Assessing the Symptoms of Obstructive Sleep Apnea (OSA)

• Residual volume [ Time Frame: Within four weeks of recruitment prior to CPAP treatment ] [ Designated as safety issue: No ]
  Volume of air remaining in lungs after full expiration
• Functional residual volume [ Time Frame: Within four weeks of recruitment prior to CPAP treatment ] [ Designated as safety issue: No ]
  Air present in lungs at the end of passive expiration
• Total lung capacity [ Time Frame: Within four weeks of recruitment prior to CPAP treatment ] [ Designated as safety issue: No ]
  Total volume of lungs
• Forced Vital capacity [ Time Frame: Within four weeks of recruitment prior to CPAP treatment ] [ Designated as safety issue: No ]
  Maximum amount of air which can be expired from the lungs following a full inspiration
• Forced expiratory volume in one second (FEV1) [ Time Frame: Within four weeks of recruitment prior to CPAP treatment ] [ Designated as safety issue: No ]
  Maximum amount of air which can be expired from the lungs in one second.
• Airway Resistance [ Time Frame: Within four weeks of recruitment prior to CPAP treatment ] [ Designated as safety issue: No ]
  Opposition of flow caused by forces of friction.
• Plasma 2-arachidonoylglycerol (2-AG) [ Time Frame: Within four weeks of recruitment prior to CPAP treatment and after four weeks of CPAP treatment. ] [ Designated as safety issue: No ]
  Ligand of the G-protein coupled CB1 and CB2 receptors, has been found to be correlated with Oleylethanolamide (OEA) in OSA patients have various effects on energy metabolism.
• Plasma Anandamide (ANA) [ Time Frame: Within four weeks of recruitment prior to CPAP treatment and after four weeks of CPAP treatment ] [ Designated as safety issue: No ]
  Ligand of the G-protein coupled CB1 and CB2 receptors, found to be correlated with blood pressure in OSA after the adjustment of confounding variables. Have various effects on energy metabolism.
• Plasma oleoylethanolamine (OEA) [ Time Frame: Within four weeks of recruitment prior to CPAP treatment and after four weeks of CPAP treatment ] [ Designated as safety issue: No ]
  A lipid mediator which acts as an anorexigenic (appetite suppressant), and is elevated with sleep deprivation.
• Plasma Leptin [ Time Frame: Within four weeks of recruitment prior to CPAP treatment and after four weeks of CPAP treatment ] [ Designated as safety issue: No ]
  Circulating protein produced in adipose tissue. Elevated in OSA and obesity. Leptin may reduce respiratory depression.
• Plasma Adiponectin [ Time Frame: Within four weeks of recruitment prior to CPAP treatment and after four weeks of CPAP treatment ] [ Designated as safety issue: No ]
  Hormone secreted by adipocytes (Fat cells). Adiponectin is closely linked to metabolism and may have anti-inflammatory properties.
• Plasma C-reactive Protein [ Time Frame: Within four weeks of recruitment prior to CPAP treatment and after four weeks of CPAP treatment ] [ Designated as safety issue: No ]
  Marker of inflammation.
• Insulin [ Time Frame: Within four weeks of recruitment prior to CPAP treatment and after four weeks of CPAP treatment ] [ Designated as safety issue: No ]
  Hormone which causes liver and muscle and fat cells to take up glucose to convert to glycogen. OSA is associated with insulin resistance.
• Neck circumference [ Time Frame: Within four weeks of recruitment prior to CPAP treatment ] [ Designated as safety issue: No ]
• Waist circumference [ Time Frame: Within four weeks of recruitment prior to CPAP treatment ] [ Designated as safety issue: No ]
• Hip circumference [ Time Frame: Within four weeks of recruitment prior to CPAP treatment ] [ Designated as safety issue: No ]
• Weight [ Time Frame: Within four weeks of recruitment prior to CPAP treatment ] [ Designated as safety issue: No ]
• Fat-free mass [ Time Frame: Within four weeks of recruitment prior to CPAP treatment ] [ Designated as safety issue: No ]
  Non-fat components of the human body estimated non-invasively using a bioimpedance measurement system.
• Fat mass [ Time Frame: Within four weeks of recruitment prior to CPAP treatment ] [ Designated as safety issue: No ]
  Fat components of the human body estimated non-invasively using bioimpedance measurement system.
• Maximal Inspiratory pressure [ Time Frame: Within four weeks of recruitment prior to CPAP treatment ] [ Designated as safety issue: No ]
  Measured at residual volume, reflects the strength of the diaphragm and other inspiratory muscles.
• Rate of inspiratory muscle fatigue [ Time Frame: Within four weeks of recruitment prior to CPAP treatment ] [ Designated as safety issue: No ]
  The decline in maximal inspiratory pressure following inspiration against a resistance.
• Chest RPE [ Time Frame: Within four weeks of recruitment prior to CPAP treatment ] [ Designated as safety issue: No ]
  Rating of perceived exertion in the chest and associated airways during the inspiratory fatigue protocol.
• Dyspnea [ Time Frame: Within four weeks of recruitment prior to CPAP treatment ] [ Designated as safety issue: No ]
  Rating of breathlessness half way through fatigue protocol and at the end of protocol.
• Ventilation with 25% O2/ 6% CO2 [ Time Frame: Within four weeks of recruitment prior to CPAP treatment ] [ Designated as safety issue: No ]
  Measures the breathing response to high oxygen and high CO2 therefore assessing the central chemoreceptors response only.
• Ventilation with 13% O2 [ Time Frame: Within four weeks of recruitment prior to CPAP treatment ] [ Designated as safety issue: No ]
  Measures the breathing response to low oxygen. Designed to Assess the response to the peripheral chemoreceptors.
• Ventilation with 13% O2 / 6% CO2 [ Time Frame: Within four weeks of recruitment prior to CPAP treatment ] [ Designated as safety issue: No ]
  Measures the breathing response to low oxygen and high CO2. Designed to assess the response of the sum of the peripheral and central chemoreceptors
• Mean RR interval [ Time Frame: Within four weeks of recruitment prior to CPAP treatment ] [ Designated as safety issue: No ]
  Time domain measure: Average time interval between the heart beats R waves
• SDNN [ Time Frame: Within four weeks of recruitment prior to CPAP treatment ] [ Designated as safety issue: No ]
  Time domain measure: The standard deviation of all RR intervals
• NN50 count [ Time Frame: Within four weeks of recruitment prior to CPAP treatment ] [ Designated as safety issue: No ]
  Time domain measure: The number of pairs of adjacent RR intervals differing by more than 50 ms in the entire analysis interval.
• NN50 of total HR (%) [ Time Frame: Within four weeks of recruitment prior to CPAP treatment ] [ Designated as safety issue: No ]
  Time domain measure: NN50 count divided by total number of all RR intervals.
• HRV triangular index [ Time Frame: Within four weeks of recruitment prior to CPAP treatment ] [ Designated as safety issue: No ]
  The total number of RR intervals divided by maximum height of the histogram excluding boundaries.
• Low frequency domain [ Time Frame: Within four weeks of recruitment prior to CPAP treatment. ] [ Designated as safety issue: No ]
  Frequency domain analysis: represents 0.04-0.15 Hz reflecting sympathetic activity.
• High frequency domain [ Time Frame: Within four weeks of recruitment prior to CPAP treatment. ] [ Designated as safety issue: No ]
  Frequency domain analysis: represents 0.15-0.40 Hz reflecting parasympathetic activity.
• LF/HF ratio [ Time Frame: Within four weeks of recruitment prior to CPAP treatment. ] [ Designated as safety issue: No ]
  The ratio of low frequency (0.04 - 0.15 Hz) to high (0.15-0.40 Hz) frequency recordings.

The purpose of this study is to investigate the correlation between health outcomes associated with the severity of obstructive sleep apnea (OSA) symptomatology, the findings will guide the design of interventional studies.

Obstructive sleep apnea is a condition characterised by periods of narrowing of the pharyngeal airways during sleep causing hypoxic and hypercapnic episodes with the cessation of ventilation. Considering the high number of overweight and obese individuals in Western society the understanding of the pathomechanisms behind OSA are important. This observational study aims to investigate the correlations between the severity of Obstructive Sleep Apnea assessed by the apnea-hypopnea index (AHI) and different health outcomes associated with the OSA.

Mild to severe recently diagnosed Obstructive Sleep Apnea patients selected by physician who have not received any treatment for their condition. Selected from Ysbyty Gwynedd in North Wales.

Inclusion Criteria:

• Body Mass Index ≤39
• Not received any treatment for Obstructive Sleep Apnea.
• Is a non-smoker
• Is not epileptic
• Epworth Sleepiness Scale ≥ 10.
• Patient's on Statins or antihypertensive drugs are included as so frequent in OSA.

Exclusion Criteria:

• Body Mass Index ≥ 39.
• Presence of significant or unstable Renal, Liver or Heart Failure.
• Receiving anti-diabetic treatment.
• Is a smoker.
• Is epileptic
• Presence of significant or unstable psychological morbidities.