Investigating the Combined Effects of Protein, Blueberries, and Exercise on Cardiovascular Health and Frailty in Older Nova Scotians

Overview

Cardiovascular diseases (CVD) are a leading cause of morbidity and mortality worldwide. While CVDs are predominantly diseases of aging, age itself does not predict CVD risk; people age at different rates. Frailty is a state of accelerated aging that increases the risk of adverse health outcomes. Frail people are at higher risk of developing CVDs, experiencing complications, and dying from these diseases than fit people of the same age. Indeed, frailty predicts the likelihood of developing CVD independently of traditional risk factors for CVD. It is known that older women are frailer than men and tend to express CVDs differently than men, but whether relationships between frailty and CVD are sex specific is unclear. It is possible that shared pathophysiological mechanisms such as chronic inflammation may help explain links between CVD and frailty. Importantly, the degree of frailty can be modified by lifestyle interventions. For example, sedentary lifestyles, food insecurity, and suboptimal dietary habits can exacerbate frailty whereas diet and exercise interventions can attenuate frailty. The investigators propose that a comprehensive health strategy targeting diet and physical activity to reduce frailty will reduce the risk of cardiovascular disease (CVD), thereby promoting healthy aging. Engaging in physical activity (e.g. exercise) helps improve aerobic fitness, increase muscle mass, promote cardiac regeneration, enhance metabolic function, regulate blood pressure, improve insulin sensitivity, reduce inflammation (a key frailty mechanism), and lessen frailty. High-quality dietary protein is essential to maintain muscle mass/function, preserve mobility, attenuate inflammation, and reduce frailty. Packed with antioxidants such as anthocyanins and flavonoids, with high levels of fiber, vitamins, and minerals, blueberries, a local Nova Scotian food, can help lower blood pressure, improve blood vessel function, reduce inflammation, and help the body utilize dietary protein. These are critical aspects of a strong heart and healthy aging. To date, many frailty intervention studies have been limited by small sample sizes, underrepresentation of women, and/or by testing individual lifestyle modifications rather than synergistic effects; additionally, none have investigated how reducing frailty impacts cardiovascular outcomes. Our goal is to determine if a year-long multidomain intervention of protein, blueberries, and exercise reduces frailty and cardiovascular disease risk in older at-risk Nova Scotians of both sexes.

The proposed trial is a randomized control trial (RCT) investigating the synergistic effects of protein, blueberries, and resistance plus aerobic training on frailty and cardiovascular health in at-risk Nova Scotians. As frailty and CVD are closely linked, the investigators propose that lifestyle interventions to reduce frailty will improve cardiovascular health in at risk individuals. Studies designed to reduce frailty to date are limited by testing individual lifestyle modifications rather than a prescribed package combining theoretically synergistic treatments and none have investigated effects on cardiovascular health. The investigators have developed a novel packaged intervention of exercise plus protein and blueberries based on their effectiveness as individual treatments and potential for synergy based on complementary biological mechanisms. The investigators will determine whether this prescribed STRONG intervention reduces frailty and improves cardiovascular health in older Nova Scotians by comparing the treatment group with a control group who will receive their usual medical care, as in most pragmatic trials that are performed to determine if an intervention can improve current practice. Usual medical care may differ between participants; it may or may not include diet and exercise recommendations from their physicians. The trial design for the STRONG study is a pragmatic randomized controlled trial on year in length with an additional year of follow-up. The participants will be randomly assigned to one of two groups for 12 months: the control group (n=120 who will receive usual care), or the treatment group (n=120; who will receive the STRONG intervention of protein, blueberries, and exercise). The control group will be tested for fitness, frailty, and cardiovascular health including blood biomarkers and cardiac function (echocardiography). Both groups will be given the option to review their assessment results at each timepoint. Exercise intensity will be monitored using the Category Ratio 10 (CR10) ratings of perceived exertion scale. On this scale, exercise should elicit a score of 4-5. All participants will be given a copy of the CR10 scale and taught how to use it. The exercise prescription will be individualized to each participant based on their pre-intervention fitness level, level of frailty and medical history. Progression of the program will be determined on an individual basis. All exercise programs will be designed and supervised by a clinical exercise physiologist. A hybrid approach will be used for the exercise sessions. The participant must attend the first exercise session in person and then can choose to attend subsequent sessions in person (Exercise Lab, Dickson Bldg) and/or virtually. All virtual sessions will be delivered via a secure Nova Scotia Health Zoom link. Having the first session in person gives all participants the opportunity to learn and discuss the exercises in a one-on-one format with the clinical exercise physiologist. After the first session it is expected that there may be multiple study participants in in-person or virtual exercise sessions. It is hypothesized that the addition of blueberries to a regimen of exercise plus protein will have synergistic beneficial effects on frailty and cardiovascular health in older individuals. Our objectives are: 1. To determine whether the STRONG intervention reduces frailty equally in both sexes. 2. To determine whether this intervention improves cardiovascular health in males and females. 3. To determine whether beneficial effects of this intervention are mediated, in part, by effects on markers of chronic inflammation and whether these effects are sex specific