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Table 4 Heart rate variability (HRV) at time points before and after unfiltered and filtered care rides

From: A controlled trial of acute effects of human exposure to traffic particles on pulmonary oxidative stress and heart rate variability

Out-come

Exposure

Mean (SD)

Mean of differences from pre-exposure (SD)

Pre-exposurea

Immediately Postb

6 hours posta

24 hours postc

Immediately Post

6 hours post

24 hours post

RMSSD (ms)

Filtered

0.095 (0.066)

0.103 (0.064)

0.064 (0.042)

0.082 (0.056)

0.008 (0.028)

−0.031 (0.043)

−0.011 (0.043)

Unfiltered

0.073 (0.048)

0.091 (0.051)

0.056 (0.033)

0.077 (0.059)

0.017 (0.050)

−0.016 (0.046)

0.077 (0.070)

P-value assessing exposure effect d

.5180

.91056

.9756

LF (ms2)

Filtered

1152.6 (1549.4)

1575.8 (1447.1)

623.1 (511.1)

933.5 (1045.4)

423.2 (1339.5)

−529.6 (1263.5)

−237.6 (1573.3)

Unfiltered

1112.2 (1005.2)

1432.9 (996.7)

752.9 (681.2)

827.9 (795.5)

281.3 (921.9)

−359.3 (733.0)

−284.0 (663.5)

P-value assessing exposure effect d

.3750

.2530

.7847

HF (ms2)

Filtered

2294.3 (3646.1)

2453.7 (2993.9)

1029.9 (1116.5)

1675.6 (2562.2)

159.4 (1232.4)

−1264.4 (3220.3)

−540.3 (2110.6)

Unfiltered

1908.1 (2922.2)

1882.6 (1996.0)

787.4 (768.2)

1613.0 (3191.2)

−94.3 (1853.6)

−1120.7 (2560.8)

−222.9 (1456.3)

P-value assessing exposure effect d

.2893

.2761

.6482

LF/HF (ms2)

Filtered

1.2 (1.6)

1.1 (0.9)

1.4 (1.2)

1.0 (0.6)

−0.1 (1.1)

0.3 (1.7)

−0.2 (1.6)

UnFiltered

1.2 (0.9)

1.3 (1.1)

1.3 (0.8)

1.1 (1.1)

0.1 (0.9)

0.1 (0.7)

−0.3 (0.7)

P-value assessing exposure effect d

.3263

.5061

.8774

Total Power (ms2)

Filtered

4644.2 (4699.9)

7879.1 (8187.1)

2699.3 (1975.1)

3891.0 (3658.0)

3234.9 (7109.1)

−1944.9 (4061.6)

−699.5 (3503.1)

Unfiltered

4391.9 (4976.9)

6338.7 (5207.0)

2948.1 (2513.4)

3652.7 (4980.4)

1828.7 (3700.2)

−1443.8 (3190.1)

−670.1 (3559.9)

P-value assessing exposure effect d

.2795

.4105

.9899

HR (min−1)

Filtered

60.1 (9.5)

56.8 (7.9)

68.9 (12.8)

61.3 (8.2)

−3.3 (5.0)

8.8 (8.5)

0.3 (6.8)

Unfiltered

61.4 (10.2)

59.4 (9.7)

70.2 (11.8)

63.3 (11.8)

−2.7 (7.9)

8.9 (9.3)

1.6 (6.8)

P-value assessing exposure effect d

.4087

.6640

.5514

  1. aN = 20 for filtered; N = 21 for unfiltered; bN = 20 for filtered and unfiltered; cN = 19 for filtered N = 21 for unfiltered; dDerived from mixed-effects linear model, controlling for baseline as a covariate and nested sessions within subject.
  2. Means and Standard Deviations of HRV outcomes at each time point, the changes from pre-exposure and p-values assessing the effect of exposure (unfiltered vs. HEPA-filtered ride) on change in HRV outcomes from pre-exposure baseline to post-exposure time points.