A 50 Hz magnetic field affects hemodynamics, ECG and vascular endothelial function in healthy adults: A pilot randomized controlled trial

Figures

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  Fig 1. Flow chart of the study. The flow chart illustrates the basic layout of the clinical trial including steps involved in recruitment of study participants and the actual steps in the clinical trial of protocols A and B.

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  Fig 2. The time course of ulnar artery blood flow velocity (BFV) in forearm exposure to a 50 Hz MF. (A) Sham exposure. (B) MF exposure. (C) MF exposure - sham exposure. The duration of exposure is 15 min. The numbers indicate the individual identification numbers.

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  Fig 3. The time course of change rate (%) in ulnar artery blood flow velocity (BFV) in three different regional exposures to a 50 Hz MF. (A) Forearm exposure. (B) Upper arm exposure. (C) Neck exposure. The values are expressed as mean ± SD. n = 10 in each condition. The duration of exposure is 15 min. MF exposure, red closed circles; sham exposure, blue open circles. Two-way repeated-measures ANOVA, followed by the Student’s t-test or the Wilcoxon rank-sum test (between conditions), and the paired t-test or the Wilcoxon signed-rank test (within a condition). **p < 0.01 compared with the baseline (within a condition). #p < 0.05, ##p < 0.01, ###p < 0.001 compared with the time-matched sham exposure (between conditions).

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  Fig 4. The time course of the mean concentration (A) and change rate (B) of hemoglobin oxygenation index values of flexor carpi radialis muscles in the forearm exposure to a 50 Hz MF after muscle loading exercise. CH-1: Middle part of flexor carpi radialis muscles. CH-2: Proximal part of flexor carpi radialis muscles. Relative peak values were set at 1.0 (A). The values of 5-min exposure period were set at 100% (B). The values are expressed as mean ± SEM. n = 10 in each condition. The duration of exposure is 15 min. MF exposure, red closed circles; sham exposure, blue open circles. Two-way repeated-measures ANOVA, followed by the Student’s t-test or the Wilcoxon rank-sum test (between conditions), and the paired t-test or the Wilcoxon signed-rank test (within a condition). Values are expressed as mean ± SEM (n = 10 in each group). *p < 0.05, **p < 0.01, ***p < 0.001 compared with the baseline (within a group).

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  Fig 5. The time course of change rate (%) in ECG parameters in the neck exposure to a 50 Hz MF. (A) R-R interval (RRI) of heart rate variability. (B) High-frequency (HF) component. (C) Low-frequency/high-frequency (LF/HF) ratio. The values are expressed as mean ± SD. n = 10 in each condition. The duration of exposure is 15 min. MF exposure, red closed circles; sham exposure, blue open circles. Two-way repeated-measures ANOVA, followed by the Student’s t-test or the Wilcoxon rank-sum test (between conditions), and the paired t-test or the Wilcoxon signed-rank test (within a condition). *p < 0.05, **p < 0.01, ***p < 0.001 compared with the baseline (within a condition). #p < 0.05, ##p < 0.01 compared with the time-matched sham exposure (between conditions).

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  Fig 6. The time course of changes in FMD in the upper arm exposure to a 50 Hz MF. The duration of exposure is 30 min. MF exposure, red closed circles; sham exposure, blue open circles. Values are expressed as mean ± SD. n = 16 in each condition. Two-way repeated-measures ANOVA, followed by the Student’s t-test or the Wilcoxon rank-sum test (between conditions), and the paired t-test or the Wilcoxon signed-rank test (within a condition). *p < 0.05 compared with the baseline (within a condition). ##p < 0.01 compared with the time-matched sham exposure (between conditions).

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  Fig 7. Modeled distribution of the induced EFs in three different regional exposures to a 50 Hz MF. (A) Forearm exposure. (B) Upper arm exposure. (C) Neck exposure. The strength of the induced EFs is visualized at the depth of 2 mm below the skin surface.