Table 1.
Subject information across subgroups, with means and standard deviations (±std). Group effects were evaluated with parametric and Kruskal-Wallis ANOVA tests (four-group for age, BMI and psychological measures, and two-group for OSA parameters).
Figure 1.
Cold pressor heart rate responses.
A: 37 OSA and 57 control subjects; B: 6 OSA and 20 control female subjects, and 31 OSA and 37 control male subjects. Ai, Bi: Raw heart rate during the complete sequence. Aii, Bii, Biii: Change in heart rate relative to baseline (group mean ± SE), with time-points of significant increase or decrease relative to baseline within-group, and time-points of between-group differences (RMANOVA, p<0.05). Shaded areas indicate challenge periods.
Figure 2.
A: heart rate increase from baseline to initial peak (i); B: sustained heart rate elevation during mid-challenge period (area-under curve, ii); C: rate of change (slope) during mid-challenge increase (iii). Time trend graph illustrates the mean heart rate of the 57 subjects in the control group, with a simplified representation (thick black line) overlaid on the measured values (gray line). Shaded area indicates challenge period.
Table 2.
Statistics for mixed models implementing RMANOVA.
Table 3.
Indices for each challenge.
Figure 3.
Hand grip heart rate responses.
A: 37 OSA and 57 control subjects; B: 6 OSA and 20 control female subjects, and 31 OSA and 37 control male subjects. Aii, Bii: Raw heart rate during the complete sequence. Aii, Bii, Biii: Change in heart rate relative to baseline (group mean ± SE) averaged over 4 challenges, with time-points of significant increase or decrease relative to baseline within-group, and time-points of between-group differences (RMANOVA, p<0.05). Gray rectangles (hg) indicate challenge periods.
Figure 4.
A: heart rate increase from baseline to initial peak (i); B: sustained heart rate elevation during main challenge period (area-under curve, ii). Time trend graph illustrates the mean heart rate of the 57 subjects in the control group, with a simplified representation (thick black line) overlaid on the measured values (gray line). Shaded area indicates challenge period.
Figure 5.
Valsalva maneuver heart rate responses.
A: 37 OSA and 57 control subjects; B: 6 OSA and 20 control female subjects, and 31 OSA and 37 control male subjects. Ai, Bi, Raw heart rate and Aii load pressure during the complete sequence. Aiii,Bii, Biii: change in signals relative to baseline (group mean ± SE) averaged over 4 challenges, with time-points of significant increase or decrease relative to baseline within-group, and time-points of between-group differences (RMANOVA, p<0.05). Shaded areas (Val) indicate challenge periods.
Figure 6.
A: tachycardia ratio (TR; peak during i/baseline); B: heart rate increase from baseline to initial peak (i); C: Valsalva ratio (VR; peak during ii/minimum during recovery); D: rate of change (slope) during phase II increase (iii). Time-trend graph illustrates the mean heart rate of the 57 subjects in the control group, with a simplified representation (thick black line) overlaid on the measured values (gray line). Shaded area indicates challenge period.