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Table 1 Summary of physiological responses and variables from actigraphy

From: Effects of feet warming using bed socks on sleep quality and thermoregulatory responses in a cool environment

Variables No warming (CON) Feet warming P value
Sleep-onset latency [min] 16.0 ± 7.9 8.5 ± 7.8 0.018
Sleep efficiency [%] 86.2 ± 5.1 93.8 ± 5.1 0.047
Total sleep time [min] 362.0 ± 21.4 394.0 ± 21.6 0.047
Number of awakenings [times] 16.3 ± 4.9 8.8 ± 4.3 0.041
Total counts [times] 14,314 ± 3303 7926 ± 5497 0.056
Wake after sleep onset [min] 42.0 ± 20.4 17.5 ± 14.5 0.078
Average awakening length [min] 2.5 ± 1.0 1.8 ± 1.1 0.345
Movement index (MI)a [%] 14.52 ± 2.55 9.09 ± 5.20 0.079
Fragmentation index (FI)b [%] 11.07 ± 7.72 5.36 ± 9.41 0.328
Sleep fragmentation index (SFI)c [%] 25.59 ± 10.09 14.45 ± 9.36 0.134
Decreases in rectal temperature for 7-h sleep [°C] 0.63 ± 0.39 0.54 ± 0.31 0.427
Averaged mean skin temperature for 7-h sleep [°C] 35.1 ± 0.2 35.2 ±  0.3 0.660
Averaged distal-proximal skin temperature gradient (DPG) for 7-h sleep [°C] − 0.78 ± 0.56 − 0.19 ± 0.50 0.043
Insensible body mass loss for 7-h sleep [g h−1] 42.4 ± 16.7 52.6 ± 10.3 0.280
Increases in ankle skin temperature at 2.5 h [°C] 3.7 ± 2.6 4.8 ± 2.9 0.547
Averaged ankle skin temperature for 7-h sleep [°C] 33.6 ± 0.6 34.3 ± 0.4 0.003
Averaged foot skin temperature for 7-h sleep [°C] 34.2 ± 0.4 35.0 ± 0.2 0.012
Averaged hand skin temperature for 7-h sleep [°C] 34.4 ± 1.0 34.8 ± 0.7 0.287
Averaged heart rate [bpm] 61 ± 7 63 ± 6 0.245
  1. All data were expressed as mean ± SD
  2. aMI the percentage of periods with positive value in the y-axis counts during the sleep period
  3. bFI the percentage of 1 min periods of sleep versus the whole periods of sleep
  4. cSFI the sum of MI and FI (N = 6 except for the foot temperature [n = 5])
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