This study aimed to compare the effect of constant-load aerobic exercise (CL-AE) and graded aerobic exercise (G-AE) on cardiopulmonary fitness, and functional capacity in a cohort of obese children with bronchial asthma (BA).

A total of 78 children with BA were randomly assigned to the CL-AE group (n = 26, who underwent moderate-intensity aerobic training with the training load maintained at the same level throughout the entire program, besides the respiratory re-training program), the G-AE group (n = 26, received an intensity- and duration-graded aerobic training in addition to the respiratory re-training program), or the control group (n = 29, who only engaged in a respiratory re-training program). Interventions were administered three times/week for 12 successive weeks.

The cardiopulmonary fitness and functional capacity were evaluated in the three groups before and after the completion of the assigned interventions.

Seventy-eight children with BA were recruited from the Pulmonary Medicine/Critical Care and Allergy-Immunology at King Khalid Hospital and two referral hospitals in Riyadh, Saudi Arabia. The study included children with moderate, clinically stable BA, aged 8-18 years, had a body mass index between 30 to 35 kg/m2, had no abnormalities of the lower limbs or spine, maintained constant medication dosages in the past three months, and did not engage in a regular exercise program (in the past six months). Children were excluded if they had exacerbated asthma symptoms, chronic lung comorbidities, and cardiovascular or musculoskeletal conditions expected to hinder the training.

Outcome measures

Cardiopulmonary fitness: The peak oxygen uptake was assessed through the McMaster cycling protocol.

Functional Capacity: The 6-minute walk test was used to assess the submaximal functional capacity Perceived dyspnea and fatigue: Borg's category ratio scale (CR-10) was used to explore how much dyspnea and fatigue they perceived after the 6-minute walk test.

Interventions

The CL-AE group received a 12-week aerobic training, three times in addition to the respiratory re-training. the program included a moderate-intensity aerobic training program, with an intensity set at 65% of the maximum age-predicted heart rate for 45 minutes. The training intensity and duration were maintained at the same level throughout the program. The CL-AE program included a warm-up for 5 minutes and a cool-down for 5 minutes.

The G-AE group received a 12-week aerobic training, three times in addition to the respiratory re-training. The G-AE program commenced with a training intensity corresponding to 50% of the maximum age-predicted heart rate for 25 minutes in the first two weeks, which progressed on a two-week basis, and ended up with a training intensity corresponding to 75% of the maximum age-predicted heart rate for 50 minutes in the last two weeks. The G-AE program also included a warm-up for 5 minutes and a cool-down for 5 minutes.

The control group received the respiratory re-training only, 30 minutes per session, three times a week for 12 consecutive weeks. The program consisted of diaphragmatic breathing exercises, breath-hold, and breathing control exercises, pursed lip breathing, respiratory muscle strengthening, postural correction exercises, and relaxation techniques.

Inclusion Criteria:

• Age of 8-18 years
• Body mass index ranging from 30 to 35 kg/m2
• Verified asthma diagnosis per the Global Initiative for Asthma (GINA) criteria
• Moderate Onset
• Clinically Stable
• Maintained medication dosages in the past three months
• Free of lower limb or spinal deformities
• Not engaging in regular exercise regimens in the past six months.

Exclusion Criteria:

• Exacerbated asthma symptoms
• Chronic lung comorbidities
• Cardiovascular or musculoskeletal conditions expected to hinder the training.

A single-blind protocol was adopted. The researcher who collected the data was blind to the allocation of treatment