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Effects of posture and acute sleep deprivation on heart rate variability.

Nam KC, Kwon MK, Kim DW - Yonsei Med. J. (2011)

Bottom Line: The number of sleep deprivation occurrences in the sitting posture was significantly less than that in the recumbent posture (p<0.01), resulting in smaller increase of LFP/HFP.A sitting posture is preferable to a recumbent posture for analyzing HRV, because of decreased drowsiness and sleep deprivation, thereby decreasing variation of LFP/HFP during experiment.Considering the drowsiness, it is also recommended that any experiment should be completed within 15 minutes, if possible.

View Article: PubMed Central - PubMed

Affiliation: Department of Medical Engineering, Yonsei University College of Medicine, 250 Seongsan-ro, Seodaemun-gu, Seoul 120-752, Korea.

ABSTRACT

Purpose: In our previous study to investigate autonomic nervous system (ANS) activity due to radio frequency (RF) radiation using heart rate variability (HRV), drowsiness was observed in approximately half of all subjects. Therefore, the usage of HRV with unwanted drowsiness could falsely indicate the effects of RF radiation by mobile phones on the ANS. The objective of this study was to determine which posture is appropriate for accurate HRV analysis for provocation study.

Materials and methods: A total of 52 healthy subjects (25 males and 27 females) participated in this experiment. We measured the number of times a subject showed drowsiness or sleep deprivation due to awakening, and analyzed HRV six times over 30 minutes in sitting and recumbent postures, using power spectrum.

Results: We employed the ratio of low frequency power to high frequency power (LFP/HFP) to analyze the changes in the ANS. The number of sleep deprivation occurrences in the sitting posture was significantly less than that in the recumbent posture (p<0.01), resulting in smaller increase of LFP/HFP. Although LFP/HFP of the two postures varied with time without any provocation, it was more stable in sitting than in recumbent postures.

Conclusion: A sitting posture is preferable to a recumbent posture for analyzing HRV, because of decreased drowsiness and sleep deprivation, thereby decreasing variation of LFP/HFP during experiment. Considering the drowsiness, it is also recommended that any experiment should be completed within 15 minutes, if possible.

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Relative changes (%) in LFP/HFP of sitting and recumbent postures for each stage, which lasted for five minutes. The * and ** indicate statistically significant changes between stage 1 and other stages for sitting and recumbent postures.
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Figure 1: Relative changes (%) in LFP/HFP of sitting and recumbent postures for each stage, which lasted for five minutes. The * and ** indicate statistically significant changes between stage 1 and other stages for sitting and recumbent postures.

Mentions: Repeated measures ANOVA showed that LFP/HFP was significantly dependent on the posture (p=0.033). Fig. 1 shows mean±SE of LFP/HFP in sitting and recumbent postures for six stages with 52 subjects. It should be noted that LFP/HFP ratios in each stage of the sitting posture were smaller than those in each stage of the recumbent posture, suggesting that a sitting posture is better than a recumbent posture. This increased trend in LFP/HFP for the recumbent posture confirmed a previous report showing that sleep deprivation could increase LFP and LFP/HFP.5


Effects of posture and acute sleep deprivation on heart rate variability.

Nam KC, Kwon MK, Kim DW - Yonsei Med. J. (2011)

Relative changes (%) in LFP/HFP of sitting and recumbent postures for each stage, which lasted for five minutes. The * and ** indicate statistically significant changes between stage 1 and other stages for sitting and recumbent postures.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3104443&req=5

Figure 1: Relative changes (%) in LFP/HFP of sitting and recumbent postures for each stage, which lasted for five minutes. The * and ** indicate statistically significant changes between stage 1 and other stages for sitting and recumbent postures.
Mentions: Repeated measures ANOVA showed that LFP/HFP was significantly dependent on the posture (p=0.033). Fig. 1 shows mean±SE of LFP/HFP in sitting and recumbent postures for six stages with 52 subjects. It should be noted that LFP/HFP ratios in each stage of the sitting posture were smaller than those in each stage of the recumbent posture, suggesting that a sitting posture is better than a recumbent posture. This increased trend in LFP/HFP for the recumbent posture confirmed a previous report showing that sleep deprivation could increase LFP and LFP/HFP.5

Bottom Line: The number of sleep deprivation occurrences in the sitting posture was significantly less than that in the recumbent posture (p<0.01), resulting in smaller increase of LFP/HFP.A sitting posture is preferable to a recumbent posture for analyzing HRV, because of decreased drowsiness and sleep deprivation, thereby decreasing variation of LFP/HFP during experiment.Considering the drowsiness, it is also recommended that any experiment should be completed within 15 minutes, if possible.

View Article: PubMed Central - PubMed

Affiliation: Department of Medical Engineering, Yonsei University College of Medicine, 250 Seongsan-ro, Seodaemun-gu, Seoul 120-752, Korea.

ABSTRACT

Purpose: In our previous study to investigate autonomic nervous system (ANS) activity due to radio frequency (RF) radiation using heart rate variability (HRV), drowsiness was observed in approximately half of all subjects. Therefore, the usage of HRV with unwanted drowsiness could falsely indicate the effects of RF radiation by mobile phones on the ANS. The objective of this study was to determine which posture is appropriate for accurate HRV analysis for provocation study.

Materials and methods: A total of 52 healthy subjects (25 males and 27 females) participated in this experiment. We measured the number of times a subject showed drowsiness or sleep deprivation due to awakening, and analyzed HRV six times over 30 minutes in sitting and recumbent postures, using power spectrum.

Results: We employed the ratio of low frequency power to high frequency power (LFP/HFP) to analyze the changes in the ANS. The number of sleep deprivation occurrences in the sitting posture was significantly less than that in the recumbent posture (p<0.01), resulting in smaller increase of LFP/HFP. Although LFP/HFP of the two postures varied with time without any provocation, it was more stable in sitting than in recumbent postures.

Conclusion: A sitting posture is preferable to a recumbent posture for analyzing HRV, because of decreased drowsiness and sleep deprivation, thereby decreasing variation of LFP/HFP during experiment. Considering the drowsiness, it is also recommended that any experiment should be completed within 15 minutes, if possible.

Show MeSH