near infrared spectroscopy muscle oxygen

OBJECTIVE: Previous research has primarily focused on the association between muscle strength and global cognitive function in older adults, while the connection between muscle strength and advanced cognitive function such as inhibition and working memory (WM) remains unclear. This study aimed to investigate the relationship among muscle strength, WM, and task-related cortex hemodynamics. METHODS: We recruited eighty-one older adults. Muscle strength was measured using a grip and lower limb strength protocol...

BACKGROUND: Unilateral diaphragm dysfunction (UDD) is an underdiagnosed cause of dyspnoea. Inspiratory muscle training (IMT) is the only conservative treatment for UDD, but the mechanisms of improvement are unknown. We characterised the effects of IMT on dyspnoea, exercise tolerance and respiratory muscle function in people with UDD. METHODS: 15 people with UDD (73% male, 61±8 years) were randomised to 6 months of IMT (50% maximal inspiratory mouth pressure ( P I,max ), n=10) or sham training (10% P I,max , n=5) (30 breaths twice per day)...

We investigated the relationship of the time-dependent behaviour of muscle oxygen saturation SmO2 (t), phosphagen energy supply WPCr (t) and blood lactate accumulation ΔBLC(t) during a 60-s all-out cycling sprint and tested SmO2 (t) for correlations with the end of the fatigue-free state tFf , maximal pedalling rate PRmax and maximal blood lactate accumulation rate v̇Lamax . Nine male elite track cyclists performed four maximal sprints (3, 8, 12, 60 s) on a cycle ergometer. Crank force and cadence were monitored continuously to determine PRmax and tFf based on force-velocity profiles...

We developed a multidistance and multiwavelength continuous wave NIRS instrument to detect dynamic changes in oxygenated and deoxygenated hemoglobin (oxy- and deoxy-Hb), oxidized cytochrome-c-oxidase (oxCCO) and water of the brain and muscle. We performed measurements of the forehead during resting state and paced breathing and of the forearm during ischemic challenge in human adults. Time series analysis focusing on rhythmic signals over different time scales and different depths of the tissue revealed specific patterns of phase relationships among the signals in each of the measurement...

The aim of this study was to investigate the longitudinal relationship between the slopes of systemic and quadriceps muscle O2 dynamics in subjects without attenuation point in deoxygenated hemoglobin concentration at vastus lateralis (APdeoxy-Hb@VL ) during high-intensity cycling. Seven young men without APdeoxy-Hb@VL performed ramp cycling exercise until exhaustion before and after 8 weeks, while continuing recreational physical activities throughout that period. Muscle O2 saturation (SmO2 ) and deoxy-Hb were monitored at the vastus lateralis (VL) and rectus femoris (RF) by near infrared spectroscopy oximetry during exercise...

Long periods of bed rest for elderly population, due to a femur fracture event, can cause a deterioration in the muscular capacity. Therefore, monitoring of the muscle oxidative capacity in this fragile population is necessary to define the muscular oxidative metabolism state before and after a rehabilitation period. The time-domain near-infrared spectroscopy (TD-NIRS) technique enables the absolute values to be calculated for hemodynamic parameters such as oxy- (O2 Hb), deoxy- (HHb), total- (tHb) haemoglobin, and tissue oxygen saturation (SO2 ) of the muscular tissue...

Background: Respiratory muscle training (RMT) has been investigated in the context of improved athletic performance and pulmonary function. However, psychophysiological costs of RMT remain understudied. Voluntary isocapnic hyperpnoea (VIH) and inspiratory pressure threshold loading (IPTL) are widely applied RMT methods. The main purposes of this study were to assess whether RMT induces additional load on well-trained triathletes and determine differences in RMT-induced load between sexes and applied methods...

BACKGROUND: Near-infrared spectroscopy (NIRS) provides regional tissue oxygenation (rSO2 ) even in pulseless states, such as out-of-hospital cardiac arrest (OHCA). Brain rSO2 seems to be important predictor of return of spontaneous circulation (ROSC) during cardiopulmonary resuscitation (CPR). Aim of our study was to explore feasibility for monitoring and detecting changes of skeletal muscle rSO2 during resuscitation. METHODS: Skeletal muscle and brain rSO2 were measured by NIRS (SenSmart Model X-100, Nonin, USA) during CPR in adult patient with OHCA...

Cardiopulmonary exercise test (CPET) is a valuable diagnostic tool with a specific application in heart failure (HF) thanks to the strong prognostic value of its parameters. The most important value provided by CPET is the peak oxygen uptake (peak VO2), the maximum rate of oxygen consumption attainable during physical exertion. According to the Fick principle, VO2 equals cardiac output (Qc) times the arteriovenous content difference [C(a-v)O2], where Ca is the arterial oxygen and Cv is the mixed venous oxygen content, respectively; therefore, VO2 can be reduced both by impaired O2 delivery (reduced Qc) or extraction (reduced arteriovenous O2 content)...

Minimally invasive staged segmental artery coil embolization (MIS2 ACE) is an emerging technology for priming of the paraspinous collateral network prior to open or endovascular thoracoabdominal aortic aneurysm (TAAA) repair. Its safety and efficacy have been previously proven in various experimental settings and confirmed in numerous multicentric pilot studies for open and endovascular repair. MIS2 ACE is safe and has the potential to decisively reduce the risk of postoperative paraplegia, the most devastating complication of open and endovascular TAAA repair, still affecting up to 20% of patients...

Fleitas-Paniagua, PR, de Almeida Azevedo, R, Trpcic, M, Murias, JM, and Rogers, B. Combining near-infrared spectroscopy and heart rate variability derived thresholds to estimate the critical intensity of exercise. J Strength Cond Res XX(X): 000-000, 2023-Critical intensity determination often requires costly tools and several testing sessions. Alternative approaches display relatively large individual variation. Therefore, simpler estimations with improved precision are needed. This study evaluated whether averaging the heart rate (HR) and oxygen uptake (V̇O2) responses associated with the muscle deoxyhemoglobin concentration breakpoint ([HHb]BP) and the heart rate variability (HRV) given by the detrended fluctuation analysis second threshold (HRVT2) during ramp incremental (RI) test improved the accuracy of identifying the HR and V̇O2 at the respiratory compensation point (RCP)...

Shoemaker, ME, Smith, CM, Gillen, ZM, and Cramer, JT. Sex differences in test-retest reliability of near-infrared spectroscopy during postocclusive reactive hyperemia of the vastus lateralis. J Strength Cond Res XX(X): 000-000, 2023-The purpose of this study was to determine test-retest reliability for vascular reactivity measures and ranges for normalization of near-infrared spectroscopy (NIRS) variables from the vastus lateralis using postocclusive reactive hyperemia (PORH) procedure in male subjects, female subjects, and combined...

This study aimed to investigate whether Chronic Kidney Disease (CKD) influences O2 supply including O2 delivery and release to the active muscles during maximal physical exercise. Twelve CKD patients undergoing dialysis therapy (HD group) and twelve healthy adults (CTR group) performed an incremental exercise test to determine maximal oxygen uptake (VO2peak ). Throughout the exercise, near-infrared spectroscopy allowed the investigation of changes in oxyhemoglobin (∆O2 Hb), deoxyhemoglobin (∆HHb), and total hemoglobin (∆THb) in the vastus lateralis muscle...

Biosensors applied in veterinary medicine serve as a noninvasive method to determine the health status of animals and, indirectly, their level of welfare. Near infrared spectroscopy (NIRS) has been suggested as a technology with this application. This study presents preliminary in vivo time domain NIRS measurements of optical properties (absorption coefficient, reduced scattering coefficient, and differential pathlength factor) and hemodynamic parameters (concentration of oxygenated hemoglobin, deoxygenated hemoglobin, total hemoglobin, and tissue oxygen saturation) of tissue domestic animals, specifically of skeletal muscle (4 dogs and 6 horses) and head (4 dogs and 19 sheep)...

PURPOSE: To determine the effects of load carriage in normoxia and normobaric hypoxia on ventilatory responses, hemodynamics, tissue oxygenation, and metabolism. METHODS: Healthy males (n = 12) completed 3 randomly ordered baseline graded exercise tests in the following conditions: (1) unloaded normoxic (U: FI O2  = 20.93%), (2) loaded (~ 30 kg) normoxic (LN), and (3) loaded hypoxic simulating ~ 3650 m (LH: FI O2  =  ~ 13%)...

Although in recent years near-infrared spectroscopy has been used in many sports to monitor muscle oxygen saturation (SmO2 ), there is a lack of knowledge about the sex differences in SmO2 during exercise in different muscles. Our study aimed to examine SmO2 differences in muscles between female and male cyclists, during a graded cycling test and at the first and second lactate thresholds. Twenty-five trained cyclists and triathletes [15 males: 23 ±7 years, 1.78 ±0.05 m, 70.2 ±5.3 kg, and 10 females: 22 ±5 years, 1...

INTRODUCTION: It is known that maximum oxygen uptake depends on age, sex, endurance capacity, and chronic heart failure. However, due to the required invasive or often applied non-continuous approaches, less is known on underlying central and peripheral factors. Thus, this study aimed to investigate the effects of age, sex, endurance capacity, and chronic heart failure on non-invasively and continuously measured central and peripheral factors of oxygen uptake. METHODS: 15 male children (11 ± 1 years), 15 male (24 ± 3 years) and 14 female recreationally active adults (23 ± 2 years), 12 male highly trained endurance athletes (24 ± 3 years), and 10 male elders (59 ± 6 years) and 10 chronic heart failure patients (62 ± 7 years) were tested during a cardiopulmonary exercise test on a cycling ergometer until exhaustion for: blood pressure, heart rate, stroke volume, cardiac output, cardiac power output, vastus lateralis muscle oxygen saturation, and (calculated) arterio-venous oxygen difference...

BACKGROUND: Following acute COVID-19, a substantial proportion of patients showed symptoms and sequelae for several months, namely the post-acute sequelae of COVID-19 (PASC) syndrome. Major phenomena are exercise intolerance, muscle weakness and fatigue. We aimed to investigate the physiopathology of exercise intolerance in patients with PASC syndrome by structural and functional analyses of skeletal muscle. METHODS: At least 3 months after infection, non-hospitalized patients with PASC (n=11,ys:54±11; PASC) and patients without long-term symptoms (n=12,ys:49±9; CTRL) visited the laboratory on four non-consecutive days...

When high-intensity exercise is performed until exhaustion a "functional reserve" (FR) or capacity to produce power at the same level or higher than reached at exhaustion exists at task failure, which could be related to reactive oxygen and nitrogen species (RONS)-sensing and counteracting mechanisms. Nonetheless, the magnitude of this FR remains unknown. Repeated bouts of supramaximal exercise at 120% of VO2 max interspaced with 20s recovery periods with full ischaemia were used to determine the maximal FR...

PURPOSE: The physiological examination of boxing has been limited to systemic response in amateur athletes. The demands of professional boxing have been overlooked, despite the different competition format. We sought to determine the physiological demands placed on skeletal muscle in professional boxing. METHODS: Ten male professional boxers (age 26 ± 5 years, height 177 ± 4 cm, weight 71 ± 6 kg) were recruited for this observational study...