This study will investigate whether a single dose of beetroot juice can improve cardiovascular responses and recovery after exercise in adults with Type 2 Diabetes.
Type 2 Diabetes is associated with higher blood pressure, impaired blood vessel function, and reduced autonomic control of the heart, all of which increase cardiovascular risk and may affect how the body responds to and recovers from physical activity. Beetroot juice is naturally rich in dietary nitrate, which is converted in the body into nitric oxide, a molecule that helps blood vessels relax and improve blood flow. While these effects have been demonstrated in healthy individuals, less is known about their impact in people with Type 2 Diabetes.
In this study, approximately 16 to 20 adults aged 40 to 65 years with Type 2 Diabetes will take part. After an online screening and consent process, eligible participants will attend two laboratory visits at Oxford Brookes University. In a randomised, double-blind, placebo-controlled crossover design, participants will receive beetroot juice during one visit and a nitrate-depleted placebo during the other visit.
During each visit, participants will undergo physiological measurements, including blood pressure, heart rate, oxygen saturation, and capillary blood glucose. Participants will then complete a short session of supervised, light-to-moderate cycling exercise. Measurements will continue during the recovery period to assess how quickly the cardiovascular system returns to resting levels.
The main outcomes are systolic blood pressure and heart rate variability during recovery, which reflect cardiovascular regulation and autonomic function. Secondary outcomes include diastolic blood pressure, heart rate, blood glucose, and markers related to nitric oxide availability.
This study may help determine whether a simple, dietary-based intervention such as beetroot juice can support cardiovascular function and improve recovery after exercise in people living with Type 2 Diabetes.
Clinically diagnosed Type 2 Diabetes Mellitus
Aged 40 to 65 years
Not treated with insulin
Stable diabetes medication regimen for at least 3 months
Current or recent use of insulin
Use of organic nitrates (e.g., glyceryl trinitrate) or phosphodiesterase-5 inhibitors (e.g., sildenafil, tadalafil)
Use of systemic antibiotics within the specified preparation period or regular use of antiseptic/antibacterial mouthwash during study participation
Use of supplements known to interfere with nitric oxide metabolism within the defined preparation period