Influence of Insulin Resistance on the Association Between Physical Activity and Heart Rate Variability: The Toon Health Study
in Journal of Physical Activity and HealthBackground: Autonomic activity is possibly influenced by physical activity (PA). However, it remains unclear whether this association is modified by insulin resistance. Methods: This population-based study between 2009 and 2012 included 2016 men and women aged 30–79 years. The PA was assessed using a validated questionnaire based on sleep, occupation, transportation, household characteristics, and leisure-time PA. Heart rate (HR) and heart rate variability (HRV) in the sitting position were determined from 5-minute recordings of pulse waves detected by a fingertip sensor. The HRV was calculated as frequency (standard deviation of normal-to-normal [NN] intervals [SDNN]), root mean square of successive differences (RMSSD), and percentage differences between normal NN intervals >50 milliseconds [pNN50]) and time domains. Insulin resistance was evaluated using the homeostasis model assessment index (HOMA-IR). Results: HR, RMSSD, and pNN50 were related to the total and moderate/vigorous PA tertiles in models that included HOMA-IR. The partial regression coefficient of total PA per 1-SD increase was .05 (P = .019) for log-transformed RMSSD and 1.86 (P = .001) for pNN50. No interactive associations were observed between PA and HOMA-IR. Conclusions: Low total PA was associated with increased HR and low levels of RMSSD and pNN50, reflecting parasympathetic modulation that was not modified by insulin resistance.
Saito is with the Department of Public Health and Epidemiology, Faculty of Medicine, Oita University, Yufu, Oita, Japan. Maruyama is with the Department of Bioscience, Graduate School of Agriculture, Ehime University, Matsuyama, Japan. Kato is with the Center for Education and Educational Research, Faculty of Education, Ehime University, Matsuyama, Japan. Takata, Kawamura, and Osawa are with the Department of Diabetes and Molecular Genetics, Ehime University Graduate School of Medicine, Toon, Japan. Tomooka and Tanigawa are with the Department of Public Health, Juntendo University Graduate School of Medicine, Tokyo, Japan. Uesugi and Naito are with the Department of Food Science & Nutrition, School of Human Environmental Science, Mukogawa Women’s University, Hyogo, Japan.
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