Physical exercise intensity prescription to impreve health and fitness in overweight and obese subject: A review of the literature

ABSTRACT Obesity is one of the greatest public health challenges of the 21st century. Overweight and obesity drastically increase a person’s risk of developing chronic non-communicable diseases (NCDs), including cardiovascular disease, can- cer and diabetes. Furthermore, obesity is al- ready responsible for 2% - 8% of health costs and 10% - 13% of deaths in several industrial- ized countries. Lifestyle modifications involving changes in exercise, diet and psychological support are effective in reducing the incidence of overweight. Moreover, positive effects of physical activity (PA) for weight loss and pre- vention of weight regain are well documented. It was recognized that health benefits regarding both psychological and physiological aspects, such as improving cardiorespiratory and mus- cular fitness and/or decreasing depression symptoms, can be obtained from numerous ac- tivities. Public health institutions (American College of Sports Medicine, World Health Or- ganization) provide recommendations for PA (volume, frequency, intensity and type of exer- cise) to achieve positive effects, at all ages and for many diseases and disorders situations. Al- though exercise under guidelines can be safely performed by obese subjects, several questions still need to be fully answered. In facts, the ex- ercise program should be tailored according to an individual’s habitual physical activity, physi- cal function, health status, exercise responses, and stated goals. Thus, this review analyzes the intensity of PA parameters. In the last years, re- search has been focused on the individualiza- tion of the right intensity in which different types of subjects’ condition must undergo to achieve the health goals. Aerobic exercise has been commonly used to reach weight loss goal. Pre- scription of aerobic exercise in clinical practice is frequently based on the percentage of maxi- mum heart rate (%HRmax), heart rate reserve (%HRreserve), rating of perceived exertion (RPE), maximal oxygen consumption (%VO2max) and for unhealthy subjects, peak oxygen consumption (%VO2peak). It has been shown that unhealthy subjects, such as individuals affected by diabe- tes, obesity and cardiovascular diseases have a reduced maximal aerobic exercise capacity. For instance, using the formula based on percent- age of HRmax or VO2max, it could be prescribed heavy exercises, which would result not appro- priated and fully functional for the specific indi- vidual goal. To avoid this problem, another ap- proach to individualize aerobic exercise could be to consider the gas exchange parameters such us aerobic gas exchange threshold (AerTGE). AerTGE corresponds to the first in- crease in blood lactate during incremental exer- cise. This review offers an overview of the dif- ferent methods to assess exercise intensity, considering the different subjects health char- acteristics, in order to choose the right methods to achieve the health goals in obese and over- weight subjects.