Acute consumption of dietary nitrate (as beetroot juice) has been shown to decrease systemic blood pressure in multiple populations as well as increase organ perfusion in areas of interest such as the pancreas and brain. Obstructive sleep apnoea syndrome (OSAS) is associated with high blood pressure, dysglycaemia and impaired vigilance. The effect of dietary nitrate in OSAS has not been reported.

Acute consumption of dietary nitrate (as beetroot juice) has been shown to decrease systemic blood pressure in multiple populations as well as increase organ perfusion in areas of interest such as the pancreas and brain. Obstructive sleep apnoea syndrome (OSAS) is associated with high blood pressure, dysglycaemia and impaired vigilance. The effect of dietary nitrate in OSAS has not been reported.

The investigators hypothesize that chronic nitrate consumption might decrease blood pressure and dysglycaemia and improve vigilance compared to a placebo beetroot juice.

This study is a randomized, double-blind placebo-controlled, crossover trial. At baseline, mid-point and endpoint ambulatory blood pressure will be assessed in conjunction with demographics, questionnaires, vigilance and blood draw. After baseline measures, each subject will be randomized to consume nitrate rich beetroot juice for 14 consecutive nights when assessments will be repeated followed by 14 nights of placebo and endpoint assessments or the converse.

Inclusion Criteria:

• Clinically stable,
• Untreated OSAS out-patients

Exclusion Criteria:

• Using continuous positive airways pressure therapy
• Pulmonary hypertension
• Active CVD
• Active musculo-skeletal conditions
• Taking vasodilators
• Diabetes mellitus