Effect of different set configurations on heart rate variability, blood pressure, and metabolic response following a full‑body resistance training session

Abstract

Abstract Background Set configuration, the manipulation of sets, repetitions, and rest intervals in resistance exercise, can influence physiological responses. Evidence suggests set configuration may impact cardiac autonomic function, potentially reducing parasympathetic activity. This study examined the effects of short, long, and very short set configurations on heart rate variability (Root Mean Square of Successive Differences (RMSSD), Standard Deviation of Normal-to-Normal Intervals (SDNN), Percentage of Successive RR Intervals Differing by More Than 50 ms (PN50), LF, HF, LF/HF), blood pressure, and lactate dehydrogenase levels after a full-body resistance training session. Hypothesis Resistance exercise with different set configurations would induce comparable effects on cardiovascular and metabolic indices compared to a traditional resistance training approach, with VSSC potentially minimizing parasympathetic withdrawal. Study design Experimental study—between-groups design. Methods Forty-eight healthy women (20–35 years) were randomized into four groups: a control group, a long set configuration group (LSC: 4 sets of 12 repetitions at 80% of maximum, 2 min rest between sets, 3 min between exercises), a short set configuration group (SSC: 8 sets of 6 repetitions at 40% of maximum, 51 s rest), and a very short set configuration group (VSSC: 12 sets of 4 repetitions at 26% of maximum, 32 s rest). Results The very short set configuration significantly increased the RMSSD index, a marker of parasympathetic activity, compared to the long (p = 0.043) and short (p = 0.019) set configurations (F = 4.009, η2 = 0.25) . No significant differences were observed in SDNN and PN50 indices among the configurations post-exercise. The long set configuration significantly increased lactate dehydrogenase levels (F = 3.61, p = 0.02, η2 = 0.22) compared to the short (p = 0.044) and control (p = 0.031) groups. Both long (p = 0.024) and short (p = 0.029) set configurations significantly reduced systolic blood pressure (SBP) (F = 4.003, p = 0.01, η2 = 0.24) compared to the control group. Conclusions The use of very short set configurations is recommended as a potentially safe resistance training method from a cardiac perspective. However, caution is advised when extrapolating these findings to high-risk populations. Clinical relevance Very short set configurations offer a potentially safer resistance training approach for promoting cardiac parasympathetic balance and minimizing lactate dehydrogenase increases. These findings can inform personalized training programs.