Comparison of NZ beetroot juice with UK beetroot juice supplementation on exercise performance, cognition, and cardiovascular function in recreationally trained exercisers

INTERVENTION:

The UKvNZ is a randomized controlled crossover trial designed to compare the benefits of juice from beetroot grown in NZ and UK following 7 days’ supplementation on exercise, cognitive performance, and cardiovascular function. Participants will come to the lab for four trials namely, familiarization trial, placebo, UK beetroot juice, and NZ beetroot juice trial. During the familiarization trial participants will provide blood sample using venipuncture (baseline plasma nitrite/nitrate) and complete the maximal oxygen uptake (VO2max) test. After a 15min rest, they will complete a familiarization of the 4‐km cycling time trial. Participants will undertake 6 days’ supplementation after the familiarization trial (with one of the three drinks: placebo, UK beetroot juice drink or NZ beetroot juice drink) for each trial; on the 7th day, will be asked to come into the lab fasted. Participants will provide a finger prick blood sample and will consume breakfast and then undergo baseline tests. Participants will then consume assigned supplement and will wait for 2.5 h before completing the 120‐minute cycling exercise at 70% of VO2max. This will be followed by the 4‐km cycling time trial followed by the 4‐km cycling time trial test. The test beverage will also be provided 60 min into the 120‐minute exercise test. Outcome measures will be taken before, during and after the time trial. There will be a 7 days’ washout period after each trial. Female participants taking contraceptive pills will be able to come in for the main trial during days 3‐7 of their placebo; those not taking any contraceptives will be required to come during the early follicular phase (days 3‐7); therefore, there will be longer duration between study visits for female participants.

P CONDITION:

Mental Health;Exercise Performance; ; Mental Health ; Exercise Performance Musculoskeletal ‐ Normal musculoskeletal and cartilage development and function

PRIMARY OUTCOME:

Plasma nitrate levels will be assessed to evaluate the bioavailability of these compounds in the beverage[Blood samples (6ml; venepuncture) will be taken at the familiarization trial and during the main trial before the drink is ingested (‐2.5h), immediately pre‐exercise (0h), post‐exercise ( 1h) to assess plasma nitrate and nitrite. ] The main primary outcome is the 4‐km time trial (TT) performance [Time taken to complete the 4‐km TT as well as the mean watts throughout the 4‐km TT] Plasma nitrite levels will be assessed to evaluate the bioavailability of these compounds in the beverage[Blood samples (6ml; venepuncture) will be taken at the familiarization trial and during the main trial before the drink is ingested (‐2.5h), immediately pre‐exercise (0h), post‐exercise ( 1h) to assess plasma nitrate and nitrite. ]

SECONDARY OUTCOME:

Feeling scale will also be evaluated as part of the perceptual measures for the participants[The feeling scale will be measured before (0 h), during (30 min intervals), and after the exercise test.] The felt arousal scale will also be evaluated as part of the perceptual measures for the participants[The felt arousal scale will be measured before (0 h), during (30 min intervals), and after the exercise test (2.5 h).] Heart rate will be measured using a heart rate monitor. [Heart rate will be measured continuously during exercise] Ratings of perceived exertion will be evaluated as a part of the perceptual measures for the participants[Ratings of perceived exertion will be measured before (0 h), during (30 min intervals), and after the exercise test ]

INCLUSION CRITERIA:

Participants must be proficient in English and must be between the ages of 18‐45 years old. They should be well trained and be able to cycle at a moderate intensity for 120 min and also complete a 4 km timed trial.