Menopause and ageing bring several changes to women's health, partly due to a decline in the hormone estrogen. This reduction affects multiple systems in the body, including muscles and bones, and also influences the production of nitric oxide, a molecule that plays a key role in regulating blood flow and blood pressure. An reduced ability to produce nitric oxide is associated with higher blood pressure and an increased risk of cardiovascular and metabolic diseases.
Many women also experience lower levels of physical activity and changes in body composition during midlife, such as increased body fat and reduced muscle mass and strength, which may further decrease exercise capacity.
This PhD project investigates whether a simple, natural strategy, combining exercise with beetroot juice, can help postmenopausal women achieve greater benefits from exercise. Beetroot juice is naturally rich in nitrates, which the body can convert into nitric oxide, thereby enhancing blood flow. Exercise itself also stimulates nitric oxide production, and together these approaches may have additive or even synergistic effects.
The study examines whether consuming beetroot juice before exercise can enhance training adaptations and health outcomes in postmenopausal women. Key outcomes include cardiovascular function, body composition, musculoskeletal function, and aerobic capacity.
Some evidence suggests that beetroot juice may amplify the body's response to exercise, which could be particularly beneficial for postmenopausal women, who often face greater barriers to physical activity. By exploring this combined approach, the project aims to evaluate a safe, non-pharmacological strategy to improve physical function and overall health in women after menopause.
Self-reported biological female and postmenopausal (≥12 months of amenorrhea)
Aged 50-70 years
Body mass index (BMI) 25-39.9 kg/m²
No contraindications to exercise
Known allergy to nitrates or beetroot juice
Current smoker or use of nicotine/tobacco products
Resting blood pressure <90/60 mmHg
Hypertension greater than stage II (≥160/100 mmHg, ESH criteria)
Parallel
Beetroot Juice (Beet-It Stamina Shot) & Supervised Exercise Training
Dietary supplementIntervention includes 3 sessions per week of combined strength and resistance exercise. Two of the sessions are supervised, while the third session is unsupervised-home-based.
Maximal oxygen uptake
Maximal oxygen uptake (VO₂max) will be measured using a standardized incremental exercise test to volitional exhaustion on a cycle ergometer, with continuous analysis of expired gases (indirect calorimetry). VO₂max will be determined as the highest VO₂ value achieved during the test and reported as ml/min and ml/kg/min. Validity of test will be determined based on established criteria such as a plateau in oxygen uptake despite increasing workload, a respiratory exchange ratio above a predefined threshold (e.g., ≥1.10), and/or attainment of age-predicted maximal heart rate. When a clear plateau is not observed, the highest recorded VO₂ (VO₂peak) will be reported.
Skeletal muscle strength
Maximal upper- and lower-body strength will be determined using a Keiser pneumatic leg press and chest press machine as well as handgrip dynamometer using standardized protocols. Maximal strength for will be defined as the highest load achieved and will be reported in kilograms (kg).
Exercise economy
Exercise economy will be assessed during a standardized incremental lactate threshold test using indirect calorimetry. Oxygen consumption (VO₂) will be measured during submaximal exercise stages below the lactate threshold, and exercise economy will be defined as the steady-state oxygen cost at a given absolute workload. Exercise economy will be reported as oxygen consumption relative to workload (e.g., mL·kg-¹·min-¹ or L·min-¹ at a standardized power output or speed), with lower oxygen cost indicating better exercise economy.
Lean mass
Lean mass changes will be assessed using validated body composition analysis methods, including dual-energy X-ray absorptiometry (DXA), according to site-specific standard operating procedures. Measurements will be performed at baseline and after 12 weeks of exercise training under standardized conditions. Total and regional lean mass will be measured and reported in kilograms and % of total mass.
Resting blood pressure
Resting blood pressure control will be assessed after \>15 minutes of supine rest under standardized condition by measuring systolic and diastolic blood pressure five times during a 10 minute resting period, with at least one minute between measurements. A validated automated device will be used. The average of five systolic and diastolic blood pressure measurements will be used for reporting and is reported in mmHg.
Arterial stiffness
Arterial stiffness will be assessed by carotid-femoral pulse wave velocity (cfPWV) in accordance with established expert consensus guidelines. Pulse wave velocity will be determined from the transit time of the arterial pulse waveform between the carotid and femoral arteries, measured in the supine position following a standardized rest period. Arterial stiffness will be reported as cfPWV in meters per second (m/s), with higher values indicating greater arterial stiffness.
Endothelial function
Endothelial function will be assessed by brachial artery flow-mediated dilation (FMD) in accordance with current expert consensus guidelines. FMD will be measured using high-resolution ultrasound following a standardized period of forearm occlusion and subsequent reactive hyperemia. Endothelial function will be quantified as the percentage change in brachial artery diameter from baseline to peak post-occlusion diameter and reported as FMD (%), with higher values indicating better endothelial function.
Pelvic floor strength
Pelvic floor muscle strength will be assessed using a vaginal pressure manometer (Camtech manometer). Participants will be examined in a supine position and covered with a towel for privacy. A small pressure-sensitive vaginal probe will be inserted into the vagina, and participants will perform three maximal voluntary pelvic floor muscle contractions. The highest recorded value will be used for analysis and reported in cmH₂O, with higher values indicating greater muscle strength. The Camtech manometer has demonstrated validity and normative reference values are available for the relevant age group.
Fat mass
Fat mass changes will be assessed using validated body composition analysis methods, including dual-energy X-ray absorptiometry (DXA), according to site-specific standard operating procedures. Measurements will be performed at baseline and after 12 weeks of exercise training under standardized conditions. Total and regional fat mass will be measured and reported in kilograms and %.
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