Hypoxic high-intensity interval training in individuals with overweight and obesity.

Combining moderate-intensity exercise training with hypoxic exposure may induce larger improvement in cardiometabolic risk factors and health status compared with normoxic exercise training in obesity. Considering the greater cardiometabolic effects of high-intensity intermittent training (HIIT), we hypothesized that hypoxic high-volume HIIT (H-HIIT) would induce greater improvement in cardiorespiratory fitness and health status despite a lower absolute training workload than normoxic HIIT (N-HIIT) in overweight/obesity. Thirty-one subjects were randomized to an 8-week H-HIIT [10 male and 6 female; age: 51.0 ± 8.3 years; body mass index (BMI): 31.5 ± 4 kg·m-2] or N-HIIT (13 male and 2 female; age: 52.0 ± 7.5 years; BMI: 32.4 ± 4.8 kg·m-2) program (3 sessions/week; cycling at 80% or 100% of maximal workload for H-HIIT and N-HIIT, respectively; target arterial oxygen saturation for H-HIIT 80%, [Formula: see text] ∼0.12, i.e., ∼4,200 meters above sea level). Before and after training, the following evaluations were performed: incremental maximal and submaximal cycling tests, pulse-wave velocity, endothelial function, fasting glucose, insulin, lipid profile, and body composition. Maximal exercise (V̇o2peak: H-HIIT +14.2% ± 8.3% vs. N-HIIT +12.1 ± 8.8%) and submaximal (ventilatory thresholds) capacity and exercise metabolic responses (power output at the crossover point and at maximal fat oxidation rate) increased significantly in both groups, with no significant difference between groups and without other cardiometabolic changes. H-HIIT induced a greater peak ventilatory response (ANOVA group × time interaction F = 7.4, P = 0.016) compared with N-HIIT. In overweight/obesity, the combination of normobaric hypoxia and HIIT was not superior for improving cardiorespiratory fitness improvement compared with HIIT in normoxia, although HIIT in hypoxia was performed at a lower absolute training workload.

High-intensity interval training to promote cerebral oxygenation and affective valence during exercise in individuals with obesity.

Left/right prefrontal cortex (PFC) activation is linked to positive/negative affects, respectively. Besides, larger left PFC oxygenation during exercise relates to higher cardiorespiratory fitness (CRF). High-intensity interval training (HIIT) is superior to moderate-intensity continuous training (MICT) in improving CRF. The influence of training on PFC oxygenation and affects during exercise in individuals with obesity is, however, currently unknown. Twenty participants with obesity (14 males, 48 ± 8 years, body-mass index = 35 ± 6 kg·m-2) were randomised to MICT [50% peak work rate (WRpeak)] or HIIT (1-min bouts 100% WRpeak; 3 sessions/week, 8 weeks). Before/after training, participants completed an incremental ergocycle test. Near-infrared spectroscopy and the Feeling Scale assessed PFC oxygenation and affects during exercise, respectively. Improvements in CRF (e.g., WRpeak: 32 ± 14 vs 20 ± 13 W) were greater after HIIT vs MICT (p < 0.05). Only HIIT induced larger left PFC oxygenation (haemoglobin difference from 7 ± 6 to 10 ± 7 µmol) and enhanced affective valence (from 0.7 ± 2.9 to 2.2 ± 2.0; p < 0.05) at intensities ≥ second ventilatory threshold. Exercise-training induced changes in left PFC oxygenation correlated with changes in CRF [e.g., WRpeak (% predicted), r = 0.46] and post-training affective valence (r = 0.45; p < 0.05). HIIT specifically improved left PFC oxygenation and affects during exercise in individuals with obesity. Implementing HIIT in exercise programmes may therefore have relevant implications for the management of obesity, since greater affective response to exercise is thought to be associated with future commitment to physical activity.

Effects of high intensity interval training on sustained reduction in cardiometabolic risk associated with overweight/obesity. A randomized trial.

Background: Considering the potential greater cardiocirculatory effects of high intensity interval training (HIIT), we hypothesized that a 2-month supervised high volume short interval HIIT would induce greater improvements in CRF and cardiometabolic risk and increase long-term maintenance to physical activity compared to isocaloric moderate intensity continuous training (MICT) in overweight/obesity. Methods: Sixty (19 females) subjects with overweight/obesity were randomized to three training programs (3 times/week for 2 months): MICT (45 min, 50% peak power output-PPO), HIIT (22 × 1-min cycling at 100% PPO/1-min passive recovery) and HIIT-RM (RM: recovery modulation, i.e. subjects adjusted passive recovery duration between 30s and 2 min). After the intervention, participants no longer benefited from supervised physical activity and were instructed to maintain the same exercise modalities on their own. We assessed anthropometrics, body composition, CRF, fat oxidation, lipid profile, glycemic balance, low-grade inflammation, vascular function, spontaneous physical activity and motivation for eating at three time points: baseline (T0), 4 days after the end of the 2-month supervised training program (T2) and 4 months after the end of the training program (T6). Results: HIIT/HIIT-RM induced greater improvement in VO2peak (between +14% and +17%), power output at ventilatory thresholds and at maximal fat oxidation rate (+25%) and waist circumference (-1.53 cm) compared to MICT and tended to decrease insulin resistance. During the four-month follow-up period during which exercise in autonomy was prescribed, HIIT induced a greater preservation of CRF, decreases in total and abdominal fat masses and total cholesterol/HDL. Conclusion: We have shown greater short-term benefits induced by a high volume short interval (1 min) HIIT on cardiorespiratory fitness and cardiometabolic risk over an isocaloric moderate intensity continuous exercise in persons with overweight/obesity. We also showed greater long-term effects (i.e. after 4 months) of this exercise modality on the maintenance of CRF, decreases in total and abdominal fat masses and total cholesterol/HDL.

A randomized sham-controlled trial on the effect of continuous positive airway pressure treatment on gait control in severe obstructive sleep apnea patients.

To determine the effect of continuous positive airway pressure (CPAP), the gold standard treatment for obstructive sleep apnea syndrome (OSAS), on gait control in severe OSAS patients. We conducted a randomized, double-blind, parallel-group, sham-controlled monocentric study in Grenoble Alpes University Hospital, France. Gait parameters were recorded under single and dual-task conditions using a visuo-verbal cognitive task (Stroop test), before and after the 8-week intervention period. Stride-time variability, a marker of gait control, was the primary study endpoint. Changes in the determinants of gait control were the main secondary outcomes. ClinicalTrials.gov Identifier: (NCT02345694). 24 patients [median (Q1; Q3)]: age: 59.5 (46.3; 66.8) years, 87.5% male, body mass index: 28.2 (24.7; 29.8) kg. m-2, apnea-hypopnea index: 51.6 (35.0; 61.4) events/h were randomized to be treated by effective CPAP (n = 12) or by sham-CPAP (n = 12). A complete case analysis was performed, using a mixed linear regression model. CPAP elicited no significant improvement in stride-time variability compared to sham-CPAP. No difference was found regarding the determinants of gait control. This study is the first RCT to investigate the effects of CPAP on gait control. Eight weeks of CPAP treatment did not improve gait control in severe non-obese OSAS patients. These results substantiate the complex OSAS-neurocognitive function relationship.

What are the barriers to the completion of a home-based rehabilitation programme for patients awaiting surgery for lung cancer: a prospective observational study.

OBJECTIVES: Home-based rehabilitation programmes (H-RPs) could facilitate the implementation of pulmonary rehabilitation prior to resection for non-small cell lung cancer (NSCLC), but their feasibility has not been evaluated. The aim of this study was to identify determinants of non-completion of an H-RP and the factors associated with medical events occurring 30 days after hospital discharge. DESIGN: A prospective observational study. INTERVENTION: All patients with confirmed or suspected NSCLC were enrolled in a four-component H-RP prior to surgery: (i) smoking cessation, (ii) nutritional support, (iii) physiotherapy (at least one session/week) and (iv) home cycle-ergometry (at least three times/week). OUTCOMES: The H-RP was defined as 'completed' if the four components were performed before surgery. RESULTS: Out of 50 patients included, 42 underwent surgery (80% men; median age: 69 (IQR 25%-75%; 60-74) years; 64% Chronic Obstructive Pulmonary Disease (COPD); 29% type 2 diabetes). Twenty patients (48%) completed 100% of the programme. The median (IQR) duration of the H-RP was 32 (19; 46) days. Multivariate analysis showed polypharmacy (n=24) OR=12.2 (95% CI 2.0 to 74.2), living alone (n=8) (single vs couple) OR=21.5 (95% CI 1.4 to >100) and a long delay before starting the H-RP (n=18) OR=6.24 (95% CI 1.1 to 36.6) were independently associated with a risk of non-completion. In univariate analyses, factors associated with medical events at 30 days were H-RP non-completion, diabetes, polypharmacy, social precariousness and female sex. CONCLUSION: Facing multiple comorbidities, living alone and a long delay before starting the rehabilitation increase the risk of not completing preoperative H-RP. TRIAL REGISTRATION NUMBER: NCT03530059.

Selective loss of a LAP1 isoform causes a muscle-specific nuclear envelopathy.

The nuclear envelope (NE) separates the nucleus from the cytoplasm in all eukaryotic cells. A disruption of the NE structure compromises normal gene regulation and leads to severe human disorders collectively classified as nuclear envelopathies and affecting skeletal muscle, heart, brain, skin, and bones. The ubiquitous NE component LAP1B is encoded by TOR1AIP1, and the use of an alternative start codon gives rise to the shorter LAP1C isoform. TOR1AIP1 mutations have been identified in patients with diverging clinical presentations such as muscular dystrophy, progressive dystonia with cerebellar atrophy, and a severe multi-systemic disorder, but the correlation between the mutational effect and the clinical spectrum remains to be determined. Here, we describe a novel TOR1AIP1 patient manifesting childhood-onset muscle weakness and contractures, and we provide clinical, histological, ultrastructural, and genetic data. We demonstrate that the identified TOR1AIP1 frameshift mutation leads to the selective loss of the LAP1B isoform, while the expression of LAP1C was preserved. Through comparative review of all previously reported TOR1AIP1 cases, we delineate a genotype/phenotype correlation and conclude that LAP1B-specific mutations cause a progressive skeletal muscle phenotype, while mutations involving a loss of both LAP1B and LAP1C isoforms induce a syndromic disorder affecting skeletal muscle, brain, eyes, ear, skin, and bones.

Cardiovascular and metabolic responses to passive hypoxic conditioning in overweight and mildly obese individuals.

Although severe intermittent hypoxia (IH) is well known to induce deleterious cardiometabolic consequences, moderate IH may induce positive effects in obese individuals. The present study aimed to evaluate the effect of two hypoxic conditioning programs on cardiovascular and metabolic health status of overweight or obese individuals. In this randomized single-blind controlled study, 35 subjects (54 ± 9.3 yr, 31.7 ± 3.5 kg/m2) were randomized into three 8-wk interventions (three 1-h sessions per week): sustained hypoxia (SH), arterial oxygen saturation ([Formula: see text]) = 75%; IH, 5 min [Formula: see text] = 75% - 3 min normoxia; normoxia. Ventilation, heart rate, blood pressure, and tissue oxygenation were measured during the first and last hypoxic conditioning sessions. Vascular function, blood glucose and insulin, lipid profile, nitric oxide metabolites, and oxidative stress were evaluated before and after the interventions. Both SH and IH increased ventilation in hypoxia (+1.8 ± 2.1 and +2.3 ± 3.6 L/min, respectively; P < 0.05) and reduced normoxic diastolic blood pressure (-12 ± 15 and -13 ± 10 mmHg, respectively; P < 0.05), whereas changes in normoxic systolic blood pressure were not significant (+3 ± 9 and -6 ± 13 mmHg, respectively; P > 0.05). IH only reduced heart rate variability (e.g., root-mean-square difference of successive normal R-R intervals in normoxia -21 ± 35%; P < 0.05). Both SH and IH induced no significant change in body mass index, vascular function, blood glucose, insulin and lipid profile, nitric oxide metabolites, or oxidative stress, except for an increase in superoxide dismutase activity following SH. This study indicates that passive hypoxic conditioning in obese individuals induces some positive cardiovascular and respiratory improvements despite no change in anthropometric data and even a reduction in heart rate variability during IH exposure.

Hypoxic Exercise Training to Improve Exercise Capacity in Obese Individuals.

INTRODUCTION: Combining exercise training with hypoxic exposure has been recently proposed as a new therapeutic strategy to improve health status of obese individuals. Whether hypoxic exercise training (HET) provides greater benefits regarding body composition and cardiometabolic parameters than normoxic exercise training (NET) remains, however, unclear. We hypothesized that HET would induce greater improvement in exercise capacity and health status than NET in overweight and obese individuals. METHODS: Twenty-three subjects were randomized into 8-wk HET (11 men and 1 woman; age, 52 ± 12 yr; body mass index, 31.2 ± 2.4 kg·m) or NET (eight men and three women; age, 56 ± 11 yr; body mass index, 31.8 ± 3.2 kg·m) programs (three sessions per week; constant-load cycling at 75% of maximal heart rate; target arterial oxygen saturation for HET 80%, FiO2 ~0.13, i.e., ~3700 m a.s.l.). Before and after the training programs, the following evaluations were performed: incremental maximal and submaximal cycling tests, measurements of pulse-wave velocity, endothelial function, fasting glucose, insulin and lipid profile, blood NO metabolites and oxidative stress, and determination of body composition by magnetic resonance imaging. RESULTS: Peak oxygen consumption and maximal power output increased significantly after HET only (peak oxygen consumption HET + 10% ± 11% vs NET + 1% ± 10% and maximal power output HET + 11% ± 7% vs NET + 3% ± 10%, P < 0.05). Submaximal exercise responses improved similarly after HET and NET. Except diastolic blood pressure which decreased significantly after both HET and NET, no change in vascular function, metabolic status and body composition was observed after training. Hypoxic exercise training only increased nitrite and reduced superoxide dismutase concentrations. CONCLUSIONS: Combining exercise training and hypoxic exposure may provide some additional benefits to standard NET for obese individual health status.

Effectiveness of a lightweight portable auto-CPAP device for the treatment of sleep apnea during high altitude stages of the Dakar Rally: a case report.

Sleep-related breathing disturbances are exacerbated at altitude in patients with Obstructive Sleep Apnea (OSA). The objective of this case report was to determine if a portable auto-CPAP device effectively treated sleep apnea across different altitudes. We report the severity of sleep apnea from 60 to 12,000 feet high in a man with severe OSA (Apnea Hypopnea Index at diagnosis = 60 events/hour) during the 2017 Dakar rally over the Andes mountains. The man was equipped with a lightweight portable auto-CPAP device with a narrow window [6-8 cmH2O]. Pressures delivered and corresponding residual events were assessed at different altitudes. The 95th percentile pressure reached the maximal set pressure at the highest altitudes, and residual AHI increased from 5 events/hour to 45 events/hour at the highest altitudes. Potential mechanisms behind the development of central apnea, and optimal clinical management at altitude are discussed in the light of the findings.

Impaired cerebral oxygenation and exercise tolerance in patients with severe obstructive sleep apnea syndrome.

OBJECTIVE AND BACKGROUND: Impaired cerebral blood flow and cerebrovascular reactivity to hypercapnia during wakefulness at rest as well as reduced exercise tolerance have been reported in severe obstructive sleep apnea (OSA) patients. Impaired cerebral oxygenation and hemodynamics can contribute to reduced exercise performance. We hypothesized that (i) OSA patients show impaired cerebrovascular response both during exercise and in response to hypercapnia together with reduced exercise tolerance and (ii) continuous positive airway pressure (CPAP) treatment improves these alterations in cerebral oxygenation. METHODS: Fifteen OSA patients and 12 healthy matched controls performed a hypercapnic response test and a maximal cardiopulmonary exercise test before and after eight weeks of CPAP treatment or control period. Prefrontal cortex and muscle oxygenation were assessed by near-infrared spectroscopy (NIRS) during both tests. RESULTS: Cerebrovascular reactivity to hypercapnia was impaired in OSA patients (lower increase in oxyhemoglobin [0.29 ± 0.19 vs 0.44 ± 0.14 µmol mmHg-1] and total hemoglobin [0.14 ± 0.15 vs 0.26 ± 0.09 µmol mmHg-1]) compared to controls. Reduced prefrontal cortex oxygen extraction and total blood volume (ie, lower increase in deoxyhemoglobin [1.76 ± 1.57 vs 3.43 ± 2.08 µmol] and total hemoglobin [5.36 ± 7.08 vs 8.55 ± 5.13 µmol at exhaustion], respectively) during exercise together with a reduced exercise tolerance (ie, lower peak oxygen consumption) were observed in OSA patients compared to controls. CPAP treatment did not induce any improvement in cerebrovascular response during hypercapnic response test and exercise. CONLUSIONS: This study demonstrates that cerebrovascular response to exercise is altered in OSA and may contribute to exercise intolerance in these patients. Prefrontal cortex oxygenation and exercise tolerance are not significantly improved following eight weeks of CPAP treatment. CLINICAL TRIAL REGISTRATION: NCT02854280.

Disability in adults with arthrogryposis is severe, partly invisible, and varies by genotype.

OBJECTIVE: To understand the disability of adults with arthrogryposis multiplex congenita (AMC), a rare disease spectrum characterized by at least 2 joint contractures at birth in different body areas. METHODS: This is a retrospective analysis of data for unselected persons with AMC referred to the French center for adults with AMC from 2010 to 2016. All underwent a pluriprofessional systematic and comprehensive investigation of deficits, activity limitation, and participation restriction according to the International Classification of Functioning, Disability and Health and genetic analysis when indicated. Participants were divided by amyoplasia and other AMC types. RESULTS: Mean (SD) age of the 43 participants (27 female) was 33.2 (13.4) years; 28 had amyoplasia and 15 other types of AMC. Beyond joint stiffness, deformities, and muscle weakness, the well-known core symptoms that we quantified and for which first-line treatment involved technical aids, other less visible disorders that could contribute to severe participation restriction were particularly pain and psychological problems including anxiety, fatigue, difficulty in sexual life, altered self-esteem, and feelings of solitude. Severe respiratory disorders were infrequent and were linked to PIEZO2 mutations. Gait disorders were not due to respiratory impairment but to skeletal problems and were always associated with amyoplasia when severe. Functional independence was worse but respiratory and swallowing capacities were better with amyoplasia than other AMC types. CONCLUSION: This study describes disability patterns of a cohort of adults with AMC by genotype. The disability of adults with AMC is influenced by genotype, with important invisible disability.

Neuromuscular Dysfunction and Cortical Impairment in Sleep Apnea Syndrome.

PURPOSE: Lower muscle strength and endurance have been reported in severe obstructive sleep apnea (OSA). Increased intracortical inhibition previously reported at rest in OSA suggests central neuromuscular impairments in these patients. We hypothesized that (i) OSA patients demonstrate reduced knee extensor strength and endurance due to central impairments and (ii) continuous positive airway pressure (CPAP) treatment improves neuromuscular function in these patients. METHODS: Twelve OSA patients and 11 healthy controls performed intermittent knee extensions until task failure before and after 8 wk of CPAP treatment or control period. Maximal voluntary contraction, voluntary activation and corticospinal excitability and inhibition assessed by single- and paired-pulse transcranial magnetic stimulation were measured before and during the fatiguing task. RESULTS: Time to exhaustion was lower in OSA (before CPAP treatment: 1008 ± 549 s; after CPAP treatment: 975 ± 378 s) compared with controls (before control period: 1476 ± 633 s; after control period: 1274 ± 506 s; P = 0.017). Obstructive sleep apnea patients had reduced maximal voluntary contraction and VATMS compared with controls throughout the fatiguing task as well as increased intracortical inhibition (all P < 0.05). Continuous positive airway pressure treatment did not induce any changes in neuromuscular function (P > 0.05 for all parameters). CONCLUSIONS: This study demonstrates that severe OSA patients have cortical impairments which are likely contributing to their reduced knee extensors strength and endurance. Both cortical impairments and neuromuscular function are not improved after 8 wk of CPAP treatment.

Continuous positive airway pressure improves gait control in severe obstructive sleep apnoea: A prospective study.

STUDY AIM: Severe obstructive sleep apnoea (OSA) can lead to neurocognitive alterations, including gait impairments. The beneficial effects of continuous positive airway pressure (CPAP) on improving excessive daytime sleepiness and daily functioning have been documented. However, a demonstration of CPAP treatment efficacy on gait control is still lacking. This study aims to test the hypothesis that CPAP improves gait control in severe OSA patients. MATERIAL AND METHODS: In this prospective controlled study, twelve severe OSA patients (age = 57.2±8.9 years, body mass index = 27.4±3.1 kg·m-2, apnoea-hypopnoea index = 46.3±11.7 events·h-1) and 10 healthy matched subjects were included. Overground gait parameters were recorded at spontaneous speed and stride time variability, a clinical marker of gait control, was calculated. To assess the role of executive functions in gait and postural control, a dual-task paradigm was applied using a Stroop test as secondary cognitive task. All assessments were performed before and after 8 weeks of CPAP treatment. RESULTS: Before CPAP treatment, OSA patients had significantly larger stride time variability (3.1±1.1% vs 2.1±0.5%) and lower cognitive performances under dual task compared to controls. After CPAP treatment, stride time variability was significantly improved and no longer different compared to controls. Cognitive performance under dual task also improved after CPAP treatment. CONCLUSION: Eight weeks of CPAP treatment improves gait control of severe OSA patients, suggesting morphological and functional cerebral improvements. Our data provide a rationale for further mechanistic studies and the use of gait as a biomarker of OSA brain consequences.

Ventilatory support or respiratory muscle training as adjuncts to exercise in obese CPAP-treated patients with obstructive sleep apnoea: a randomised controlled trial.

BACKGROUND: Obstructive sleep apnoea (OSA) and obesity are interdependent chronic diseases sharing reduced exercise tolerance and high cardiovascular risk. INTERVENTION: A 3-month intervention with innovative training modalities would further improve functional capacity and cardiovascular health than usual cycle exercise training in already continuous positive airway pressure (CPAP)-treated obese patients with OSA. METHODS: Fifty three patients (35

Quadriceps muscle fat infiltration is associated with cardiometabolic risk in COPD.

PURPOSE: Losses of peripheral muscle mass and ectopic fat accumulation have been associated with cardiometabolic morbidity in COPD. We aimed at identifying the relationship between quadriceps muscle fat infiltration and cardiovascular risk. MATERIALS AND METHODS: From 2009 to 2014, 78 COPD patients (64 ± 8 years; 80% male) were prospectively included after having given written consent (ethical committee approval number: 2006-A00491-50). The cohort was divided into three groups (tertiles) according to body mass index (BMI), low [15 < BMI≤23·3], middle [23·3 < BMI≤27·6] and high [27·6 < BMI≤36] kg/m²). Measurements were respiratory function, plasmatic biomarkers and surrogate markers of cardiovascular risk (arterial stiffness and endothelial function). Mid-thigh quadriceps muscle volume and per cent of muscle fat infiltration, as assessed by 64-slice CT scanning, were compared between the tertiles. ANOVA or Kruskal-Wallis tests were used for statistical analyses with Bonferroni's correction for the 'post hoc' tests. RESULTS: Intramuscular fat volume was 52% [95% CI, 43 to 60%] of total quadriceps volume in high BMI vs. 47% [38 to 55%] and 34% [29 to 38%] in the middle and low-BMI groups, respectively (P<0·0001), without differences between groups in fat-free muscle volumes. Elevated muscle fat infiltration correlated with lower thiol to protein ratios in the whole population reflecting impaired antioxidant capacity (r = 0·50; P = 0·009). Furthermore, muscle fat infiltration was linked to endothelial dysfunction (r = -0·49, P = 0·01) in the low-BMI group. CONCLUSION: Skeletal muscle fat infiltration may be an indicator of increased cardiometabolic risk in both obese and lean COPD patients.

Acute Feasibility of Neuromuscular Electrical Stimulation in Severely Obese Patients with Obstructive Sleep Apnea Syndrome: A Pilot Study.

Objective. Obesity and obstructive sleep apnea (OSA) are closely interconnected conditions both leading to high cardiovascular risk. Inactivity is frequent and physical activity programs remain difficult in these patients. We investigated the acute feasibility of two neuromuscular electrical stimulation (NMES) modalities in extremely inactive obese patients with OSA. Design. A randomized cross-over study, with two experimental sessions (one per condition: multipath NMES versus conventional NMES). Setting. Outpatient research hospital. Subjects. Twelve patients with obesity, already treated for OSA. Interventions. No intervention. Measures. Feasibility outcomes included NMES current intensity, knee extension force evoked by NMES, and self-reported discomfort. Results. We found higher current intensity, a trend to significantly higher evoked force and lower discomfort during multipath NMES versus conventional NMES, suggesting better tolerance to the former NMES modality. However, patients were rapidly limited in the potential of increasing current intensity of multipath NMES. Conclusion. Both NMES modalities were feasible and relatively well tolerated by obese patients with OSA, even if multipath NMES showed a better muscle response/discomfort ratio than conventional NMES. There is an urgent need for a proof-of-concept study and interventional randomized controlled trials comparing NMES therapy versus current care to justify its utilization in obese and apneic patients with low physical activity levels.

Physiological correlates to spontaneous physical activity variability in obese patients with already treated sleep apnea syndrome.

BACKGROUND/OBJECTIVES: Physical activity is promoted in patients with sleep disorders and obesity. The aim of the present study was to assess physiological factors influencing objectively measured spontaneous physical activity in already treated patients for obstructive sleep apnea (OSA) by nocturnal continuous positive airway pressure (CPAP). SUBJECTS/METHODS: Fifty-five patients (age = 53 ± 3 years; body mass index (BMI) = 38 ± 3 kg/m2; compliance with CPAP >4 h/night) were prospectively included. Measurements were 5-day actigraphy with metabolic equivalent of task (METs) assessment, body composition, pulmonary function, quadriceps and respiratory muscle strength, exercise capacity (6-min walking distance and maximal aerobic capacity), as well as sleep parameters (sleepiness, duration, oxygen saturation, and micro-arousals during sleep) and quality of life (SF-36 questionnaire). RESULTS: As expected, the number of steps per day (6879 ± 2511) and mean intensity of physical activity (1.38 ± 0.15 METs) were below the recommendations for obese population. In age-adjusted stepwise regression models, peak oxygen consumption (VO2 peak) and peak dyspnea perception during incremental exercise test were independent predictors of the number of steps per day (r = 0.49, p = 0.001) although VO2 peak and peak minute ventilation were independent predictors of intensity of physical activity (in METs/day; r = 0.49, p = 0.001). CONCLUSIONS: In severe obese patients with OSA, exercise capacity, ventilatory requirement, and dyspnea perception were main physiological components of physical activity. These results emphasize the need to consider specific training interventions that increase ability to perform intense physical activity in obese OSA.

Neuromuscular Fatigue during Prolonged Exercise in Hypoxia.

PURPOSE: Prolonged cycling exercise performance in normoxia is limited because of both peripheral and central neuromuscular impairments. It has been reported that cerebral perturbations are greater during short-duration exercise in hypoxia compared with normoxia. The purpose of this study was to test the hypothesis that central deficits are accentuated in hypoxia compared with normoxia during prolonged (three bouts of 80 min separated by 25 min) whole-body exercise at the same relative intensity. METHODS: Ten subjects performed two sessions consisting of three 80-min cycling bouts at 45% of their relative maximal aerobic power in normoxia and hypoxia (FiO2 = 0.12). Before exercise and after each bout, maximal voluntary force, voluntary activation assessed with nerve stimulation and transcranial magnetic stimulation, corticospinal excitability (motor evoked potential), intracortical inhibition (cortical silent period), and electrical (M-wave) and contractile (twitch and doublet peak forces) properties of the knee extensors were measured. Prefrontal and motor cortical oxygenation was also recorded during each cycling bout in both conditions. RESULTS: A significant but similar force reduction (≈-22%) was observed at the end of exercise in normoxia and hypoxia. The modifications of voluntary activation assessed with transcranial magnetic stimulation and nerve stimulation, motor evoked potential, cortical silent period, and M-wave were also similar in both conditions. However, cerebral oxygenation was reduced in hypoxia compared with normoxia. CONCLUSION: These findings show that when performed at the same relative low intensity, prolonged exercise does not induce greater supraspinal fatigue in hypoxia compared with normoxia. Despite lower absolute exercise intensities in hypoxia, reduced brain O2 availability might contribute to similar amounts of central fatigue compared with normoxia.

Safety and efficacy of a 6-month home-based exercise program in patients with facioscapulohumeral muscular dystrophy: A randomized controlled trial.

BACKGROUND: Previous randomized controlled trials investigating exercise training programs in facioscapulohumeral muscular dystrophy (FSHD) patients are scarce and of short duration only. This study assessed the safety and efficacy of a 6-month home-based exercise training program on fitness, muscle, and motor function in FSHD patients. METHODS: Sixteen FSHD patients were randomly assigned to training (TG) and control (CG) groups (both n = 8) in a home-based exercise intervention. Training consisted of cycling 3 times weekly for 35 minutes (combination of strength, high-intensity interval, and low-intensity aerobic) at home for 24 weeks. Patients in CG also performed an identical training program (CTG) after 24 weeks. The primary outcome was change in peak oxygen uptake (VO2 peak) measured every 6 weeks. The principal secondary outcomes were maximal quadriceps strength (MVC) and local quadriceps endurance every 12 weeks. Other outcome measures included maximal aerobic power (MAP) and experienced fatigue every 6 weeks, 6-minute walking distance every 12 weeks, and muscle characteristics from vastus lateralis biopsies taken pre- and postintervention. RESULTS: The compliance rate was 91% in TG. Significant improvements with training were observed in the VO2 peak (+19%, P = 0.002) and MAP by week 6 and further to week 24. Muscle endurance, MVC, and 6-minute walking distance increased and experienced fatigue decreased. Muscle fiber cross-sectional area and citrate synthase activity increased by 34% (P = 0.008) and 46% (P = 0.003), respectively. Dystrophic pathophysiologic patterns were not exacerbated. Similar improvements were experienced by TG and CTG. CONCLUSIONS: A combined strength and interval cycling exercise-training program compatible with patients' daily professional and social activities leads to significant functional benefits without compromising muscle tissue.