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Table 2 Percent change (95% confidence interval) in outcome levels estimated by mixed effects model adjusted for sex and body mass index

From: Cardiovascular health effects following exposure of human volunteers during fire extinction exercises

Outcome Exposure vs Before Exposure vs After After vs Before Exposure vs Unexposeda
RHI b −21.9 (−32.0,-10.3)*** −14.3 (−25.3, −1.6)** −8.9 (−20.7, 4.6) −18.0 (−26.0, −9.2)***
SDNNb −17.3 (−28.3, −6.4)** −10.3 (−21.7, 1.2) −7.9 (−18.9, 3.1) −13.2 (−22.9, −3.6)**
pNN50b −36.1 (−52.3, −19.9)*** −25.1 (−43.4, −6.8)** −14.7 (−31.0, 1.6) −28.6 (−45.3, −11.8)***
RMSSDb −26.9 (−41.0, −12.7)*** −18.6 (−33.9, −3.4)* −10.2 (−24.4, 4.1) −21.5 (−33.4, −9.7)***
LFb 27.0 (11.3, 42.8)*** 17.8 (3.7, 31.9)* 7.8 (−8.1, 23.7) 21.1 (7.9, 34.2)**
HFb −15.4 (−26.2, −4.7)** −4.4 (−16.1, 7.4) −11.6 (−22.4, −0.7)* −9.1 (−19.2, 1.0)
LF/HFb 41.4 (15.0, 67.9)** 17.1 (−3.9, 38.2) 20.7 (−6.0, 47.4) 26.4 (6.7, 46.2)**
SP −4.4 (−8.0, −0.7)* −0.3 (−4.2, 3.5) −4.0 (−7.7, −0.3)* −2.4 (−5.7, 1.0)
DP −3.2 (−8.6, 2.3) 5.8 (−0.2, 11.8) −8.5 (−14.0, −3.0)** 1.1 (−3.5, 5.7)
AI.75 −8.8 (−24.8, 7.3) −15.3 (−30.2, −0.4)* 7.7 (−8.3, 23.8) −12.2 (−26.4, 2.1)
BL.HR 12.7 (9.0, 16.3)*** 9.4 (5.8, 12.9)*** 3.0 (−0.7, 6.7) 11.0 (7.7, 14.3)***
  1. RHI reactive hyperemia index, SDNN standard deviation of all NN intervals, pNN50 proportion of successive NN intervals differing by more than 50 milliseconds divided by total number of NN intervals, RMSSD square root of the mean squared differences of successive NN intervals, LF power in low frequency range (0.04–0.15 Hz) in ms2, HF power in high frequency range (0.15–0.4 Hz) in ms2, LF/HF ratio LF(ms2)/HF(ms2), SP systolic blood pressure (mmHg), DP diastolic blood pressure (mmHg), AI.75 augmentation index corrected for 75 bpm, BL.HR baseline heart rate (bpm)
  2. Results are percent change from the mixed effect model in Fig. 1 except for RHI where percent change was obtained directly from the effect estimate due to the logarithmic transformation. The data are based on 43 individuals with measurements in both fire extinction exercise and control exposure condition (measurements of control exposure condition were missing for one subject in RHI and heart rate variability outcomes)
  3. *,**,*** Significantly different (p < 0.05, p < 0.01 and p < 0.001 respectively)
  4. a Unexposed corresponds to the mean between “Before” and “After” for each subject
  5. b One subject was eliminated due to missing data in both control measurements