Herbert F Jelinek1,2, C Karmakar3, A M Kiviniemi4, A J Hautala4, M P Tulppo4, T H Mäkikallio5, H V Huikuri5, A H Khandoker3,6, M Palaniswami3. 1. Australian School of Advanced Medicine, Macquarie University, Sydney, Australia. hjelinek@csu.edu.au. 2. Centre for Research in Complex Systems and School of Community Health, Charles Sturt University, Albury, Australia. hjelinek@csu.edu.au. 3. Department of Electrical and Electronic Engineering, University of Melbourne, Melbourne, Australia. 4. Department of Exercise and Medical Physiology, Verve Research, Oulu, Finland. 5. Institute of Clinical Medicine, University of Oulu, Oulu, Finland. 6. Department of Biomedical Engineering, Khalifa University, Abu Dhabi, UAE.
Abstract
PURPOSE:Increased risk of arrhythmic events occurs at certain times during the circadian cycle with the highest risk being in the second and fourth quarter of the day. Exercise improves treatment outcome in individuals with cardiovascular disease. How different exercise protocols affect the circadian rhythm and the associated decrease in adverse cardiovascular risk over the circadian cycle has not been shown. METHODS:Fifty sedentary male participants were randomized into an 8-week high volume and moderate volume training and a control group. Heart rate was recorded using Polar Electronics and investigated with Cosinor analysis and by Poincaré plot derived features of SD1, SD2 and the complex correlation measure (CCM) at 1-h intervals over the 24-h period. RESULTS:Moderate exercise significantly increased vagal modulation and the temporal dynamics of the heart rate in the second quarter of the circadian cycle (p = 0.004 and p = 0.007 respectively). High volume exercise had a similar effect on vagal output (p = 0.003) and temporal dynamics (p = 0.003). Cosinor analysis confirms that the circadian heart rate displays a shift in the acrophage following moderate and high volume exercise from before waking (1st quarter) to after waking (2nd quarter of day). CONCLUSIONS: Our results suggest that exercise shifts vagal influence and increases temporal dynamics of the heart rate to the 2nd quarter of the day and suggest that this may be the underlying physiological change leading to a decrease in adverse arrhythmic events during this otherwise high-risk period.
RCT Entities:
PURPOSE: Increased risk of arrhythmic events occurs at certain times during the circadian cycle with the highest risk being in the second and fourth quarter of the day. Exercise improves treatment outcome in individuals with cardiovascular disease. How different exercise protocols affect the circadian rhythm and the associated decrease in adverse cardiovascular risk over the circadian cycle has not been shown. METHODS: Fifty sedentary male participants were randomized into an 8-week high volume and moderate volume training and a control group. Heart rate was recorded using Polar Electronics and investigated with Cosinor analysis and by Poincaré plot derived features of SD1, SD2 and the complex correlation measure (CCM) at 1-h intervals over the 24-h period. RESULTS: Moderate exercise significantly increased vagal modulation and the temporal dynamics of the heart rate in the second quarter of the circadian cycle (p = 0.004 and p = 0.007 respectively). High volume exercise had a similar effect on vagal output (p = 0.003) and temporal dynamics (p = 0.003). Cosinor analysis confirms that the circadian heart rate displays a shift in the acrophage following moderate and high volume exercise from before waking (1st quarter) to after waking (2nd quarter of day). CONCLUSIONS: Our results suggest that exercise shifts vagal influence and increases temporal dynamics of the heart rate to the 2nd quarter of the day and suggest that this may be the underlying physiological change leading to a decrease in adverse arrhythmic events during this otherwise high-risk period.
Authors: Jeffrey J Goldberger; Francis Kiet Le; Marc Lahiri; Prince J Kannankeril; Jason Ng; Alan H Kadish Journal: Am J Physiol Heart Circ Physiol Date: 2006-01-13 Impact factor: 4.733
Authors: Timo H Mäkikallio; Petra Barthel; Raphael Schneider; Axel Bauer; Jari M Tapanainen; Mikko P Tulppo; Juha S Perkiömäki; Georg Schmidt; Heikki V Huikuri Journal: Am J Cardiol Date: 2005-12-22 Impact factor: 2.778