Obesity represents a significant public health concern with one-third of adults classified as living with obesity in the United States. It correlates with cardio-metabolic comorbidities that can decrease the quality of life. Researchers have proposed that exercise is an important lifestyle measure to maintain a healthy weight. This review will cover the role of exercise in obesity and fitness.
Obesity is an excessive fat accumulation in adipose tissues and is defined by a body mass index (BMI) of 30 kg/m2 and above. Individuals in the BMI range of 25 to 30 kg/m2 are categorized as overweight while a BMI of 40 kg/m2 and above is regarded as morbid obesity. Obesity correlates with an individual’s increased risk of cancers, stroke, metabolic disease, heart failure, and other cardiovascular conditions, highlighting the need to reduce the incidence and prevalence of obesity. Chronic low-grade inflammation associated with obesity is hypothesized to have associations with adverse cardio-metabolic side effects. Although short-term inflammation is beneficial to initiate an immune response, chronically elevated levels of inflammation exhaust the immune system and contribute to immune dysfunction. Researchers posit that this inflammation is stimulated by the excess adipose tissue, which has consistently shown to play a role as an active endocrine organ.
Reducing adipose tissue is one of the ways to reduce weight in individuals with obesity, and is necessary to mitigate negative cardio-metabolic co-morbidities in obesity. Two methods exist that can effectively decrease adipose tissue and include:
- Dietary modification
- Energy expenditure modification (i.e., exercise)
Thus, increasing energy expenditure can help reduce excess adipose tissue and obesity. The current guidelines put out by the American College of Sports Medicine (ACSM) include either aerobic or anaerobic exercise. Aerobic exercise (i.e., running, cycling, rowing, etc.) is an exercise that exhausts the oxygen in the muscles, but oxygen consumption is sufficient to supply the energy demands placed on the muscles and does not need to derive energy from another source. On the other hand, anaerobic exercise (or resistance exercise, i.e., weight lifting) is oxygen consumption that is not sufficient to supply the energy demands placed on the muscles, and muscles must break down other energy supplies, such as sugars, to produce energy and lactic acid. Physical activity (PA), is included in the exercise, although it does not necessarily include structured exercise plans/sessions.
The measurement of exercise is conducted in “metabolic equivalent tasks” (METs), which roughly equate to the effort and energy expenditure it takes for an individual to sit quietly. Physical activity is frequently incorporated into different lifestyle interventions, highlighting the need for regular amounts of physical activity throughout the day. Physical activity in the general lifestyle includes goal setting, problem-solving, leisure-time physical activity, and activity used for commuting. Outcomes of interest include cardiorespiratory fitness, body composition, and muscular fitness. Recently, much literature has shown the positive effects of exercise on not only physical health but also cognitive and emotional well-being in people of all ages.