Normative references of heart rate variability and salivary alpha-amylase in a healthy young male population

<p>Abstract</p> <p>Background</p> <p>This study aimed to present normative reference values of heart rate variability and salivary alpha-amylase in a healthy young male population with a particular focus on their distribution and reproducibility.</p> <p>Methods</p> <p>The short-term heart rate variability of 417 young healthy Japanese men was studied. Furthermore, salivary alpha-amylase was measured in 430 men. The average age of the subjects were 21.9 years with standard deviation of 1.6 years. Interindividual variations in heart rate variability indices and salivary alpha-amylase levels were plotted as histograms. Data are presented as the mean, median, standard deviation, coefficient of variation, skewness, kurtosis, and fifth and 95th percentiles of each physiological index.</p> <p>Results</p> <p>Mean recorded values were heart period 945.85 ms, log-transformed high frequency component 9.84 ln-ms², log-transformed low frequency component 10.42 ln-ms², log-transformed low frequency to high frequency ratio 0.58 ln-ratio, standard deviation of beat-to-beat interval 27.17 ms and root mean square of successive difference 37.49 ms. The mean value of raw salivary alpha-amylase was 17.48 U/mL, square root salivary alpha-amylase 3.96 sqrt[U/mL] and log-transformed salivary alpha-amylase 2.65 ln[U/mL]. Log-transformed heart rate variability indices exhibited almost symmetrical distributions; however, time-domain indices of heart rate variability (standard deviation of beat-to-beat interval and root mean square of successive difference) exhibited right-skewed (positive skewness) distributions. A considerable right-skewed distribution was observed for raw salivary alpha-amylase. Logarithmic transformation improved the distribution of salivary alpha-amylase, although square root transformation was insufficient. The day-to-day reproducibility of these indices was assessed using intraclass correlation coefficients. Intraclass correlation coefficients of most heart rate variability and salivary indices were approximately 0.5 to 0.6. Intraclass correlation coefficients of raw salivary markers were approximately 0.6, which was similar to those of heart rate variability; however, log transformation of the salivary markers did not considerably improve their reproducibility. Correlations between sympathetic indicators of heart rate variability and salivary alpha-amylase were not observed.</p> <p>Conclusion</p> <p>Because the sample population examined in this study involved limited age and gender variations, the present results were independent of these factors and were indicative of pure interindividual variation.</p

Heart Rate Variability Characteristics in Sedentary Postmenopausal Women Following Six Months of Exercise Training: The DREW Study

Article on heart rate variability characteristics in sedentary postmenopausal women following six months of exercise training

Effect of exercise on cardiac autonomic function in females with rheumatoid arthritis

The objective of this study is to evaluate the effect of exercise on cardiac autonomic function as measured by short-term heart rate variability (HRV) in females suffering from rheumatoid arthritis (RA). Females with confirmed RA were randomly assigned to an exercise group (RAE) and a sedentary group (RAC). RAE was required to train under supervision two to three times per week, for 3 months. Three techniques (time domain, frequency domain and Poincaré plot analyses) were used to measure HRV at baseline and study completion. At baseline, RAC (n018) had a significantly higher variability compared to RAE (n019) for most HRV indicators. At study completion, the variables showing significant changes (p00.01 to 0.05) favoured RAE in all instances. Wilcoxon signed rank tests were performed to assess changes within groups from start to end. RAE showed significant improvement for most of the standing variables, including measurements of combined autonomic influence, e.g. SDRR (p00.002) and variables indicating only vagal influence, e.g. pNN50 (p00.014). RAC mostly deteriorated with emphasis on variables measuring vagal influence (RMSSD, pNN50, SD1 and HF (ms2)). Study results indicated that 12 weeks of exercise intervention had a positive effect on cardiac autonomic function as measured by short-term HRV, in females with RA. Several of the standing variables indicated improved vagal influence on the heart rate. Exercise can thus potentially be used as an instrument to improve cardiac health in a patient group known for increased cardiac morbidity.http://www.springerlink.com/content/102818