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

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, cancer and diabetes. Furthermore, obesity is already responsible for 2% -8% of health costs and 10% -13% of deaths in several industrialized 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 prevention of weight regain are well documented. It was recognized that health benefits regarding both psychological and physiological aspects, such as improving cardiorespiratory and muscular fitness and/or decreasing depression symptoms, can be obtained from numerous activities. Public health institutions (American College of Sports Medicine, World Health Organization) provide recommendations for PA (volume, frequency, intensity and type of exercise) to achieve positive effects, at all ages and for many diseases and disorders situations. Although exercise under guidelines can be safely performed by obese subjects, several questions still need to be fully answered. In facts, the exercise program should be tailored according to an individual’s habitual physical activity, physical function, health status, exercise responses, and stated goals. Thus, this review analyzes the intensity of PA parameters. In the last years, research has been focused on the individualization 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. Prescription of aerobic exercise in clinical practice is frequently based on the percentage of maximum 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 diabetes, obesity and cardiovascular diseases have a reduced maximal aerobic exercise capacity. For instance, using the formula based on percentage of HRmax or VO2max, it could be prescribed heavy exercises, which would result not appropriated and fully functional for the specific individual goal. To avoid this problem, another approach to individualize aerobic exercise could be to consider the gas exchange parameters such us aerobic gas exchange threshold (AerTGE). AerTGE corresponds to the first increase in blood lactate during incremental exercise. This review offers an overview of the different methods to assess exercise intensity, considering the different subjects health characteristics, in order to choose the right methods to achieve the health goals in obese and overweight subjects.

Negative association between trunk fat, insulin resistance and skeleton in obese women

AIM: To evaluate the potential interference of trunk fat (TF) mass on metabolic and skeletal metabolism. METHODS: In this cross-sectional study, 340 obese women (mean age: 44.8 ± 14 years; body mass index: 36.0 ± 5.9 kg/m 2 ) were included. Patients were evaluated for serum vitamin D, osteocalcin (OSCA), inflammatory markers, lipids, glucose and insulin (homeostasis model assessment of insulin resistance, HOMA-IR) levels, and hormones profile. Moreover, all patients underwent measurements of bone mineral density (BMD;at lumbar and hip site) and body composition (lean mass, total and trunk fat mass) by dual-energy X-ray absorptiometry. RESULTS: Data showed that: (1) high TF mass was inversely correlated with low BMD both at lumbar (P < 0.001) and hip (P < 0.01) sites and with serum vitamin D (P < 0.0005), OSCA (P < 0.0001) and insulin-like growth factor-1 (IGF-1; P < 0.0001) levels; (2) a positive correlation was found between TF and HOMA-IR (P < 0.01), fibrinogen (P < 0.0001) and erythrocyte sedimentation rate (P < 0.0001); (3) vitamin D levels were directly correlated with IGF-1 (P < 0.0005), lumbar (P < 0.006) and hip (P < 0.01) BMD; and (4) inversely with HOMA-IR (P < 0.001) and fibrinogen (P < 0.0005). Multivariate analysis demonstrated that only vitamin D was independent of TF variable. CONCLUSION: In obese women, TF negatively correlates with BMD independently from vitamin D levels. Reduced IGF-1 and increased inflammatory markers might be some important determinants that account for this relationship.

Sarcopenic Obesity: Correlation with Clinical, Functional, and Psychological Status in a Rehabilitation Setting

Obesity and sarcopenia combination, appropriately defined as sarcopenic obesity (SO), due to disproportionally reduced/low lean body mass compared to excess fat mass, may lead to disability. Aims: The aim of our study was to investigate the relationship among sarcopenic obesity, physical performance, disability, and quality of life in a rehabilitation setting. Methods: Participants were recruited among obese patients (BMI > 30 kg/m2) admitted to the rehabilitation facility at the Department of Experimental Medicine, Medical Physiopatology, Food Science and Endocrinology Section during a 1-year period. A multidimensional evaluation was performed through bioelectrical impedance analysis and anthropometry, handgrip strength test, Short Physical Performance Battery (SPPB), 6-minute walk test (6MWT) and blood chemistry parameters. Psychological status (SCL-90 questionnaire), quality of life, and comorbidity (Charlson comorbidity index score) were also evaluated. Obesity was diagnosed as increased fat mass by 35% in women and by 25% in men. Sarcopenia was defined if lean body mass (LBM) was <90% of the subject’s ideal LBM. Results: 79 patients (48 women and 31 men;mean age: 60.1 ± 11.5 years, and 58.6 ± 10.8 years, respectively) were enrolled. Results showed a high prevalence of SO (54.4%) in our samples of obese subjects. Sarcopenia was present not only among older obese adults but also among younger obese subjects, and was related to reduced functional performance, to inflammatory status and to worse psychological status and quality of life.