Obesity is an escalating problem in the UK and a proportion of these patients have a condition known as Obesity Hypoventilation Syndrome (OHS). This syndrome is associated with symptoms of breathlessness, reduction in exercise capacity, fatigue and headaches. Previous research has shown that patients with this condition tend to use healthcare services more frequently and are often at risk of other diseases such as diabetes mellitus and high blood pressure. Currently, the mainstay of treatment is noninvasive ventilation (NIV), this is a mask ventilator that patients use overnight to improve oxygen levels and remove carbon dioxide (the waste gas of breathing), however this does not fully treat the underlying problem. The research group has shown that NIV helps improve activity and contributes to weight loss in this group of patients. The aim of this research will be to investigate the effect of an exercise and nutrition programme in addition to NIV on weight loss and activity levels compared to NIV alone.

Inclusion Criteria:

• Diagnosis of OHS
• Age >18
• BMI > 30 kg/m2
• Chronic hypercapnia , daytime PaCO2 >6kPa
• FEV1/FVC ≥70%
• Evidence of sleep disordered breathing on overnight studies
• Tolerated NIV > 4hrs on 1st night during initiation of NIV

Exclusion Criteria:

• Hypercapnic respiratory failure secondary to an identifiable cause other than OHS.
• Age <18
• Respiratory acidosis (pH <7.35)
• Wheelchair/bedbound patients
• Cognitive impairment which would prevent the subject from complying with trial protocol
• Unstable coronary artery syndrome
• Patients postintubation or decannulation following treatment requiring acute hypercapnic respiratory failure
• Patients undergoing renal replacement therapy
• Critical peripheral vascular disease
• Disabling locomotor disability preventing participation in exercises involved in the rehabilitation programme
• Pregnancy
• Bariatric surgery planned within 3 months