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Exercise, Weight Loss, Proximal Aortic Stiffness in Older Obese Adults
Quick Takes
- In the study designed to assess the impact of exercise and diet on the aorta, there was no significant correlation between decrease in proximal aortic stiffness and improvement in fitness, blood pressure, weight, and total and visceral fat.
- However, reductions in blood pressure and body fatness with modest caloric restriction added to exercise training appear to have a greater impact on aortic function than improved fitness.
- The study used aortic distensibility as a surrogate for reducing risk of cardiovascular disease in the elderly with moderate obesity. It was not powered to draw conclusions regarding the optimal diet for improving cardiometabolic health and longevity.
Study Questions:
What are the effects of aerobic exercise training with and without moderate- to high-caloric restriction (CR) on the structure and function of the aorta in older men and women with obesity (body mass index [BMI] 30–45 kg/m2)?
Methods:
A total of 160 men and women 65−79 years were randomly assigned to one of three groups: aerobic exercise (EX) training only (treadmill 4 days/week for 30 minutes at 65−70% of heart rate reserve; n = 56), EX + moderate CR (n = 55), or EX + intensive CR (n = 49) for 20 weeks. Aortic pulse wave velocity, aortic distensibility, and other measures of aortic structure and function were assessed by cardiovascular magnetic resonance imaging (MRI). Pearson correlation coefficients were examined to assess associations between changes in proximal aortic stiffness and changes in fitness, fatness, and other potential confounders.
Results:
Mean age was 69 years, with 74% female and 73% White. There were no between-group differences in mean BMI (34.5 kg/m2), weight about 94 kg, measures of body fatness, hypertension, diabetes, or medication use. Weight loss in the EX + moderate CR (−8.0 kg) and EX + intensive CR (−8.98 kg) groups did not differ despite a nearly two-fold greater caloric deficit in the intensive CR (absolute – 499 kcal/day, relative – 26.7%) compared to the moderate CR (absolute –195 kcal/day, relative – 14.2%), but each was significantly greater compared with the EX–only group (−1.66 kg; p < 0.017 for both). Changes in BMI and measures of total and visceral fat were greater in the CR groups compared to EX-only. Measured peak V02 increased by 1.4 ml × kg−1 × min−1 in EX-only, 2.5 in the EX-mod CR and 2.8 in the EX-high CR groups; however, the adjusted peak V02 of about 20 ml × kg−1 × min−1 did not differ between groups. There were significant treatment effects for descending aorta distensibility (p = 0.008) and strain (p = 0.004) and aortic arch pulse wave velocity (p = 0.01) with the EX-training + moderate CR group having a 21% increase in distensibility (p = 0.016) and an 8% decrease in pulse wave velocity (p = 0.058). None of the aortic stiffness measures changed significantly in EX–only or EX–high CR groups; there were no significant changes in any other measure of aortic structure or function in these groups. Overall, increases in aortic distensibility were correlated with improvements in body weight and body fat distribution, but these associations were not statistically significant after adjustment for multiple comparisons. Intervention resulted in a significant reduction in the systolic blood pressure in the EX + mod-CR group (7.9 mm Hg) and in the EX + high-CR group (6.7 mm Hg), but there was no change in the EX-only group.
Conclusions:
In older adults with obesity, combining aerobic exercise with moderate CR leads to greater improvements in proximal aortic stiffness than exercise alone.
Perspective:
The authors suggest that weight loss by modest CR and aerobic exercise may be preferable to exercise alone and exercise with more intense CR in obese elderly persons. That is based on potential risk of more intensive CR and a benefit in proximal aortic stiffness not seen with exercise training alone or exercise plus intensive CR. The use of MRI provides very interesting and more reliable measures of aortic distensibility that includes both the ascending and descending aorta. However, the difference in modest versus more intense caloric reduction was based on a difference of 300 kcal per day and there were no data regarding sodium intake, which has a greater impact on aortic stiffness than exercise. Further, this study was not adequately powered to assess how the hypothesis would be affected by the metabolic syndrome and components. Last, the absence of heart and other vascular disease and kidney disease was based on patient information.
Clinical Topics: Diabetes and Cardiometabolic Disease, Geriatric Cardiology, Noninvasive Imaging, Prevention, Magnetic Resonance Imaging, Diet, Exercise, Hypertension
Keywords: Aorta, Thoracic, Blood Pressure, Body Fat Distribution, Body Mass Index, Body Weight, Caloric Restriction, Diet, Exercise, Geriatrics, Heart Rate, Hypertension, Intra-Abdominal Fat, Magnetic Resonance Imaging, Metabolic Syndrome, Obesity, Primary Prevention, Pulse Wave Analysis, Sodium, Dietary, Vascular Stiffness, Weight Loss
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