Effects of handgrip exercise or inorganic nitrate supplementation on 24-h ambulatory blood pressure and peripheral arterial function in overweight and obese middle age and older adults: A pilot RCT

Introduction: Hypertension is a major contributor to the global burden of cardiovascular diseases and its prevalence increases progressively with ageing. Therefore the identification of effective, age-friendly exercise and nutritional interventions which lower blood pressure (BP) is a research priority. Objective: To undertake a pilot RCT examining the efficacy of isometric handgrip exercise (IHGE) and beetroot juice (a rich source of inorganic nitrate) consumption in modifying clinic and 24-h ambulatory BP (24-h ABP), peripheral arterial function and plasma asymmetric dimethylarginine (ADMA) in older overweight and obese adults. Design: Thirty middle age and older adults (62 ± 5 years) were randomised to: (a) bilateral IHGE at 50% of maximal voluntary contraction (8 min/day), (b) 140 ml/day of concentrated beetroot juice, or (c) no-intervention (control group), for 7 days. All groups followed a standardised diet to control nitrate intake. Clinic and 24-h ABP, peripheral arterial function quantified by pulse wave velocity (PWV) and arterial volume distensibility were assessed before and after intervention. Setting: Clinical ageing research unit, Newcastle University. Results: At baseline, there were no between-group differences in age, handgrip strength, clinic or 24-h ABP, BMI, waist circumference, fat mass, physical activity level, energy intake or urinary and plasma nitrate concentrations. After intervention, there were no significant effects on clinic systolic and diastolic BP or 24-h ABP, PWV (p = 0.54), arterial volume distensibility (p = 0.89), or ADMA (p = 0.45). Conclusions: IHGE or beetroot juice consumption for 7 days did not affect BP or peripheral arterial function in overweight and obese middle age and older adults. Ageing may reduce the effects of these interventions on vascular function and studies are needed to test this hypothesis.