Short‐term effects of weight‐loading on heart rate variability in obese adults

Figures

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  FIGURE 1. Schematic overview of the trial and HRV measurements timeline. Screening performed on Day −21. Baseline 24‐h ECG at Day −13 (Baseline HRV). Randomization on Day 0 to either Low‐load (n = 26) or High‐load (n = 25) vest use for 35 days. A second 24‐h ECG was obtained on Day 15 (Intervention HRV). HRV was analyzed over the full 24‐h period and during the four 1‐h periods (morning, afternoon, evening, night). Figure created in BioRender.com with publication rights. ECG, electrocardiography; HRV, Heart Rate Variability.

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  FIGURE 2. Changes in heart rate and time domain HRV parameters from baseline in the low‐load (n = 26) and high‐load (n = 20–23) groups. Panels show changes in (a) heart rate, (b) relative HRR (%HRR), (c) SDNN, and (d) RMSSD across four time periods (morning, afternoon, evening, night). The high‐load intervention increased %HRR and reduced SDNN and RMSSD during the afternoon. Box plots display medians (lines), interquartile ranges (boxes), whiskers (Tukey's method), and outliers (points). Abbreviations are provided as shown in Table 1.

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  FIGURE 3. Changes in frequency domain HRV parameters from baseline in the low‐load (n = 25) and high‐load (n = 20–24) groups. Panels show changes in (a) total power spectral density (PTotal), (b) normalized high‐frequency power (HFn.u.), (c) normalized low‐frequency power (LFn.u.), and (d) the LFn.u./HFn.u. ratio across four time periods (morning, afternoon, evening, night). Total power was significantly lower in the high‐load group during the afternoon. Box plots show medians (lines), interquartile ranges (boxes), whiskers (Tukey's method), and outliers (points). Abbreviations are provided as shown in Table 1.

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  FIGURE 4. Changes in heart rate and %HRR from baseline in females and males. Panels show changes in heart rate (a, c) and %HRR (b, d) across four time periods (morning, afternoon, evening, night) in females (a, b; low‐load n = 13, high‐load n = 11–13) and males (c, d; low‐load n = 13, high‐load n = 9–11). Gray bars represent the low‐load group; red bars represent the high‐load group in females and blue bars represent the high‐load group in males. In females, the high‐load group showed increased afternoon heart rate and %HRR compared with low load. Box plots show medians (lines), interquartile ranges (boxes), whiskers (Tukey's method), and outliers (points). Abbreviations are provided as shown in Table 1.

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  FIGURE 5. Changes in frequency domain HRV parameters from baseline in females and males. Panels show changes in normalized high‐frequency power (HFn.u.), normalized low‐frequency power (LFn.u.), and the LFn.u./HFn.u. ratio across four time periods (morning, afternoon, evening, night) in females (a–c; low‐load n = 13, high‐load n = 10–13) and males (d–f; low‐load n = 12, high‐load n = 9–11). Gray bars represent the low‐load group; red bars represent the high‐load group in females and blue bars represent the high‐load group in males. In females, the high‐load group showed reduced HFn.u., increased LFn.u., and a higher LFn.u./HFn.u. ratio in the afternoon compared with low load. Box plots show medians (lines), interquartile ranges (boxes), whiskers (Tukey's method), and outliers (points). Abbreviations are provided as shown in Table 1.