Clinical Physiology and Functional Imaging最新文献

In sports, physical recovery following exercise-induced fatigue is mediated via the reactivation of the parasympathetic nervous system (PNS). A noninvasive way to quantify the reactivation of the PNS is to assess vagally-mediated heart rate variability (vmHRV), which can then be used as an index of physical recovery. This systematic review and meta-analysis investigated the effects of physical recovery techniques following exercise-induced fatigue on vmHRV, specifically via the root mean square of successive differences (RMSSD). Randomized controlled trials from the databases PubMed, WebOfScience, and SportDiscus were included. Twenty-four studies were part of the systematic review and 17 were included in the meta-analysis. Using physical post-exercise recovery techniques displayed a small to moderate positive effect on RMSSD (k = 22, Hedges' g = 0.40, 95% confidence interval [CI] = 0.20–0.61, p = 0.04) with moderate heterogeneity. In the subgroup analyses, cold water immersion displayed a moderate to large positive effect (g = 0.75, 95% CI: 0.42–1.07) compared with none for other techniques. For exercise type, physical recovery techniques performed after resistance exercise (g = 0.69, 95% CI: 0.48–0.89) demonstrated a larger positive effect than after cardiovascular intermittent (g = 0.52, 95% CI: 0.06–0.97), while physical recovery techniques performed after cardiovascular continuous exercise had no effect. No significant subgroup differences for training status and exercise intensity were observed. Overall, physical post-exercise recovery techniques can accelerate PNS reactivation as indexed by vmHRV, but the effectiveness varies with the technique and exercise type.

To investigate effects of low workload respiratory muscle training (RMT) on respiratory muscle power and lung function in asthmatics, we recruited asthmatic persons who performed a 4-week training programme. The training included 20 daily ex- and inhalations with counter pressure 30% from the individual maximal expiratory pressure (MEP). Lung function was measured before and after the training programme and a follow-up period. The study also included several subjective endpoints for respiratory symptoms. A significant increase in a training group (n = 27) compared with a control group (n = 20) was seen in MEP (+12.4%, vs. +3.5%, p = 0.086), maximal inspiratory pressure (MIP) (+21.1% vs. +0.82%, p = 0.023), slow vital capacity (VC) (+3.7% vs. +1.5%, p = 0.023) and in forced expiratory time (FET, +15.5%, vs. −5.0%, p = 0.022). After being a control for group A, also group B performed similar RMT as group A. In the combined group (A and B, n = 47) MEP (11.3%, p = 0.003), MIP (19.73%, p < 0.001), VC (4.1%, p < 0.001) and FET (14.7%, p < 0.001) increased significantly from the baseline. Changes in other lung function variables were not indicative. On a scale of 1–5, the subjects perceived improvement in reduction of mucus secretion in the airways (median 3, p < 0.001), alleviation of coughing (median 3, p < 0.001) and reduction in dyspnoea (median 3, p < 0.001). As a conclusion, low workload respiratory training of 4 weeks improved respiratory muscle power and increased VC in patients with stable asthma.

Diagnosis and treatment of patients with suspected chronic coronary syndrome (CCS) currently relies on the degree of coronary artery stenosis and its significance for myocardial perfusion. However, myocardial perfusion can be affected by factors other than coronary stenosis. The aim of this study was to investigate to what extent sex, age, diabetes, hypertension and smoking affect quantitative myocardial perfusion, beyond the degree of coronary artery stenosis, in patients with suspected or established CCS. Eighty-six patients [median age 69 (range 46−86) years, 24 females] planned for elective coronary angiography due to suspected or established CCS were included. All patients underwent cardiac ¹³N-NH₃ positron emission tomography to quantify myocardial perfusion at rest and stress. Lowest myocardial perfusion (perfusion_min) at stress and rest and lowest myocardial perfusion reserve (MPR_min) for all vessel territories was used as dependent variables in a linear mixed model. Independent variables were vessel territory, degree of coronary artery stenosis (as a continuous variable of 0%−100% stenosis), sex, age, diabetes, hypertension and smoking habits. Degree of coronary artery stenosis (p < 0.001), male sex (1.8 ± 0.6 vs. 2.3 ± 0.6 mL/min/g, p < 0.001), increasing age (p = 0.025), diabetes (1.6 ± 0.5 vs. 2.0 ± 0.6 mL/min/g, p = 0.023) and smoking (1.9 ± 0.6 vs. 2.1 ± 0.6 mL/min/g, p = 0.052) were independently associated with myocardial perfusion_min at stress. Degree of coronary artery stenosis (p < 0.001), age (p = 0.040), diabetes (1.8 ± 0.6 vs. 2.3 ± 0.7, p = 0.046) and hypertension (2.2 ± 0.7 vs. 2.5 ± 0.6, p = 0.033) were independently associated with MPR_min. Sex, increasing age, diabetes, hypertension and smoking affect myocardial perfusion independent of coronary artery stenosis in patients with suspected or established CCS. Thus, these factors need to be considered when assessing the significance of reduced quantitative myocardial perfusion of patients with suspected or established CCS.

In type 1 diabetes, it is important to prevent diabetes-related complications and postural instability may be one clinically observable manifestation early on. This study was set to investigate differences between type 1 diabetics and healthy controls in variables of instrumented posturography assessment to inform about the potential of the assessment in early detection of diabetes-related complications. Eighteen type 1 diabetics with no apparent complications (HbA1c = 58 ± 9 mmol/L, diabetes duration = 15 ± 7 years) and 35 healthy controls underwent six 1-min two feet standing postural stability tests on a force plate. Study groups were comparable in age and anthropometric and performed the test with eyes open, eyes closed (EC), and EC head up with and without unstable padding. Type 1 diabetics exhibited greater sway (path length, p = 0.044 and standard deviation of velocity, p = 0.039) during the EC test with the unstable pad. Also, power spectral density indicated greater relative power (p = 0.043) in the high-frequency band in the test with EC head up on the unstable pad and somatosensory activity increased more (p = 0.038) when the unstable pad was added to the EC test. Type 1 diabetes may induce subtle changes in postural control requiring more active balancing when stability is challenged. Postural assessment using a portable easy-to-use force plate shows promise in detecting a diabetes-related decline in postural control that may be used as a sensitive biomarker of early-phase diabetes-related complications.

The present study aimed to evaluate forced expiration based on transverse abdominis (TrA) stiffness by identifying the relationship between TrA stiffness and peak expiratory flow (PEF) in both younger and older adults. We also assessed the relationship between diaphragm thickness and PEF. A total of 31 younger (21.24 ± 2.73 years) and 34 older (71.35 ± 5.26 years) adults were included in the present study. TrA muscle stiffness was measured at rest and during abdominal bracing using shear wave elastography. Diaphragm thickness was measured during deep inspiration and expiration using B-mode ultrasound, and respiratory function was assessed by measuring PEF using a spirometer. We found that TrA stiffness during bracing was significantly lower in older than younger adults (p < 0.05). Similarly, the difference in absolute stiffness of the TrA when bracing versus at rest was significantly lower in older than younger adults (p < 0.05). Additionally, TrA stiffness during bracing was positively associated with PEF in the younger group (r = 0.483), while a very weak correlation was found in the older group (r = 0.172). Similarly, PEF was moderately correlated with diaphragm thickness during expiration as well as during changes between inspiration and expiration in the younger group (r = 0.405 and r = 0.403); however, no significant correlation was found in the older group. These findings of the present study indicate that the variations in PEF between younger and older adults may be due to age-associated changes in the musculoskeletal structure and muscle fibre type.