[Evaluation of the deficiency and the submaximal exercise capacity in obstructive sleep apnoea patients].

BACKGROUND

In addition to excessive daytime somnolence, exercise limitation is a likely consequence of the cardiorespiratory problems that occur in patients who have obstructive sleep apnoea (OSA). However, few studies have evaluated the aerobic capacity of this patient group.

AIMS: To evaluate submaximal exercise capacity over the 6-minute walking test (6-MWT). To determine the factors that influence 6-minutes walking distance (6-MWD).

INCLUSION CRITERIA: 120 consecutive patients with severe OSA treated by continuous positive airway pressure who were medically stable will be included.

EXCLUSION CRITERIA: 6-MWT contraindications, orthopaedic or rheumatologic diseases likely to influence walking capacity and corticosteroid therapy.

INVESTIGATIONS: polysomnography, electrocardiogram, plethysmography, and two 6-MWT's. Indicators of impaired exercise capacity: stops during the walk, 6-MWD less than or equal to predicted lower limit of normal, end walking dyspnoea greater than or equal to 5/10, oxygen saturation fall greater than or equal to five points, end walking heart rate less than or equal to 60 % maximal predicted. Data from our obese patients aged 40-60 years old will be compared with data from 45 age-matched obese subjects free from OSA.

EXPECTED

RESULTS

OSA will significantly affect the submaximal exercise capacity and will accelerate the ageing of the cardiorespiratory-muscle chain. Submaximal exercise capacity of obese subjects having OSA, compared to subjects free from OSA, will be significantly deteriorated. 6-MWD of OSA patients will be significantly influenced by: resting plethysmographic data, apnoea hypopnoea index, arterial hypertension, obesity or smoking histories.