Speed- and Circuit-Based High-Intensity Interval Training on Recovery Oxygen Consumption

Original Research Speed- and Circuit-Based High-Intensity Interval Training on Recovery Oxygen Consumption LINDSAY N. SCHLEPPENBACH*, ANDREAS B. EZER*, SARAH A. GRONEMUS*, KATELYN R. WIDENSKI*, SAORI I. BRAUN‡, JEFFREY M. JANOT‡ Department of Kinesiology, University of Wisconsin-Eau Claire, Eau Claire, WI, USA *Denotes undergraduate student author, ‡Denotes professional author ABSTRACT International Journal of Exercise Science 10(7): 942-953, 2017. Due to the current obesity epidemic in the United States, there is growing interest in efficient, effective ways to increase energy expenditure and weight loss. Research has shown that high-intensity exercise elicits a higher Excess Post-Exercise Oxygen Consumption (EPOC) throughout the day compared to steady-state exercise. Currently, there is no single research study that examines the differences in Recovery Oxygen Consumption (ROC) resulting from high-intensity interval training (HIIT) modalities. The purpose of this study is to review the impact of circuit training (CT) and speed interval training (SIT), on ROC in both regular exercising and sedentary populations. A total of 26 participants were recruited from the UW-Eau Claire campus and divided into regularly exercising and sedentary groups, according to self-reported exercise participation status. Oxygen consumption was measured during and after two HIIT sessions and was used to estimate caloric expenditure. There was no significant difference in caloric expenditure during and after exercise among individuals who regularly exercise and individuals who are sedentary. There was also no significant difference in ROC between regular exercisers and sedentary or between SIT and CT. However, there was a significantly higher caloric expenditure in SIT vs. CT regardless of exercise status. It is recommended that individuals engage in SIT vs. CT when the goal is to maximize overall caloric expenditure. With respect to ROC, individuals can choose either modalities of HIIT to achieve similar effects on increased oxygen consumption post-exercise. KEY WORDS: Energy expenditure, exercise participation status, portable O2 analyzer INTRODUCTION Prolonged sedentary behavior and obesity resulting from physical inactivity pose threats to individual health and contribute to a cascade of chronic conditions over the lifespan. The American College of Sports Medicine (ACSM) 2015 pre-participation screening guidelines Int J Exerc Sci 10(7): 942-953, 2017 define an individual engaging in planned, structured physical activity for at least 30-min of aerobic exercise at moderate intensity on at least 3 days per week for at least the last 3 months, as a regular exerciser (16). This can be accumulated through ≥10-min bouts of exercise and contain both moderate and vigorous intensity activities (10). In today’s society, it has become a challenge to meet and/or exceed this criterion. One of the most commonly cited perceived barriers to exercise is the belief that exercise consumes too much time (7). Current findings show strong evidence in the association between physical inactivity and mortality from all causes including cardiovascular diseases (15). Therefore, Thorp and colleagues discussed the obesity and type II diabetes increase and concluded that physical activity levels, along with the detrimental effects of sedentary behavior, should be addressed (19). Previous research indicates that those with higher fat mass tend to be classified as sedentary individuals (5). According to Clapham, total daily energy expenditure (TDEE) is in relation to the total heat production in the body each day (5). Components of TDEE include resting metabolic rate (RMR), thermic effect of food (dietary component), thermogenesis from cold environments (shivering), and physical activity. RMR is the lowest rate of TDEE. It relates to the amount of fat free mass in the human body and may be used as a variable to determine obesity status. A low RMR in addition to low TDEE can contribute to weight gain. Clapham states that through the process of thermogenesis, heat drives the force in metabolism from oxygen consumption (VO2) (5). Physical activity is shown to be connected with 8-15% of TDEE and muscular activity induces thermogenesis (5). This can include walking, running, stair climbing, etc. Non-exercise activity thermogenesis (NEAT) can be displayed through subconscious physical activity such as fidgeting and upholding posture throughout the day. Those who have greater amounts of NEAT throughout the day tend have less fat gain and are less likely to over eat. These individuals who achieve NEAT and participate in regular physical activity are more likely to have an increased maximal VO2 than those who are physically inactive (5). The current research considers the direct relationship between maximal oxygen consumption (VO2max) and Recovery Oxygen Consumption (ROC). VO2max is the maximum rate of oxygen an individual consumes to supply their muscles and other organs with sufficient oxygen. According to Laforgia, Withers, and Gore, EPOC is referred to as an increased metabolism during recovery from a session of exercise (14). In an attempt to replenish the body and phosphagen system back to resting state, the oxygen rate within the body becomes elevated succeeding physical activity due to an increase in body temperature during exercise (14). Research also shows a relationship between exercise intensity and the extent of one’s EPOC for a given exercise duration (14). EPOC is increased exponentially as exercise intensity increases; as opposed to linear increase as exercise duration increases (14). In addition, according to Weston, Taylor, Batterham, and Hopkins, the same exercise intensity with high-intensity interval training (HIIT) elicits a higher VO2max than steady-state exercise in healthy, active adults (22). Since VO2max is directly correlated to intensity, a higher intensity elicits a higher EPOC (14). International Journal of Exercise Science 943 http://www.intjexersci.com Int J Exerc Sci 10(7): 942-953, 2017 Previous research examines EPOC and energy expenditure and supports HIIT as a more effective, efficient form of exercise in comparison with steady-state exercise (e.g. endurance training) (22). In regards to energy expenditure, the duration of EPOC is shown to be similar between exercise intensities (17). The importance and relevance of HIIT is addressed through recent evidence on the benefits in relation to health outcomes. However, there is little research done within various modalities of HIIT (e.g. treadmill, elliptical, stationary cycling) and more research is needed to assess the effectiveness of different modalities on ROC. The purpose of this study was to review the impact of two HIIT modalities, circuit training (CT) and speed interval training (SIT), on ROC in those who exercise regularly and those who are sedentary. The results of this study may offer alternative methods of exercise for indiv (...truncated)