Effect of Exercise Training on Fat Loss—Energetic Perspectives and the Role of Improved Adipose Tissue Function and Body Fat Distribution

Abstract

In obesity, excessive abdominal fat, especially the accumulation of visceral adipose tissue (VAT), increases the risk of metabolic disorders, such as type 2 diabetes mellitus (T2DM), cardiovascular disease, and non-alcoholic fatty liver disease. Excessive abdominal fat is associated with adipose tissue dysfunction, leading to systemic low-grade inflammation, fat overflow, ectopic lipid deposition, and reduced insulin sensitivity. Physical activity is recommended for primary prevention and treatment of obesity, T2DM, and related disorders. Achieving a stable reduction in body weight with exercise training alone has not shown promising effects on a population level. Because fat has a high energy content, a large amount of exercise training is required to achieve weight loss. However, even when there is no weight loss, exercise training is an effective method of improving body composition (increased muscle mass and reduced fat) as well as increasing insulin sensitivity and cardiorespiratory fitness. Compared with traditional low-to-moderate-intensity continuous endurance training, high-intensity interval training (HIIT) and sprint interval training (SIT) are more time-efficient as exercise regimens and produce comparable results in reducing total fat mass, as well as improving cardiorespiratory fitness and insulin sensitivity. During high-intensity exercise, carbohydrates are the main source of energy, whereas, with low-intensity exercise, fat becomes the predominant energy source. These observations imply that HIIT and SIT can reduce fat mass during bouts of exercise despite being associated with lower levels of fat oxidation. In this review, we explore the effects of different types of exercise training on energy expenditure and substrate oxidation during physical activity, and discuss the potential effects of exercise training on adipose tissue function and body fat distribution.

“HIIT the Inflammation”: Comparative Effects of Low-Volume Interval Training and Resistance Exercises on Inflammatory Indices in Obese Metabolic Syndrome Patients Undergoing Caloric Restriction

“…Accordingly, it has been reported that energy expenditures during low-volume exercise modalities, including LOW-HIIT [ 71 ], 1-RT [ 72 ] and WB-EMS [ 73 ], are quite small, ranging around 120–150 kcal per exercise session. However, it has also been documented that HIIT exercises are particularly effective to stimulate excess post-exercise oxygen consumption (EPOC), a valid measure to quantify elevated energy expenditure after cessation of exercise, which has been associated with higher fat loss over a longer period of time [ 74 , 75 , 76 ]. Furthermore, it has recently been shown that both HIIT and traditional RT resulted in increased resting metabolic rate for at least 14 h post-exercise in healthy women [ 77 ].…”

Astaxanthin Supplemented with High-Intensity Functional Training Decreases Adipokines Levels and Cardiovascular Risk Factors in Men with Obesity

“…Reducing energy consumption, increasing energy expenditure, and increasing muscle mass hold promise in the management of obesity and associated complications [ 19 , 20 ]. However, the effects of regular exercise training to manage obesity and related diseases are related to the modes of exercise [ 21 ]. For example, CrossFit training (a high-intensity mixed exercise model of concurrent strength and endurance performance) reduces lipid oxidation in obese individuals [ 22 , 23 ].…”

Assessment of Subjective Well-Being in a Cohort of University Students and Staff Members: Association with Physical Activity and Outdoor Leisure Time during the COVID-19 Pandemic

“…While physical activity (PA) has long been associated with a reduced risk of mortality and morbidity from chronic and degenerative diseases [16][17][18][19][20][21], the research interest on the role of PA on mental health has emerged more recently. PA has been related to an improvement in general well-being [22], enhanced perception of quality of life [23,24] and mood, as well as to a significant reduction in anxious and depressive symptomatology [25].…”