The purpose of this study is to evaluate the duration of oxygen use recorded by the NOWOX, under usual conditions of daily living, in patients with chronic obstructive respiratory disease requiring oxygen therapy.

Long Term Oxygen Therapy (LTOT) is one of the main non pharmacologic treatments for patients with severe lung disease. This continuous or sub-continuous oxygen supplementation is generally introduced at home in patients who have chronic cardio respiratory failure and severe resting hypoxemia to maintain sufficient blood oxygenation and therefore preserve vital organ function.

LTOT effectiveness has mainly been evaluated and documented in patients with COPD, which also accounts for most of its prescriptions. In these patients, LTOT has been shown to have a beneficial impact on haemodynamics, exercise capacity, lung mechanics and mental state. Its implementation was furthermore associated with reduced yearly hospitalisation days and increased survival Measuring adherence is an extremely important and under-evaluated component of oxygen therapy. NOWOX, medical device has been designed,developed and manufactured to measure adherence to LTOT and additionally to measure patient's respiration rate

Inclusion Criteria:

• Male or female patient aged ≥ 18 years and ≤ 75 years,
• Having a documented diagnosis of moderately severe to severe chronic obstructive respiratory disease
• Hospitalised or out-patient requiring transient or long term oxygen therapy,
• Able to be weaned from oxygen for several consecutive minutes (around 30 minutes, SpO2 at rest on room air should not drop < 85%),
• Able to read
• Willing and able to complete the requirements of this study including providing his/her signature for the written informed consent.

Exclusion Criteria:

• Clinically unstable patient,
• Any contraindication to perform a light cycling exercise, according to the 2003 ATS/ACCP guidelines
• Tracheostomy,
• Nasal obstruction or acute rhinitis occurring in the week prior to selection,
• For female patient:
• Pregnant,
• Positive urinary pregnancy test
• Lactating mother or lack of efficient contraception
• Clinically significant or uncontrolled cardiac, hepatic, renal, gastrointestinal, endocrine, metabolic, autoimmune, neurological or psychiatric disorders which may interfere with the study procedures,
• Known allergic reactions to medical material compounds used in the study
• Drug abuse or psychic disorders
• Legal status which prohibits informed consent,
• Participation in any interventional clinical trial within 30 days prior to selection.