidative metabolism during exercise were evaluated in 10 young males following a 35-day horizontal bed rest (BR). Incremental exercise (IE) and moderate- and heavy-intensity constant-load exercises (CLE) …

A Dynamic Objective Evaluation of Peripheral Arterial Disease by Near-Infrared Spectroscopy

Objectives: Near-Infrared Spectroscopy (NIRS), suitable for dynamic measurements, is not routinely used for peripheral arterial disease (PAD). We propose a dynamic NIRS-based measurement to quantify variations in muscle metabolism in PAD. Method: …

Effect of prior exercise on pulmonary O2 uptake and estimated muscle capillary blood flow kinetics during moderate-intensity field running in men

The effect of prior exercise on pulmonary O2 uptake (V̇O2 p) and estimated muscle capillary blood flow (Q̇m) kinetics during moderate-intensity, field-based running was examined in 14 young adult men, presenting with either moderately fast (16 s

Changes in cerebral oxygenation and hemodynamics during cranial ultrasound in preterm infants

Objectives: To evaluate whether application of a transducer on the anterior fontanelle during cranial ultrasound (US) examination effects cerebral hemodynamics and oxygenation in preterm infants. Study design*: During cranial US examination, changes …

Frontal and motor cortex oxygenation during maximal exercise in normoxia and hypoxia

Reductions in prefrontal oxygenation near maximal exertion may limit exercise performance by impairing executive functions that influence the decision to stop exercising; however, whether deoxygenation also occurs in motor regions that more directly …

Effect of ventilation on cerebral oxygenation during exercise: Insights from canonical correlation

We tested hypothesis that cerebral deoxygenation near maximal exercise intensity is mediated by hyperventilation, via hypocapnia-induced reductions in cerebral blood flow, by utilizing canonical correlation analysis (CCA) to determine the relative …

Energy metabolism in human calf muscle performing isometric plantar flexion superimposed by 20-Hz vibration

Vibration training is commonly expected to induce an active muscle contraction via a complex reflex mechanism. In calf muscles of 20 untrained subjects, the additional energy consumption in response to vibration superimposed on an isometric …

Low-level activity of the trunk extensor muscles causes electromyographic manifestations of fatigue in absence of decreased oxygenation

This study was designed to determine whether trunk extensor fatigue occurs during low-level activity and whether this is associated with a drop in muscle tissue oxygenation. Electromyography (EMG) feedback was used to impose constant activity in a …

NIRS-SPM: Statistical parametric mapping for near-infrared spectroscopy

Near infrared spectroscopy (NIRS) is a non-invasive method to measure brain activity via changes in the degree of hemoglobin oxygenation through the intact skull. As optically measured hemoglobin signals strongly correlate with BOLD signals, …

General linear model and inference for near infrared spectroscopy using global confidence region analysis

Near infared spectroscopy (NIRS) is a non-invasive method to measure the brain activity as the changes of hemoglobin oxygenation through the intact skull. In this paper, we statistically analyze the NIRS data based on general linear model (GLM) and …

Cerebrovascular responses to incremental exercise during hypobaric hypoxia: Effect of oxygenation on maximal performance

We sought to describe cerebrovascular responses to incremental exercise and test the hypothesis that changes in cerebral oxygenation influence maximal performance. Eleven men cycled in three conditions: 1) sea level (SL); 2) acute hypoxia [AH; …

Near-infrared spectroscopy extended with indocyanine green dye dilution for cerebral blood flow measurement: Median values in healthy volunteers

The cerebral blood flow (CBF) is an important vital parameter in neurointensive care. Currently, there is no non-invasive method for its measurement that can easily be applied at the bedside. A new tool to determine CBF is based on near-infrared …

Cerebral hemodynamics and oxygenation after serial CSF drainage in infants with PHVD

The aim of our study was to assess consecutive changes in cerebral oxygenation and hemodynamics after serial cerebrospinal fluid (CSF) drainage from a subcutaneous ventricular catheter reservoir (SVCR) in infants with PHVD. Infants with PHVD were …

Effect of short recovery intensities on the performance during two Wingate tests

PURPOSE: To assess the effects of the intensity of short recoveries on performance by a Wingate test and on the deoxyhemoglobin variations. METHODS: Twelve male subjects performed a graded test and three sessions of repeated all-out tests with …

Effects of acute hypoxia on cerebral and muscle oxygenation during incremental exercise

To determine if fatigue at maximal aerobic power output was associated with a critical decrease in cerebral oxygenation, 13 male cyclists performed incremental maximal exercise tests (25 W/min ramp) under normoxic (Norm: 21% FIO2) and acute hypoxic …

Effects of rapid versus slow infusion of sodium bicarbonate on cerebral hemodynamics and oxygenation in preterm infants

Background: Sodium bicarbonate (NaHCO3) is often used for correction of metabolic acidosis in preterm infants. The effects of NaHCO 3 administration on cerebral hemodynamics and oxygenation are not well known. Furthermore, there is no consensus on …

Brain cell function during hypoxemia in near-term lambs: A near-infrared spectroscopy study

Background: Sufficient O2 supply to the brain is necessary for adequate cerebral energy metabolism, function and growth. Objectives: To elucidate the relation between changes in cerebral arterial O2 content and cerebral O2 supply and changes in the …

Transcranial oximetry using fast near infrared spectroscopy can detect failure of collateral blood supply in humans

We tested the hypothesis that transcranial oximetry by fast scanning near infrared spectroscopy can detect local desaturation of hemoglobin in arterial vessels of cerebral circulation with impaired blood supply. A total of 74 near infrared …

Experimental verification of conditions for near infrared spectroscopy (NIRS)

Objectives: in vitro assessment of the reproducibility and the optimal separation and position of the optodes in continuous wave (CW-) NIRS measurement of local inhomogeneities in absorption and/or scattering. Methods: a CW- NIRS system (OXYMON) was …

Simultaneous measurements of cerebral oxygenation changes during brain activation by near-infrared spectroscopy and functional magnetic resonance imaging in healthy young and elderly subjects

Near infrared spectroscopy (NIRS) and functional magnetic resonance imaging (fMRI) both allow non-invasive monitoring of cerebral cortical oxygenation responses to various stimuli. To compare these methods in elderly subjects and to determine the …