Cerebral Blood Flow and Ventilatory Responses During Sleep in Normoxia and Intermittent Hypoxia

Role of Cerebral Blood Flow on Ventilatory Stability During Sleep in Normoxia and Intermittent Hypoxia

A prospective double blind, placebo-controlled, randomized cross-over trial to evaluate the effect of lowering cerebral blood flow on the ventilatory chemoreflexes (acute hypoxic and hypercapnic ventilatory responses).

The investigators will explore the relationship between changes in Cerebral Blood Flow (CBF) and ventilatory chemoreflexes i.e. Acute Ventilatory Response to Hypoxia (AHVR) and Acute Hypercapnic Ventilatory Response (HCVR) before, during and after sleep under normoxic conditions and sleep accompanied by isocapnic Intermittent Hypoxia (IH) among healthy human study participants.

A pharmacological intervention will be utilized to manipulate the CBF in a randomized order. The study participants will also be randomly assigned the order to sleep either under normoxia or IH exposure. The experiments will be separated from one another with an interval of sufficient drug and IH exposure washout period. The venous blood samples and urinary samples will be collected for the vascular biomarkers.

Inclusion Criteria:

• Healthy adults
• 18 - 45 years of age
• Living in Calgary for the past one year
• Have no medical condition or should not be taking any blood pressure medications.
• The participant should not be lactose intolerant

Exclusion Criteria:

• Cerebrovascular, cardio-respiratory, renal and metabolic diseases
• Bleeding disorders and upper gastrointestinal diseases e.g. peptic ulcer disease
• Pregnancy, obese and sleep-disordered breathing
• Drug allergies to non-steroidal anti-inflammatories
• Currently smoking