Table 1 Uni- and multi-variable mixed effects model of pulse rate and the various physiological phases and the potential confounders (showing estimated change in PR per covariate).

From: Pulse Rate Measurement During Sleep Using Wearable Sensors, and its Correlation with the Menstrual Cycle Phases, A Prospective Observational Study

Covariate Univariable model, estimated change in BPM (SE) Multivariable model#, estimated change in BPM (SE)
Menstrual phase
  Menstruation Reference Reference
 Ovulatory phase 2.09 (0.2)*** 2.19 (0.20)***
 Mid-luteal phase 3.81 (0.19)*** 4.05 (0.20)***
Alcohol§
 No alcohol Reference Reference
 1–4 units 1.56 (0.12)*** 2.11 (0.21)***
 5 or more units 5.90 (0.31)*** 8.27 (0.53)***
 Large meal§ (binary) 1.56 (0.18)*** 0.71 (0.28)*
Exercise§
 No exercise Reference Reference
 <60 minutes −0.21 (0.16) 0.05 (0.24)
  > = 60 minutes 0.48 (0.21)* 0.48 (0.30)
Body mass index (KG/M2) 0.70 (0.24)** 0.65 (0.24)**
Weight (KG)a 0.16 (0.08)*
Sex§ (binary) 0.10 (0.21)
Shower§, (binary) 0.30 (0.22)
Age (year) −0.09 (0.17)
Height (centimeter) −0.12 (0.13)
Coffee 0.36 (0.20)
  1. #Covariates not-included in the multivariable model are shown with a “—” in the table. §Within a four-hour period before sleep. Data available for participants with device 2 and 3 only. aGiven the collinearity between weight and body mass index, only body mass index was included in the multivariable model. *, **, *** refer to a p-value < 0.05, 0.01, 0.001, respectively.