Background: Obesity and reduced muscle strength are associated with increased blood pressure (BP). We examined the impact of milk proteins and combined exercise training (CET) on BP, arterial function, and muscle strength (one-repetition maximum (1-RM)).
Methods: Thirty-three obese sedentary women (age = 30 ± 1 years; body mass index = 35.2 ± 0.9 kg/m(2); systolic BP (SBP) = 129 ± 2 mm Hg) were randomized to control carbohydrate (n = 11), whey (n = 11), and casein (n = 11) supplementation for 4 weeks. All participants performed moderate-intensity CET 3 days/week. Brachial and aortic SBP, augmentation index adjusted for 75 beats/minute (AIx@75), arterial stiffness (brachial-ankle pulse wave velocity (baPWV)), and 1-RM were measured before and after the interventions.
Results: There were significant (P < 0.05) time-by-group interactions for brachial SBP (bSBP), aortic SBP (aSBP), AIx@75, and baPWV. Whey and casein supplementation significantly (P < 0.05) decreased bSBP (approximately 5mm Hg for both), aSBP (approximately 7 mm Hg and approximately 6mm Hg, respectively), AIx@75 (approximately 9.2% and approximately 8.1%, respectively) and baPWV (approximately 57 cm/s and approximately 53 cm/s, respectively) compared with no changes in the control group. Upper- (approximately 22.2%) and lower-body 1-RM (approximately 44.0%) increased similarly in all groups. Changes in arterial function and 1-RM were not correlated.
Conclusions: Milk protein supplementation with CET reduced SBP, wave reflection, and arterial stiffness in young obese women with prehypertension and hypertension. Because CET did not affect arterial function, milk proteins may have an antihypertensive effect by improving arterial function, as shown by reduced AIx@75 and baPWV. Muscle strength improvements after CET did not affect BP and arterial function.
Clinical trial registration: ClinicalTrial.gov Registration NCT01830946.
Keywords: aortic blood pressure; augmentation index; blood pressure; casein; hypertension; muscle strength; pulse wave velocity; wave reflection; whey..