Table 4:
Association Between mEMA Reported Substance Use and HRV Measures: Results of Multiple Regression Analysis
| LnRMSSD | LnLF/HF Ratio | |||||||
|---|---|---|---|---|---|---|---|---|
| Estimate (SE) | DF | t | P value | Estimate (SE) | DF | t | P value | |
| Intercept | 3.72 (0.21) | 66.6 | 17.89 | <.0001 | 0.34 (0.12) | 63.7 | 2.84 | .006 |
| Within Subject: | ||||||||
| Any Alcohol Use | −0.14 (0.05) | 1,646.2 | −2.83 | .005 | 0.14 (0.05) | 1,651.1 | 2.51 | .01 |
| Any nicotine use | 0.09 (0.09) | 1,643.8 | 0.97 | .33 | −0.08 (0.10) | 1,644.2 | −0.85 | .40 |
| Any marijuana use | 0.09 (0.08) | 1,644.6 | 1.16 | .24 | 0.05 (0.09) | 1,648.0 | 0.56 | .58 |
| Between Subject: | ||||||||
| Any Alcohol Use | −0.04 (0.44) | 62.7 | −0.09 | .93 | −0.08 (0.25) | 60.6 | −0.34 | .74 |
| Any nicotine use | −0.22 (0.19) | 61.2 | −1.15 | .26 | 0.04 (0.11) | 56.3 | 0.35 | .73 |
| Any marijuana use | −0.15 (0.44) | 65.0 | −0.34 | .74 | −0.10 (0.26) | 69.3 | −0.38 | .71 |
| Pregnant (vs Postpartum) | −0.02 (0.08) | 62.4 | −0.21 | .83 | −0.08 (0.05) | 58.9 | −1.77 | .08 |
| Age | 0.00 (0.01) | 67.4 | 0.00 | 1.00 | −0.01 (0.00) | 64.8 | −1.55 | .13 |
Ln – natural log transformation
RMSSD, root-mean square differences of successive N-N intervals
LF/HF ratio: LF - low frequency (0.04–0.15 Hz); HF - high frequency (0.15–0.40 Hz) spectral components of HRV