TABLE II.

Absolute values of the coefficients of nonlinear cardiorespiratory interactions corresponding to the last three base functions in (3), {x_r,x_c, $x_r^2{x}_c$,$x_r{x}_c^2$}. Coefficients {α_i} correspond to the respiration coupling to cardiac rhythm. Coefficients {β_i} correspond to the cardiac oscillation coupling to respiration. For each set of coefficients the actual values (top row) are compared with the mean inferred values obtained from 100 nonoverlapped 1 600 s blocks of data {x_r(t), x_c(t), y_r(t), y_c(t)}. Each block includes 160 000 points with a sampling time of 0.01 sec (middle row). The estimation error is shown in the bottom line.

α 20	β 20	α 21	β 21	α 22	β 22	D 11	D 22
0.12	2.20	0.048	0.27	−0.066	−8.67	0.18	8.13
0.12	2.41	0.048	0.28	−0.070	−8.61	0.18	8.14
2.9%	9.3%	1.8%	5.6%	5.2%	0.7%	0.2%	0.2%