Relationship between the median maternal respiratory rate and the number of synchronization epochs (SE) found per data set.

<p>Data points are shown separately for the Control (+) and Exercise (O) data, the regression line shown is calculated over all data points.</p

Number of synchronization epochs in the original and surrogate data sets, overall and in the various <i>n</i>:<i>m</i> combinations (corresponding percent values in parentheses).

<p>The surrogate absolute values have been divided by ten for comparison with the original values.</p><p>*distribution over <i>n</i>:<i>m</i> significantly different from Control (<i>p</i><0.001).</p><p>Number of synchronization epochs in the original and surrogate data sets, overall and in the various <i>n</i>:<i>m</i> combinations (corresponding percent values in parentheses).</p

Examples of the power spectral density (PSD) of a 24 h R-R interval series in a double logarithmic plot (decadic logarithm as indicated by ‘log₁₀’).

<p>The slope β denotes the slope of the linear regression calculated using the averaged PSD (grey circles; frequency range: 10⁻⁴ to 10⁻² Hz). Top: male subject, age 7.9 years; bottom: male subject, age 18.1 years.</p

Fetal and maternal mean RR interval duration, standard deviation (SDNN) and root mean square of successive differences (RMSSD) found in the subjects’ 18 min. data sets as well as in their synchronization epochs (SE).

<p>All values are given for the original data as well as the surrogate data, except for the 18 min. fetal data sets (only the maternal data sets were shuffled, see text). The values are compared between the Control and Exercise groups. <i>p</i>-values <0.05 in <b>bold type</b>.</p><p>n.a., not applicable.</p><p>Fetal and maternal mean RR interval duration, standard deviation (SDNN) and root mean square of successive differences (RMSSD) found in the subjects’ 18 min. data sets as well as in their synchronization epochs (SE).</p

Six minute synchrogram showing a 25 s episode of synchronization starting at 221 s with three fetal beats occurring within two maternal beats at constant phase values (<i>n</i>:<i>m</i> = 3:2).

<p>Six minute synchrogram showing a 25 s episode of synchronization starting at 221 s with three fetal beats occurring within two maternal beats at constant phase values (<i>n</i>:<i>m</i> = 3:2).</p

Relationship between the overall fetal-maternal variance (<i>Δq</i>) and the number of synchronization epochs (SE) found per data set.

<p>Data points are shown separately for the Control (+) and Exercise (O) data, the regression line shown is calculated over all data points.</p

Distribution of the synchronization epochs (SE) over the maternal beat phase <i>φ_mat-adj</i> in the original (top row) and surrogate data (bottom row) with respect to the <i>n</i>:<i>m</i> combinations 3:2, 4:3, 5:3 and 7:4.

<p>For the analysis, there were 10 surrogate data sets for each original; the histograms show the number of surrogate SE divided by 10 for comparability. <i>p</i>-values <0.10 for non-uniform distributions are given above the respective histograms, <i>p</i>-values <0.05 in <b>bold type</b>.</p

Course of the frequency domain measures during childhood and adolescence.

<p>HF – high frequency component, LF – low frequency component, VLF – very low frequency component, ULF – ultra low frequency component, ln ms² – natural logarithm of the absolute values in ms², ln LF/HF - natural logarithm of the ratio LF/HF. The circles represent 24 h averages. Solid and dashed lines show moving average and the fitted polynomial model of order 3, respectively.</p

Dependency of the number of SE found on fetal and maternal heart rate variability.

<p>SDNN: standard deviation, RMSSD: root mean square of successive differences, <i>Δq</i>: combined fetal-maternal variance, <i>r</i>: coefficient of correlation, <i>r²</i>: coefficient of determination. <i>p</i>_slope values <0.05 in <b>bold type</b>.</p><p>*except <i>Δq</i>.</p><p>Dependency of the number of SE found on fetal and maternal heart rate variability.</p

Comparison of different age groups with respect to scaling and complexity measures.

<p>Slope β – long-term fractal scaling properties, DFA α₂ – intermediate-term fractal scaling properties, DFA α₁ – short-term fractal scaling properties, ApEn - complexity. Each group shows three values: 24 h averages are plotted in black, night-time (left of black dot) and wake time averages (right of black dot) are plotted in grey. Note that the slope β can only be calculated for the entire recording. The symbol above a value/dot refers to comparisons within the same time period (24 h, night-time or wake time). * Group differed from 3 other groups. + Group differed from group <7 years and group 7 to 9 years. □ Group differed from group 7 to 9 years. ▵ Group differed from group 7 to 9 years and group 10 to 13 years.</p