According to a recent expert consensus1, obesity is defined as a disease characterized by a body mass index greater than 30 kg/m², associated with excess fat mass responsible for clinical complications that deteriorate the patient’s health. From a pathophysiological point of view, this excess fat mass causes low-grade systemic inflammation through the production of pro-inflammatory cytokines by adipose tissue (i.e., adipokines). When combined with a diet rich in simple sugars and saturated fats and/or a sedentary lifestyle and physical inactivity, systemic inflammation leads to metabolic (e.g., type II diabetes) and cardiovascular complications (e.g., hypertension, myocardial infarction)2.
Moreover, excess body fat and body mass increase mechanical stress on the musculoskeletal system (muscles, bones, tendons, etc.), leading to numerous locomotor disorders (e.g., osteoarthritis). It also results in increased bone mass and skeletal muscle mass, as mechanical stress is the main driver of protein synthesis in muscles and bone mineralization3,4, explaining why individuals with obesity often exhibit elevated muscle and bone mass.
Currently, therapeutic management of obesity revolves around two main axes:
- Pharmacological management of associated clinical complications
- Lifestyle modifications through psychology, nutrition, and physical activity interventions. The goals are twofold: to limit or treat comorbidities linked to obesity (such as type II diabetes and cardiovascular diseases) and to establish a healthy physiological and psychological environment promoting sustainable healthy habits. Nutritional changes and physical activity help:
- Improve body composition by reducing fat mass, especially visceral fat linked to comorbidities5.
- Regulate cellular and systemic metabolism by enhancing hormonal and mitochondrial functions6,7.
- Reduce systemic inflammation, given its major role in obesity-related comorbidities8.
The World Health Organization recommends 150 minutes of moderate or 75 minutes of vigorous physical activity weekly, or a combination of both. In certain situations, selecting a specific exercise modality is crucial to achieve targeted beneficial adaptations.
During physical activity, the body undergoes temporary stress that triggers an adaptive response. Repeating this stress leads to beneficial adaptations. Therefore, it is important to understand which structures are stressed depending on the type and intensity of exercise.
Exercises are generally divided into two categories: endurance exercises and resistance exercises.
I. Aerobic Exercise
These are long-duration, moderate-intensity activities that heavily involve muscular energy systems and the cardiovascular system. They are usually performed at 55–75% of maximum heart rate, promoting aerobic energy production via mitochondria.
Aerobic exercise improves mitochondrial density and function (9), cardiovascular health (10), and glucose regulation (11), making it ideal for fat loss and physiological health improvement.
Activities include walking, running, cycling, and swimming, performed below the first ventilatory threshold. Intensity can be monitored using a heart rate monitor or by applying the “talk test”—being able to converse while occasionally pausing for breath.
II. Resistance Exercise
Resistance exercises involve strength training with external loads or body weight. They benefit the musculoskeletal and nervous systems. Moving a load increases muscle tension, stimulating protein synthesis and hypertrophy. An adequate protein intake (>1.6 g/kg/day) is recommended (12).
These exercises also enhance proprioception, balance, and mobility. They are particularly important in sarcopenic obesity or functional limitations.
Typical training protocols:
- For strength gains: 3–5 sets of 4–5 reps at 80–90% max, with 1:30–2 min rests.
- For hypertrophy: 3–5 sets of 10–12 reps at 70–80% max, with 1–1:30 min rests.
III. Importance of Bioelectrical Impedance in Obesity Management
Bioelectrical impedance, which measures body composition, is a useful tool for monitoring progress during obesity treatment. It assesses skeletal muscle mass and fat mass, helping to tailor exercise programs and set clear goals for patient involvement.
If muscle mass is sufficient and no limitations are expressed, aerobic exercise should be prioritized to promote fat loss. Otherwise, starting with resistance exercises to build muscle mass before transitioning to aerobic activities is recommended. In all cases, adapting the activity to the patient’s needs and preferences is essential to ensure long-term adherence.
Références
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13. Twomey R, Aboodarda SJ, Kruger R, Culos-Reed SN, Temesi J, Millet GY. Neuromuscular fatigue during exercise: Methodological considerations, etiology and potential role in chronic fatigue. Neurophysiol Clin Clin Neurophysiol. 2017 Apr;47(2):95–110.
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