Table 1.
Correlations with ln-transformed HRV |
||||
---|---|---|---|---|
Variable | Mean (SD) or n (%) | SDRR | RMSSD | HF-HRV |
Demographics | ||||
Age, years | 57.39 (11.34) | −0.32*** | −0.21*** | −0.28*** |
Male | 391 (43.01%) | 0.06† | −0.01 | −0.06† |
White race (vs. Non-White) | 733 (80.64%) | −0.07* | −0.19*** | −0.22*** |
Household income, median (Q1 - Q3) | $59,500 ($30,650 - $96,250) | 0.06† | −0.05 | −0.03 |
Physical Health Covariates | ||||
Body mass index, kg/m2 | 29.63 (6.40) | −0.07* | −0.00 | 0.01 |
Number of comorbid conditions | 4.02 (2.91) | −0.22*** | −0.10** | −0.12*** |
Medication use | ||||
Cholesterol-lowering | 252 (27.72%) | −0.18*** | −0.12*** | −0.15*** |
Corticosteroid | 37 (4.07%) | −0.07* | −0.06† | −0.05 |
Blood pressure | 316 (34.76%) | −0.19*** | −0.03 | −0.05 |
Health Behaviors from Clinic Visit | ||||
Physical activity, 20+ min 3x/week | 702 (77.23%) | 0.03 | −0.02 | 0.007 |
Cigarette smoking status | ||||
Never smoked | 483 (53.14%) | 0.04 | −0.02 | 0.00 |
Former smoker | 301 (33.11%) | −0.12*** | −0.08* | −0.10** |
Current smoker | 125 (13.75%) | 0.11*** | 0.14*** | 0.14*** |
Health Behaviors from Daily Interviews | ||||
Daily physical activity, minutes | 41.32 (57.64) | 0.05 | 0.02 | 0.01 |
Daily cigarettes smoked (n = 895) | 1.74 (5.19) | 0.06† | 0.09** | 0.10** |
Daily Stress Processes a | ||||
Daily negative affect (range: 0-4) | 0.21 (0.27) | −0.06† | −0.06† | −0.07* |
Stressor frequency (% stressor days) | 42.48% (26.35%) | −0.01 | −0.04 | −0.04 |
Stressor severity (n = 846)b | 1.74 (0.65) | −0.10** | −0.09* | −0.08* |
Affective reactivity (n = 807)c | 0.17 (0.12) | −0.08* | −0.07* | −0.08* |
Heart Rate Variability (ln-transformed) | ||||
SD of RR intervals, ms | 3.46 (0.47) | --- | 0.83*** | 0.80*** |
RMS successive RR differences, ms | 2.91 (0.63) | --- | --- | 0.96*** |
High frequency (0.15-0.50 Hz), ms2 | 4.89 (1.29) | --- | --- | --- |
p ≤ 0.001,
p ≤ 0.01,
p ≤ 0.05,
p ≤ 0.10
Correlations between daily stress processes and HRV were partialed for age, income, and race, due to strong confounding relationships of demographics with stress and HRV.
Participants rated how stressful each event was, using a 0 (not at all) to 3 (very) scale. Seven percent of the sample (n = 63) did not experience a stressor during the 8 days of interviews.
Affective reactivity was defined as the change in negative affect on a stressor day, compared to a nonstressor day. Affective reactivity was not computed for 102 participants (63 did not have a stressor; 39 had stressors every day).