Effects of light-intensity physical activity on cardiometabolic parameters in young adults with overweight and obesity: The SED-ACT randomized controlled crossover trial.

AIMS: To investigate how a change in body position with light-intensity physical activity (PA) 'snacks' (LIPAS, alternate sitting and standing, walking or standing continuously) compared with uninterrupted prolonged sitting affects glucose metabolism and heart rate variability (HRV) parameters in young adults with overweight and obesity. MATERIALS AND METHODS: We conducted a four-arm randomized controlled crossover trial. The following conditions were tested during an 8-h simulated workday: uninterrupted prolonged sitting (SIT), alternate sitting and standing (SIT-STAND; 2.5 h total), continuous standing (STAND), and continuous walking (1.0 mph; WALK). The primary outcome was to investigate how a change in body position (alternate sitting and standing, walking or standing continuously) compared with uninterrupted sitting affects mean 8-h glucose metabolism. Secondary outcomes included the effects on 2-h postprandial glucose concentrations, as well as on 8-h/24-h heart rate and HRV parameters, in the respective study arms. Capillary blood samples were drawn from an hyperemised earlobe in the fasted state and once every hour during each trial intervention by puncturing the earlobe with a lancet and collecting 20 µL of blood (Biosen S-Line Lab+; EKF diagnostics, Barleben, Germany). HRV was assessed for 24 h including the 8-h intervention phase, and a home phase by means of a Holter electrocardiogram. All participants received the same standardized non-relativised breakfast and lunch during the four trial visits. RESULTS: Seventeen individuals (eight women, mean age 23.4 ± 3.3 years, body mass index 29.7 ± 3.8 kg/m2, glycated haemoglobin level 34.8 ± 3.1 mmol/mol [5.4 ± 0.3%], body fat 31.8 ± 8.2%) completed all four trial arms. Compared with SIT (89.4 ± 6.8 mg/dL), 8-h mean glucose was lower in all other conditions (p < 0.05) and this was statistically significant compared with WALK (86.3 ± 5.2 mg/dL; p = 0.034). Two-hour postprandial glucose after breakfast was approximately 7% lower for WALK compared with SIT (p = 0.002). Furthermore, significant time × condition effects on HRV parameters favouring light-intensity walking were observed (p < 0.001). CONCLUSIONS: Replacement and interruption of prolonged sitting with light-intensity walking showed a significant blood glucose-lowering effect and improved HRV during an 8-h work environment in young adults with overweight and obesity.

Effect of Prenatal Yoga versus Moderate-Intensity Walking on Cardiorespiratory Adaptation to Acute Psychological Stress: Insights from Non-Invasive Beat-to-Beat Monitoring.

We recently reported enhanced parasympathetic activation at rest throughout pregnancy associated with regular yoga practice. The present study presents a secondary analysis of data collected within a prospective cohort study of 33 pregnant women practicing yoga once weekly throughout pregnancy and 36 controls not involved in formal pregnancy exercise programs. The objective was to assess the impact of prenatal yoga on the autonomic nervous system stress response. Healthy pregnant women with singleton pregnancies were recruited in the first trimester. There was no significant difference in the maternal body mass index (BMI) between the yoga group and the controls (24.06 ± 3.55 vs. 23.74 ± 3.43 kg/m2, p = 0.693). Women practicing yoga were older (28.6 ± 3.9 vs. 31.3 ± 3.5 years, p = 0.005) and more often nulliparous (26 (79%) vs. 18 (50%), p = 0.001). We studied heart rate variability (HRV) parameters in the time domain (SDNN, standard deviation of regular R-R intervals, and RMSSD, square root of mean squared differences of successive R-R intervals) and frequency domain (ln(LF/HF), natural logarithm of low-frequency to high-frequency power), as well as synchronization indices of heart rate, blood pressure and respiration during and immediately following acute psychological stress of a standardized mental challenge test. Measurements were performed once per trimester before and after yoga or a 30 min moderate-intensity walk. Statistical comparison was performed using three-way analyses of variance (p < 0.05 significant). Time domain HRV parameters during and following mental challenge in the yoga group were significantly higher compared to the controls regardless of the trimester (F = 7.22, p = 0.009 for SDNN and F = 9.57, p = 0.003 for RMSSD, respectively). We observed no significant differences in the yoga group vs. the controls in terms of ln(LF/HF) and synchronization indices. Regular prenatal yoga practice was associated with a significantly reduced sympathetic response to mental challenge and quicker recovery after acute psychological stress. These effects persisted throughout pregnancy with regular practice.

Evaluation of the Value of Histological Examination for the Prediction of Genetic Thoracic Proximal Aortopathies.

Background: Heritable connective tissue disorders are often accompanied by an increased risk for thoracic aortic aneurysm and dissection (TAAD). Profound knowledge of the underlying pathology may have an impact on individual treatment, systematic follow-up, and early detection by the screening of offspring. The aim of this study, based in a single high-volume tertiary center, was an analysis of the diagnostic validity of histopathologic findings in patients with TAAD due to these findings' accuracy in diagnosing heritable connective tissue disorders. Methods: Therefore, genetic testing by next-generation sequencing (NGS) was performed to evaluate the correlations. In total, 65 patients with TAAD undergoing surgical treatment before the age of 60 years or with age up to 80 years if they had offspring at the time of the procedure were included in the analysis. Results: In our cohort, no certain correlation of histological findings to the results of genetic diagnostics in patients with clinically relevant aortic pathology could be shown. Patients with histopathologic findings for heritable connective tissue disorder and a positive gene variant were 11.6 years younger than patients without mutation and without histological evidence for connective tissue disorder. Conclusions: Genetic clarification is useful to define the specific genotype of the disease of the aortic wall in the case of non-specific histological characteristics.