(PS6-B48) Myoelectric Gastric Activity and Heart Rate Variability Covariation During Inductions of Negative Emotionality and Repetitive Negative Thinking

Despite the connection between chronic emotional distress, disruptions in physiological processes, and negative health consequences (e.g., gastrointestinal symptoms, increased risk for cardiovascular disease), no studies have examined dynamic changes in myoelectric gastric activity and heart rate variability (HRV) during state negative emotionality (NE) and perseverative negative thinking (PNT). Thus, the current study examined dynamic changes in gastric activity (using electrogastrography [EGG]) and three metrics of HRV (mean square successive differences [MSD], root mean of squared successive differences [RMSSD], and respiratory sinus arrhythmia [RSA]) during laboratory inductions of NE and PNT in two diverse, undergraduate samples. In Study 1, 97 participants (37.1% White) viewed emotional film clips to induce fear and sadness. In Study 2, 30 participants (33.3% White) completed PNT (worry, rumination) inductions. Multilevel modeling (MLM) with restricted maximum likelihood method (REML) was used to explore covariation between EGG and HRV at baseline, during experimental inductions of NE and PNT, and during recovery periods. For baseline, fear, and fear recovery conditions, results revealed a significant main effect of condition on normogastria (F(2,182.13) = 6.63, p < .01, d = .34), such that normogastria was lower during fear compared to fear recovery (p < .01), and marginally lower during fear compared to baseline (p = .06). There were also significant condition by HRV interactions on normogastria (RSA: F(3,156.81) = 5.08, p < .01, d = .37; MSD: F(3,155.79) = 5.76, p < .001, d = .38; RMSSD: F(3,156.63) = 5.56, p < .01, d = .38), such that HRV and normogastria covaried during the fear condition (RSA: β = -.03, SE = .02, p</em> = .03, d = -.30; MSD: β = -.16, SE = .06, p = .01, d = -.36; RMSSD: β = -.07, SE = .03, p = .01, d = -.35), but not at baseline or during fear recovery (ps > .05). There were, however, no significant main or interaction effects for baseline, sadness, and sadness recovery conditions. For baseline, worry, and worry recovery conditions, there was a significant condition by RSA interaction on normogastria (F(3,54.54) = 5.28, p < .01, d = .62); normogastria and RSA marginally covaried during baseline and worry (βs = -.04, SEs = .02, ps = .06, ds = -.48 to -.47), but not during worry recovery (p = .36). There were also trending condition by HRV interactions on bradygastria (RSA: F(3,59.16) = 2.49, p = .07, d = .41; MSD: F(3,60.67) = 2.46, p = .07, d = .40; RMSSD: F(3,59.94) = 2.44, p = .07, d = .40), such that HRV and bradygastria covaried at baseline (βs = .02-.04, SEs = .01-.02, ps < .03, ds = .56-.57), during worry (βs = .03-.05, SEs = .01-.02, ps < .02, ds = .63), and during worry recovery (βs = .02-.05, SEs = .01-.02, ps = .02, ds = .51-.61). Lastly, there were no significant main or interaction effects for baseline, rumination, and rumination recovery conditions. Taken together, these findings demonstrate both similarities and differences in the patterns of covariance between EGG and HRV during laboratory inductions of NE and PNT. Limitations, future directions, and possible clinical implications will be discussed.