Influence of neck circumference on respiratory endurance and muscle strength in the morbidly obese.

BACKGROUND

Respiratory function decline has been reported mainly in the morbidly obese. Little is known about the influence of adiposity pattern on the ability to generate strength in respiratory muscles. This study evaluated strength and respiratory endurance in the morbidly obese in preoperative bariatric surgery to determine if such variables were affected by different anthropometric markers (body mass index (BMI), waist-hip ratio (WHR), and neck circumference (NC)).

METHODS

We evaluated 39 adult and young obese patients of both sexes, with no respiratory or heart diseases. Standard pulmonary function tests and static respiratory muscle strength (maximum inspiratory pressure (MIP) and maximum expiratory pressure (MEP)) and endurance (maximum voluntary ventilation (MVV)) were measured in relation to sex and groups (WHR > 0.95 and WHR < 0.95; NC > 43 and NC < 43).

RESULTS

Thirty-nine obese patients (28 women), aged 36.9 + 11.9 years, BMI 49.3 + 5.1 kg/m², WHR 0.96 + 0.07, and NC 44.1 + 4.2 cm, took part in the study Standard pulmonary function tests and respiratory muscle strength were within normal parameters, except MVV (<80%). Obese with NC ≥ 43 cm (n = 22) have greater respiratory muscle strength and less endurance, MEP (p = 0.031) and MVV (p = 0.018). Abdominal adiposity (n = 19) does not seem to affect respiratory muscle strength. A positive correlation was observed only between NC and PEF (r = 0.392, p = 0.014) and marginally between NC and MVV (r = 0.308, p = 0.056).

CONCLUSION

Although adiposity patterns did not affect inspiratory muscle strength, neck adiposity was associated lower respiratory muscle endurance.