Table 2.
Mean Differences in the Inflammatory Markers According to Quartiles of Daytime, Nighttime, and 24‐Hour HR
| HR Quartiles | P Value# | ||||
|---|---|---|---|---|---|
| First (n=96) Reference | Second (n=90) | Third (n=96) | Fourth (n=86) | ||
| Daytime HR, beats per min | 61±5 | 70±2 | 77±2 | 86±5 | |
| Leukocyte count×103/μL | 5.6±0.14 | 0.1±0.02 | 0.4±0.06 | 0.7±0.07a | .02 |
| Platelet count×103/μL | 223±5.8 | 7±−0.7 | 28±0.1a | 23±0.1a | .003 |
| CRP, mg/L | 2.3±0.34 | 0.3±−0.02 | 1.4±0.17 | 0.6±0.03 | .07 |
| 25[OH]D, ng/mL | 31.1±1.23 | −1.9±−0.11 | −2.7±−0.09 | −1.7±−0.05 | .42 |
| Nighttime HR, beats per min | 53±4 | 61±2 | 67±2 | 76±5 | |
| Leukocyte count×103/μL | 5.5±0.14 | 0.3±0.02 | 0.3±0.01 | 1.2±0.07a , b , c | <.001 |
| Platelet count×103/μL | 226±5.6 | 7±0.1 | 15±0.1 | 25±1.8a | .03 |
| CRP, mg/L | 1.9±0.26 | 1.0±0.16 | 0.8±−0.01 | 1.9±0.29a | .005 |
| 25[OH]D, ng/mL | 32.4±1.19 | −3.9±−0.02 | −2.6±−0.01 | −4.8±−0.04a | .02 |
| 24‐h HR, beats per min | 60±4 | 68±2 | 74±2 | 84±5 | |
| Leukocyte count×103/μL | 5.5±0.13 | 0.3±0.03 | 0.5±0.03 | 0.8±0.08a | .01 |
| Platelet count×103/μL | 222±6.0 | 12±−0.7 | 27±−0.1a | 24±1.3a | .007 |
| CRP, mg/L | 2.3±0.35 | 0.2±−0.04 | 1.2±0.08 | 0.6±0.04 | .09 |
| 25[OH]D, ng/mL | 31.8±1.15 | −2.5±0.16 | −3.4±−0.12 | −2.8±0.07 | .16 |
Abbreviations: 25[OH]D, 25‐hydroxyvitamin D; CRP, C‐reactive protein. Differences shown for inflammatory markers are vs the first quartile of heart rate measures (reference). Values are reported as mean±standard deviation for heart rate (HR) measures and mean±standard error for the inflammatory markers. # P values were determined using analysis of variance. a P<.05 vs the first quartile. b P<.05 vs the second quartile. c P<.05 vs the third quartile.