Table 1.
Respiration, Heart Rate, and Heart Rate Variability Parameters
| Filtered Air | Diesel Exhaust Exposure With Exposure Mask | RM 1‐Way ANOVA P Value | |||||
|---|---|---|---|---|---|---|---|
| BL | Mask BL | 0–10 min | 10–20 min | 20–30 min | 30–40 min | ||
| Respiratory rate, breaths/min | 11.4 (9.8–13.1) | 10.2 (8.6–11.7) | 9.7 (8.3–11.1) | 10.6 (8.9–12.2) | 10.4 (9.0–11.8) | 10.8 (9.4–12.2) | 0.117 |
| Respiration depth, cyclic height, mV | 5.2 (4.1–6.2) | 5.4 (4.3–6.5) | 6.6 (4.9–8.3) | 6.2 (4.3–8.0) | 5.7 (4.4–7.0) | 6.0 (4.6–7.3) | 0.130* |
| Heart rate, beats/min | 64.3 (58.9–69.7) | 65.7 (60.2–71.3) | 66.7 (61.3–72.1) | 67.4 (61.5–72.1) | 67.2 (60.9–73.6) | 68.1 (62.2–74.0) | 0.001 |
| Systolic BP, mm Hg | 131.7 (126.4–136.9) | 127.6 (120.8–134.3) | 130.5 (124.7–136.3) | 132.7 (126.4–138.9) | 0.064 | ||
| Diastolic BP, mm Hg | 77.9 (74.6–81.3) | 74.5 (70.7–78.3) | 77.2 (73.1–81.3) | 76.9 (73.0–80.8) | 0.124 | ||
| Time domain | |||||||
| SDNN, ms | 58.1 (47.1–69.2) | 59.1 (48.6–69.6) | 67.6 (54.9–80.3) | 68.0 (52.7–83.3) | 67.4 (53.1–81.7) | 69.8 (53.0–86.7) | 0.047* |
| RMSSD, ms | 42.3 (31.5–53.1) | 42.1 (31.2–53.0) | 44.0 (33.1–54.9) | 42.8 (30.9–54.3) | 45.3 (30.9–59.7) | 43.7 (31.7–55.7) | 0.805* |
| Frequency domain | |||||||
| Total power, ms2 | 4417 (2524–6310) | 4348 (2348–63470) | 4900 (2982–6817) | 5383 (2588–8179) | 4892 (2979–6804) | 5839 (3106–8571) | 0.214* |
| VLF, ms2 | 1617 (554–2680) | 1613 (574–2653) | 1832 (754–2909) | 2536 (759–4313) | 1668 (934–2402) | 2273 (862–3685) | 0.601* |
| LF, ms2 | 1994 (1021–2966) | 1780 (844–2716) | 2201 (822–3580) | 1915 (936–2893) | 2057 (967–3147) | 2595 (811–4378) | 0.377* |
| HF, ms2 | 772 (440–1104) | 890 (392–1388) | 817 (430–1204) | 905 (501–1309) | 1095 (405–1785) | 942 (472–1412) | 0.444* |
| LF, nu | 68.5 (60.9–76.1) | 63.9 (51.3–76.6) | 68.0 (58.1–77.9) | 66.0 (58.7–73.3) | 63.2 (53.1–73.3) | 69.6 (60.5–78.8) | 0.537 |
| HF, nu | 30.9 (23.7–38.1) | 35.0 (23.3–46.7) | 31.9 (22.4–41.4) | 32.9 (25.8–40.1) | 35.3 (25.5–45.2) | 29.8 (21.0–38.7) | 0.684 |
| LF/HF ratio | 3.1 (1.7–4.5) | 3.2 (1.8–4.6) | 3.5 (1.8–5.3) | 2.7 (1.4–4.1) | 2.7 (1.4–4.0) | 3.7 (2.1–5.2) | 0.588 |
Values are presented as mean (95% CI). BL indicates baseline; BP, blood pressure; HF, high frequency; LF, low frequency; nu, normalized units; RM, repeated measures; RMSSD, root mean square of successive RR interval differences; SDNN, standard deviation of NN intervals; and VLF, very low frequency.
*
Statistical analysis performed on log values. RM 1‐way ANOVA, with Geisser‐Greenhouse correction, and Tukey’s multiple comparison test were performed unless otherwise stated.