Tanjaniina Laukkanen1, Jukka Lipponen2, Setor K Kunutsor3, Francesco Zaccardi4, Claudio Gil S Araújo5, Timo H Mäkikallio6, Hassan Khan7, Peter Willeit8, Earric Lee9, Sanna Poikonen10, Mika Tarvainen2, Jari A Laukkanen11. 1. Institute of Public Health and Clinical Nutrition, University of Eastern Finland, Kuopio, Finland; Central Finland Health Care District, Department of Internal Medicine, Jyväskylä, Finland. 2. Department of Applied Physics, University of Eastern Finland, Kuopio, Finland. 3. National Institute for Health Research Bristol Biomedical Research Centre, University Hospitals Bristol NHS Foundation Trust and University of Bristol, Bristol, UK; Musculoskeletal Research Unit, Translational Health Sciences, Bristol Medical School, University of Bristol, Learning & Research Building (Level 1), Southmead Hospital, Bristol, UK. 4. Diabetes Research Centre, Leicester General Hospital, University of Leicester, Leicester, UK. 5. Exercise Medicine Clinic, CLINIMEX, Rio de Janeiro, RJ, Brazil. 6. Division of Cardiology, Department of Internal Medicine, Oulu University Hospital, Oulu, Finland. 7. Department of Medicine, Division of Cardiology, Emory University, Atlanta, GA, United States. 8. Department of Neurology, Medical University Innsbruck, Innsbruck, Austria. 9. Faculty of Sport and Health Sciences, University of Jyväskylä, Jyväskylä, Finland. 10. Pihlajalinna Clinic, Jyväskylä, Finland. 11. Institute of Public Health and Clinical Nutrition, University of Eastern Finland, Kuopio, Finland; Central Finland Health Care District, Department of Internal Medicine, Jyväskylä, Finland; Faculty of Sport and Health Sciences, University of Jyväskylä, Jyväskylä, Finland. Electronic address: jari.a.laukkanen@jyu.fi.
Abstract
OBJECTIVE: Sauna bathing is becoming a common activity in many countries and it has been linked to favorable health outcomes. However, there is limited data on the heart rate (HR) and heart rate variability (HRV) responses to an acute sauna exposure. DESIGN: We conducted a single-group, longitudinal study utilizing a pre-post design to examine acute effects of sauna bathing on the autonomic nervous system as reflected by HRV. A total of 93 participants (mean [SD] age: 52.0 [8.8] years, 53.8% males) with cardiovascular risk factors were exposed to a single sauna session (duration: 30 min; temperature: 73 °C; humidity: 10-20%) and data on HRV variables were collected before, during and after sauna. RESULTS: Time and frequency-domain HRV variables were significantly modified (p < 0.001) by the single sauna session, with most of HRV variables tending to return near to baseline values after 30 min recovery. Resting HR was lower at the end of recovery (68/min) compared to pre-sauna (77/min). A sauna session transiently diminished the vagal component, whereas the cooling down period after sauna decreased low frequency power (p < 0.001) and increased high frequency power in HRV (p < 0.001), favorably modulating the autonomic nervous system balance. CONCLUSIONS: This study demonstrates that a session of sauna bathing induces an increase in HR. During the cooling down period from sauna bathing, HRV increased which indicates the dominant role of parasympathetic activity and decreased sympathetic activity of cardiac autonomic nervous system. Future randomized controlled studies are needed to show if HR and HRV changes underpins the long-term cardiovascular effects induced by regular sauna bathing.
OBJECTIVE: Sauna bathing is becoming a common activity in many countries and it has been linked to favorable health outcomes. However, there is limited data on the heart rate (HR) and heart rate variability (HRV) responses to an acute sauna exposure. DESIGN: We conducted a single-group, longitudinal study utilizing a pre-post design to examine acute effects of sauna bathing on the autonomic nervous system as reflected by HRV. A total of 93 participants (mean [SD] age: 52.0 [8.8] years, 53.8% males) with cardiovascular risk factors were exposed to a single sauna session (duration: 30 min; temperature: 73 °C; humidity: 10-20%) and data on HRV variables were collected before, during and after sauna. RESULTS: Time and frequency-domain HRV variables were significantly modified (p < 0.001) by the single sauna session, with most of HRV variables tending to return near to baseline values after 30 min recovery. Resting HR was lower at the end of recovery (68/min) compared to pre-sauna (77/min). A sauna session transiently diminished the vagal component, whereas the cooling down period after sauna decreased low frequency power (p < 0.001) and increased high frequency power in HRV (p < 0.001), favorably modulating the autonomic nervous system balance. CONCLUSIONS: This study demonstrates that a session of sauna bathing induces an increase in HR. During the cooling down period from sauna bathing, HRV increased which indicates the dominant role of parasympathetic activity and decreased sympathetic activity of cardiac autonomic nervous system. Future randomized controlled studies are needed to show if HR and HRV changes underpins the long-term cardiovascular effects induced by regular sauna bathing.
Authors: Jian Cui; Zhaohui Gao; Urs A Leuenberger; Cheryl Blaha; Jonathan Carter Luck; Michael D Herr; Lawrence I Sinoway Journal: J Appl Physiol (1985) Date: 2022-06-23