Measuring effects of height on the autonomic nervous system in middle-aged adolescents using the very low frequency band of heart rate variability.

Previous studies have revealed the association between falling accidents and stress, measured via heart rate variability (HRV). However, none have studied this association using the very low frequency (VLF) band of HRV in adolescent populations. This study aimed to fill this gap by recruiting 90 adolescents to perform a light physical task at varying heights. Heart rates were used to calculate short-term HRV. The results showed a positive correlation between VLF bands and parasympathetic indices and a negative correlation with sympathetic indices, demonstrating the balancing effects of the autonomic modulation associated with height. The lowest VLF bands were obtained as 79.25 ms2 at 10 m (p < 0.001) and 62.87 ms2 at 9 m (p < 0.001) for the experienced and non-experienced male groups, respectively, and 28.09 ms2 at 6 m (p = 0.001) for the female group. The results also suggested the need for a relatively lower height restriction for female adolescents than for males.Practitioner summary: Increased working heights can cause stress, which leads to falling accidents. The very low frequency band was shown to be associated with parasympathetic and sympathetic indices. Furthermore, the results suggested that the height limit necessary for providing a safe working environment may be lower for female adolescents than for males.Abbreviations: HRV: heart rate variability; VLF: very low frequency; ms2: absolute power; ANS: autonomic nervous system; PNS: parasympathetic nervous system; SNS: sympathetic nervous system; RR: intervals between two successive peaks of R waves; RMSSD: root mean square of successive RR interval differences; SD1: Poincaré plot index of standard deviation 1; SD2: Poincaré plot index of standard deviation 2; HF: high frequency; LF: low frequency; BMI: body mass index; ECG: electrocardiography; HR: heart rate; FFT: fast Fourier transformation; IQR: interquartile range; r: non-parametric partial correlation coefficient; η2: eta-squared; EM: experienced males; NM: non-experienced males; NF: non-experienced females; EEG: electroencephalogram.

Walking activity increases physical abilities and subjective health in people with seven different types of disabilities.

Introduction: People with disabilities have a great risk of physical inactivity, which causes several diseases, dependency, and long-term care. Walking helps to increase physical activity, which leads to better overall health and independence. However, less research attention has focused on walking for people with disabilities, and even fewer studies have been considered for different types of disabilities. The present study aimed to demonstrate how walking distance was associated with people with seven different types of disabilities- including visual, hearing, physical/mobility, intellectual, learning, autism, and emotional/behavioral disabilities-in terms of their physical abilities and subjective health. Methods: A total of 378 participants (aged 13-65) were gathered from seven national organizations in Thailand. A survey questionnaire on aspects of physical abilities (i.e., walking distance or manually rolling wheelchair distance; body balance; weightlifting; exercise duration and frequency); and subjective health (i.e., health status and satisfaction) was completed online by all participants. Results: The walking distance was partially positive and associated with exercise duration, weightlifting, exercise frequency, and health status (all p values < 0.001), as well as body balance and health satisfaction (p = 0.001 and 0.004, respectively), after controlling for age, sex, and types of disability. This demonstrated that increasing the amount of distance walked could well lead to a more positive body and mind. Discussion: The present study suggests that the possibility of having a walk and/or encouraging people with disabilities to walk for greater distances can have a significant impact on both their physical and subjective health outcomes.

Postural Changes on Heart Rate Variability among Older Population: A Preliminary Study.

OBJECTIVE: This study aims to investigate an association between body postures and autonomic nervous system (ANS) responses through analysis of short-term heart rate variability (HRV) data obtained through electrocardiography. METHODS: Forty older individuals were recruited to form the sample. HRV measurements were taken in three positions-sitting, supine, and standing-and compared. RESULTS: Results demonstrated statistically significant differences in the HRV parameters used to examine the parasympathetic nervous system (PNS) and the sympathetic nervous system (SNS), specifically in the measurements obtained from the sitting position and the supine position (P < 0.001 for PNS and P = 0.011 for SNS). The differences in these parameters were, however, negligible between the sitting and the standing positions. Moreover, the ANS responses obtained in the sitting position were strongly and positively correlated with those in the standing position (r = 0.854 for PNS and r = 0.794 for SNS). These results suggested that the PNS and SNS parameters obtained while sitting were likely to be affected by orthostatic hypotension in much the same way as those in the standing position, as compared to the supine position. CONCLUSIONS: As such, sitting may not be the best position for older individuals in the assessment of their autonomic responses, whereas the supine position is recommended as the baseline posture in the old-age population. These findings are useful for future research in clinical settings that require accuracy in the ANS responses as determined by the HRV measurements.

Variation of Autonomic Nervous System Function by Age and Gender in Thai Ischemic Stroke Patients.

BACKGROUND: Ischemic stroke is one of the major causes of disability and mortality. Its effects on the autonomic nervous system (ANS) through nonlinear heart rate variability (HRV) and pulse transit time (PTT) have not been well explored among Thai patients. OBJECTIVE: This study aims to demonstrate the association between ANS and ischemic stroke through nonlinear HRV and PTT. METHODS: In total, 111 patients were enrolled in the study and their short-term HRV and PTT data were collected. RESULTS: Parasympathetic tone was higher in elderly patients (≥60 years). The elderly patients had a higher SD1 but lower SD2 and SD2/SD1 than the younger patients, and a similar pattern was found in the female patients compared to the male patients. These findings were supported by the results of the Poincaré plots. Older and female patients had circular plots and approximately round plots, respectively. Moreover, the parasympathetic nervous system (PNS) response was moderate and positively associated with SD1 (r = 0.47, p < 0.001) and PTT (r = 0.29, p = 0.002), and negatively associated with SD2 and SD2/SD1 (r = -0.47, p < 0.001), after controlling for age and sex. CONCLUSIONS: The PNS response was predominant in older and female patients whereas the sympathetic response was lower than in the younger and male patients, which reflected certain characteristics of ANS response to ischemic stroke. Moreover, nonlinear parameters of SD1, SD2, SD2/SD1, and Poincaré plots including PTT are useful and recommended in investigating ANS, particularly in PNS, among ischemic stroke patients.