Metabolic Indicators and Energy Expenditure in Two Models of Gym Classes

Abstract

Daily energy expenditure is influenced by several factors and physical activity (PA) is the most variable (Foureaux et al., 2006). However, depending on activity’s intensity, different substrates can be metabolized to consume energy. PURPOSE: This study aimed to analyse differences in metabolic indicators and energy expenditure in two different types of fitness classes: Aerobic Dance (AD) and Localized Fitness (LF). METHODS: Participants were 15 adult women aged 33,3±8,3 years with a minimum of six months experience in AD and LF. Maximum oxygen uptake (VO2max) and maximum heart rate (HRmax) were measured directly during a maximal treadmill test. During exercise sessions (AD and LF), heart rate (HR), oxygen uptake (VO2), respiratory exchange ratio (RER) metabolic equivalents (MET), percentage of fat oxidation (%FAT), percentage of carbohydrates oxidation (%CHO) and energy expenditure (EE), were assessed using a portable gas analyser (K4b2, Cosmed, Italy). Paired samples Student’s T-test was used to analyse differences between AD and LF. Significance level as set at 5%. RESULTS: Results indicated greater values during the AD session in comparison to the LF session on the following variables: VO2 (35.7±4.7 vs. 20.2±3.4 ml.kg-1.min-1; P<0.001), HR (160.9±13.2 vs. 133.9±19.4 bpm; P<0.001); MET (10.2±1.3 vs. 5.8±1.0 MET; P<0.001), EE (608.9±73.7 vs. 350.3±64.5 kcal.h-1; P<0.001), total fat oxidation (5.6±4.6 vs. 2.7±2.0 g.h-1; P<0.001) and total CHO oxidation (139.9±14.1 vs. 81.6±16.5 g.h-1; P<0.001). No differences were found for RER, %FAT and %CHO. During AD sessions, %CHO was higher than %FAT (92.3±6.2 vs. 7.9±6.4%; P<0.001). During LF sessions, %CHO was higher than %FAT (92.9±5.43 vs. 7.2±5.4%; P<0.001). CONCLUSION: These results suggest that AD induces greater metabolic demands and energy expenditure than LF. However, engaging AD or LF 3 to 5 times a week seems enough to achieve PA recommendations of 150 minutes of moderate-to-vigorous intensity activities per week (WHO, 2010), promoting several health benefits (ACSM, 2011). Although, AD and LF are equivalents on the percentage of fat and carbohydrate oxidation, carbohydrate is the main energy supply for both fitness classes.