Table 5 Summary of Between-condition Linear Mixed Model Effects for Nightly Physiological Outcomes.

From: A semi-randomised control trial assessing psychophysiological effects of breathwork and cold immersion

Comparison

Resting Heart Rate

Heart Rate Variability

Respiratory Rate

Sleep Quantity

Slow Wave Sleep

Rapid Eye Movement Sleep

 

Estimate (SE)

[95% Confidence Interval]

Intercept

(MC)

4.07 (0.01) [4.05, 4.09]***

3.89 (0.04) [3.81, 2.96]***

15.30 (0.13) [15.04, 15.56]***

7.16 (0.06) [7.03, 7.28]***

1.50 (0.02) [1.44, 1.54]***

1.72 (0.04) [1.64, 1.80]***

WHM (vs MC)

0.01 (0.02) [-0.02, 0.05]

-0.02 (0.05) [-0.12, 0.08]

0.29 (0.18) [-0.06, 0.65]

-0.10 (0.09) [-0.27, 0.08]

0.01 (0.03) [-0.10, 0.07]

-0.03 (0.06) [-0.14, 0.09]

WHM-remote

(vs MC)

-0.02 (0.02) [-0.05, 0.01]

-0.03 (0.05) [-0.14, 0.07]

-0.38 (0.19) [-0.75, -0.02]*

-0.20 (0.09) [-0.37, -0.02]*

0.05 (0.04) [-0.02, 0.12]

0.01 (0.06) [-0.11, 0.12]

WHM-remote

(vs WHM)*

-0.03 (0.02) [-0.065, -0.003]*

-0.01 (0.05) [-0.11, 0.09]

-0.68 (0.18) [-1.04, -0.32]***

-0.10 (0.09) [-0.27, 0.07]

0.04 (0.03) [-0.03, 0.11]

0.03 (0.06) [-0.10, 0.15]

Days on Protocol

-0.0002 (0.002) [-0.0006, 0.0002]

0.001 (0.001) [-0.0001, 0.0025]

0.003 (0.001) [-0.0004, 0.0054]

-0.003 (0.003) [-0.009, 0.003]

-0.001 (0.001) [-0.003, 0.002]

-0.001 (0.002) [-0.004, 0.002]

WHM* Days on Protocol

-0.0004 (0.003) [-0.0010, 0.0002]

0002 (0.001) [-0.002, 0.002]

-0.01 (0.002) [-0.009, -0.001]*

0.002 (0.005) [-0.01, 0.01]

0.0002 (0.002) [-0.003, 0.003]

0.001 (0.002) [-0.003, 0.01]

WHM-remote* Days on Protocol

0.0004 (0.0003) [-0.0001, 0.0009]

-0.001 (0.001) [-0.003, 0.001]

-0.001 (0.002) [-0.005, 0.003]

0.01 (0.004) [-0.004, 0.014]

0.001 (0.001) [-0.002, 0.004]

-0.001 (0.002) [-0.006, 0.002]

  1. Estimates are unstandardised; SE = standard error; heart rate variability and resting heart rate = log transformed; WHM = Wim Hof Method in-person; WHM-remote = Wim Hof Method remote; MC = Meditation control. WHM-remote vs WHM* results were obtained from a follow-up LMM with WHM as the reference level.
  2. ​​*p < 0.05. **p < 0.01. ***p < 0.001.