Effects of Beetroot Juice in Postmenopausal and Hypertensive

N/ACompletedNCT03620227

Federal University of Uberlandia13 enrolled

Overview

The decrease in estrogen in postmenopausal women leads an increase in endocrine metabolic dysfunctions, such as changes in lipid profile and blood pressure. Thus, one of the alternatives for prevention and treatment is the practice of physical exercise associated with diet containing precursors of nitric oxide (NO), which is a potent vasodilator. Therefore, this study intends to verify if supplementation of beetroot juice changes the hemodynamic and salivary markers in postmenopausal and hypertensive women. Therefore, the intervention consists of 350ml of concentrated beetroot juice or placebo, which will be ingested in fasting. After 2 hours will be carried out a session of aerobic physical exercise in treadmill and blood pressure will be measured each 15 minutes for 90 minutes after the end of the session, in addition to the 24-hour measurement that will be performed by an ABPM device. Salivary samples will be held: before the juice ingest, right after exercise, 90 minutes after and 24 hours after the end of the exercise. With the development of this study, it is expected to find blood pressure reduction and normalization of the inflammatory profile through salivary samples, after the period of supplementation associated with physical exercise practice.

The intervention protocol will last 3 days. On the first day there will be the collection of anthropometric data, the signature of a consent term and delivery of the list of foods that should be avoided 24 hours before the tests and a treadmill familiarization. On the second and third day the physical intervention will be performed associated with juice or placebo supplementation. A wash out period of at least 7 days will be performed between the second and third day. The volunteers will arrive at the laboratory at 7am in the fasted state and will be rested until 07:20am and then the blood pressure (BP) measurement (collected three times, with an interval of 1 minute between measurements), collection of the saliva and the measurement of heart rate (HR). Approximately at 07:30am they will start drinking the juice and will have up to 15 minutes to consume. BP will be measured at 08:00am, 08:30am, 09:00am and 09:30am. At 9:30am a physical exercise session will begin, during which will be monitored by a cardio-frequency monitor, which will remain until 11h10am (period referring to the end of BP monitoring in the laboratory). At 10:10am the workout will be finished, and then the saliva will be collected. After this period, the volunteers can take up to 250 ml of water until 11:10am, and every 15 minutes, BP will also be measured. and at 11:10am a collection of saliva will be performed. The volunteers will have the period of 15 minutes to be hygienised, and at 11:25am the ABPM will be placed (ambulatory blood pressure monitor). The ABPM will be taken the day after the test at 10:10 am (time for the first post-exercise BP measurement), and the last collection of saliva will be carried out concurrently with the ABPM removal.

Interventions

ExerciseOTHER

40 minutes of aerobic exercise on a treadmill, with a fixed speed of 5.5 km/h and intensity imposed by treadmill inclination until it reaches the frequency zone between 60% and 75% of the reserve heart rate.

Beetroot juiceDIETARY_SUPPLEMENT

Ingestion of 350ml of concentrated beetroot juice (400mg of nitrate) 100 minutes before an exercise session.

PlaceboDIETARY_SUPPLEMENT

Ingestion of 350ml of placebo (0mg of nitrate, with the same color, taste and smell) 100 minutes before an exercise session.

Eligibility

Sex: FEMALEMin age: 50 YearsMax age: 70 Years

Medical Language ↔ Plain English

Inclusion Criteria: * Women aged between 50 and 70 years; * Amenorrhea of at least 12 months; * Being in the postmenopausal phase; * Be controlled hypertension; * Be able to practice physical exercises on cycle ergometers; * Submit a certificate attesting to the ability to practice physical exercises. Exclusion Criteria: * Be uncompensated hypertensive in stages 2 and 3; * To present a history of stroke or acute myocardial infarction; * Be a smoker; * To present physical problems or cardiovascular complications that prevent the performance of physical exercises. * To present a diagnosis of Diabetes Mellitus; * To present renal pathologies; * To present gastrointestinal pathologies; * Have hypersensitivity to nitrate; * Make use of hormonal therapies.

Outcomes

Primary Outcomes

Changes in rest Blood Pressure

After 15 minutes of total rest, Systolic, Diastolic and Mean blood pressure will be measured by automatic device 3 times with one minute between measurements.

Time frame: Before and 15, 30, 45 and 60 minutes after exercise sessions

Changes in Ambulatorial Blood Pressure

All volunteers were submitted to a 24-hour Blood Pressure (BP) assessment by Ambulatorial Blood Pressure Monitoring (ABPM) 60 minutes after exercise. A device was used associated with a diary of examination to self-report of activities of daily living (sleep, work, food) or any event that could interfere abnormally with BP or device measurements. The device was always placed 7am and the measurements were made every 15 minutes from 7h to 23h and every 30 minutes from 23h to 7h. The monitoring was considered valid when it happened for a period of 24 hours. The following results were evaluated: systolic blood pressure; diastolic blood pressure, mean blood pressure and heart rate in awake, sleep and 24-hour periods.

Time frame: Every 15 minutes during 24 hours from 60 minutes after exercise

Secondary Outcomes

Changes in Heart Rate Variability

Heart Rate (HR) was recorded using a heart rate monitor in a beat-by-beat basis. HR was registered in a seat position for 20 min of rest. Prior to the HR Variability (HRV) analysis, the RR intervals (RRi) were visually inspected and filtered using a moving average filter. The HRV was analyzed in both time-, frequency- and nonlinear-domain. Being that for frequency-domain analysis, firstly the RRi series were interpolated at 4 Hz and then the signal linear trend component removal was performed using the smooth priors approach.

Time frame: During the 20 minutes before and after the exercise and during the execution of the exercise.

Changes in salivary oxidative stress

The salivary was collected after 12-hours fasting and the total antioxidant capacity was evaluated using the Ferric-Ability of Plasma (FRAP) methodology and calculated from the standard trolox curve. The activity of the enzyme superoxide dismutase (SOD) was determined based on the auto oxidation capacity of pyrogallol and catalase activity (CAT) by monitoring the consumption of hydrogen peroxide at 240 nm. Lipid peroxidation levels were determined by the TBARS method (thiobarbituric acid reactive substances), using as standard a curve of 1,1,3,3-tetraethoxypropane (TMP). The total protein concentration was obtained by the Bradford method (BRADFORD, 1976), using bovine serum albumin (BSA) as standard. The amounts of nitric oxide (NO) were estimated by the determination of total nitrite by the Griess colorimetric method.

Time frame: Before supplementation, right after, 60 minutes and 24 hour after exercise sessions

Changes in Ambulatorial Blood Pressure Variability

Based on Systolic, Diastolic and Mean Ambulatorial Blood Pressure data, were calculated Blood Pressure Variability by: 24-hour standard deviation weighted by the time interval between consecutive readings; the mean diurnal and nocturnal deviations weighted for the duration of the daytime and nighttime interval; the average real variability weighted for the time interval between consecutive readings; the ambulatory arterial stiffness index calculated by the slope of the trend curve of the dispersion of pressure data; the morning surge that represents the dynamic daytime variation in morning pressure that tends to increase, being assessed from the point of least pressure during sleep in relation to the first two hours after waking; and nocturnal dipping, that represents the average percentage drop of sleep pressure in relation to wakefulness, and individuals with falls of 10% or more are considered dippers and below that are considered nom-dippers.