How to prescribe aerobic and strength exercises to an obese person?

Aerobic and strength exercises for individuals with obesity should be prescribed as part of a tailored, multicomponent intervention that considers the person’s preferences, initial fitness, health status, and lifestyle.

The frequency of aerobic exercise is generally recommended at 3 to 5 days per week aiming for a moderate to vigorous intensity, for a total of approximately 250–300 minutes per week. Aerobic activities should include exercises using large muscle groups with repetitive movements such as walking, cycling, swimming, or running, progressing from moderate intensity (40%–60% VO2 reserve or heart rate reserve) to moderate-vigorous (50%–75% VO2 reserve) as tolerated. Duration per session typically ranges from 30 to 60 minutes, starting low and gradually increasing (NICE NG246,Komici et al. 2026,Zhang et al. 2025).

Strength (resistance) exercises should be performed 2 to 3 days per week, focusing on major muscle groups. Initial intensity is typically set at 60%–70% of one repetition maximum (1-RM), progressing to 70%–80% 1-RM over weeks. Each session usually includes 2–4 sets of 8–12 repetitions per exercise. Resistance training effectively increases lean muscle mass, reduces fat mass, and helps preserve muscle during weight loss, which is critical in obesity management. Using free weights, resistance machines, body weight, or elastic bands are appropriate modalities (NICE NG246,Komici et al. 2026,Zhang et al. 2025).

Although aerobic exercise promotes improvements in cardiorespiratory fitness and weight regulation, resistance training significantly improves body composition by increasing muscle mass and reducing adiposity. The combination of aerobic and resistance training is more effective for fat mass reduction, insulin sensitivity enhancement, and metabolic regulation than either modality alone (Zhang et al. 2025,Komici et al. 2026). For example, combined moderate-intensity aerobic exercise with resistance training and high-intensity interval training (HIIT) has been shown to optimize reductions in visceral adipose tissue with superior metabolic benefits Zhang et al. 2025.

Exercise intensity should be individualized using objective metrics such as heart rate reserve, VO2 max, or perceived exertion scales, and adjusted gradually to improve adherence and safety. Pre-exercise evaluation including assessment of cardiovascular risk, comorbidities, musculoskeletal conditions, and functional capacity is recommended to guide safe prescription (Komici et al. 2026). Importantly, exercise volume (frequency × intensity × time) should progress incrementally based on the person’s tolerance.

In people with obesity, exercising at moderate intensity (e.g., RPE 12–13) is generally sufficient to elicit benefits, with higher intensities reserved for those who can safely tolerate them. HIIT may offer additional fat loss and metabolic improvements even with shorter sessions but requires professional supervision to mitigate risks (Zhang et al., 2025; Komici et al. 2026).

Resistance training not only contributes to fat loss but is essential to prevent loss of lean muscle mass during energy-restriction based weight management programs, helping to sustain resting metabolic rate (NICE NG246,Zhang et al. 2025). Training should avoid excessive strain and Valsalva maneuvers, progressing within pain limits.

Flexibility and balance exercises are beneficial adjuncts, prescribed 2 or more days per week, to improve joint mobility and functional stability, particularly if there are musculoskeletal limitations (Komici et al. 2026).

Support and behavioural strategies to improve motivation, adherence, and reduce sedentary time are integral components of exercise prescription in obesity. Tailoring the program to individual preferences and needs increases engagement (NICE NG246,Komici et al. 2026).

For overweight or obese pregnant women, moderate-intensity aerobic activity (e.g., brisk walking, swimming) for at least 150 minutes per week is advised, with incorporation of moderate resistance training to improve muscular strength, postural stability, and mitigate gestational weight gain. Exercise programs should be individualized, supervised when possible, and account for pregnancy-related physiological changes (Li et al. 2025).