Table 2.
Baroreflex sensitivity and blood pressure variability before (baseline) and during cold exposure.
| Hypertensive (n = 24) | Controls (n = 17) | |||||
|---|---|---|---|---|---|---|
| Variable | Baseline(Median, Q1, Q3, or Mean, 95% CI) | Cold (Median, Q1, Q3, or Mean, 95% CI) | Difference (Median, Q1, Q3, or Mean, 95% CI) | Baseline (Median, Q1, Q3, or Mean, 95% CI) | Cold (Median, Q1, Q3, or Mean, 95% CI) | Difference (Median, Q1, Q3, or Mean, 95% CI) |
| LF BRS, ms/mmHg | 2.6 (2.0, 4.2) | 3.8 (2.5, 5.1)* | 0.7 (0.1, 2.2) | 4.3 (2.7, 5.0) | 4.4 (3.1, 7.1)* | 0.2 (−0.9, 2.9) |
| SBP SD, mmHg | 8.8 (8.3, 9.8) | 9.1 (7.2, 11.3) | 0.4 (−1.9, 2.1) | 6.8 (5.8, 8.0)** | 7.9 (7.1, 9.7)*,** | 1.5 (−0.4, 2.1)# |
| LF BPV, mmHg2 | 27 (19, 39) | 27 (19, 51) | 0 (−13, 20) | 13 (6, 18)** | 20 (13, 27)* | 8 (2, 14)# |
| HF BPV, mmHg2 | 7 (4, 9) | 10 (5, 21)* | 3 (−1, 9) | 4 (2, 8) | 8 (5, 9)* | 4 (0, 6) |
| LF RR, ms2 | 220 (130, 470) | 330 (170, 590)* | 110 (50, 290) | 120 (80, 370) | 280 (180, 1070)* | 140 (50, 470) |
| HF RR, ms2 | 30 (20, 70) | 80 (40, 210)* | 60 (20, 170) | 30 (20, 60) | 130 (70, 240)* | 90 (30, 200) |
| LF/HF ratio | 7.5 (3.0, 12.4) | 4.6 (2.4, 5.9)* | −2.2 (−6.6, −0.4) | 5.2 (2.3, 8.3) | 2.9 (2.2, 4.4)* | −1.3 (−3.4, 0.3) |
| HR, bpm | 83 (79–88) | 77 (72–82)* | −6 (−8–−4) | 77 (69–85) | 72 (65–78)* | −5 (−9–−1) |
| SBP, mmHg | 149 (143–154) | 178 (170–185)* | 29 (23–35) | 129 (123–135)** | 157 (149–165)*,** | 28 (21–34) |
| DBP, mmHg | 94 (90–97) | 105 (100–110)* | 11 (8–15) | 83 (77–88)** | 94 (88–99)*,** | 11 (8–14) |
Values are group medians and interquartile ranges (Q1, Q3) for skewed spectral estimates and group means and 95% confidence intervals for other parameters. Values were computed over 5 min phases in the end of baseline and cold exposure. In addition, the difference between cold and baseline is presented with medians and Q1, Q3, or means and 95% CI. BRS, baroreflex sensitivity; SBP, systolic blood pressure; SD, standard deviation; BPV, (systolic) blood pressure variability; LF, low frequency; HF, high frequency; RR, RR interval; HR, heart rate; DBP, diastolic blood pressure.
p < 0.05 vs. baseline (time),
p < 0.05 vs. hypertensive (group),
p < 0.05 vs. (cold-baseline) difference among hypertensive (interaction), assessed with Two-way repeated measures analysis of variance and contrast tests.