The impact of moderate intensity physical activity on cardiac structure and performance in older sedentary adults

Abstract

BackgroundSedentary aging leads to adverse changes in vascular function and cardiac performance. We published improvements in vascular function with moderate intensity physical activity (PA) in continuous bouts. Whether moderate intensity PA also impacts cardiac structure and cardiovascular performance of the aging left ventricle (LV) is unknown.MethodsWe recruited and analyzed results from 102 sedentary older adults ages ≥ 50 from a randomized controlled trial with 3 study groups: control (group 1), a pedometer-only intervention (group 2), or a pedometer with an interactive website employing strategies to increase habitual physical activity (PA, group 3) for 12 weeks. Transthoracic echocardiograms were performed prior to and following the 12 week intervention period to assess cardiac morphology, left ventricular (LV) systolic performance, LV diastolic function, and arterial and LV ventricular elastance. Step count and PA intensity/distribution were measured by a pedometer and an accelerometer.ResultsWe found no significant changes in cardiac morphology. Further, we found no improvement in the aforementioned cardiac functional parameters. Comparing those who achieved the following benchmarks to those who did not showed no significant changes in cardiac structure or performance: 1) 10,000 steps/day, 2) ≥ 30 min/day of moderate intensity physical activity, or 3) moderate intensity PA in bouts ≥ 10 min for ≥ 20 min/dayConclusionsIn sedentary older adults, increasing moderate intensity PA to currently recommended levels does not result in favorable changes in LV morphology or performance over 12 weeks. More prolonged exposure, higher PA intensity, or earlier initiation of PA may be necessary to see benefits.

Pattern Analysis of Sedentary Behavior Change after a Walking Intervention

“…Full methods and design of each randomized controlled trial have been described in detail elsewhere. 24,25 Briefly, each study recruited older adults (≥50 and ≤ 80 years of age) that were community dwelling, inactive, but in relatively good health with no uncontrolled cardiovascular or metabolic disease. Specific inclusion and exclusion criteria were previously reported.…”

“…24,25 Study 1 included a sample of 61 25 and Study 2 included a sample of 107. 24 All older adults accumulated less than 8000 steps/day over a one-week blinded baseline pedometer assessment period, with group means ranging from 4931±1667 to 5474±1512 (mean ± SE) steps/day. Both randomized controlled trials had an intervention group (STEP) and a control group (CON).…”

Can consumer wearable activity tracker-based interventions improve physical activity and cardiometabolic health in patients with chronic diseases? A systematic review and meta-analysis of randomised controlled trials

“…Among the 35 included studies, several increased risks of bias were assessed. Fifteen studies met five (n = 5) [37,42,57,59,65] and four (n = 10) [18,33,38,41,49,53,55,58,64,66] of the six risk of bias criteria. Eighteen studies met three criteria [32, 34-36, 39, 40, 43-45, 47, 50-52, 56, 60-63] and two studies met only two criteria [48,54].…”

“…The majority of the interventions consisted of CWAT use and individual counselling (n = 22) of which five interventions also used additional telephone calls [48,51,[59][60][61]. Control conditions varied between studies and consisted of usual care (n = 21) [32, 34-36, 38, 41-43, 46-50, 52-56, 58, 59, 61], maintaining normal physical activity levels (n = 7) [39,57,[62][63][64][65][66], encouragement to increase daily physical activity (n = 2) [37,40], generic information brochures (n = 1) [51], education sessions (n = 2) [33,44], coaching sessions (n = 1) [45] and one control group wore masked CWAT devices (n = 1) [60]. Furthermore, the average dropout rate among the studies was 17% (range: 0-43%) of which four studies had a 100% participants completion rate.…”

The effects of graded changes in oxygen and carbon dioxide tension on coronary blood velocity independent of myocardial energy demand

“…Recently, an index of left ventricular (LV) function has been developed using a noninvasive estimation of myocardial elastance that allows an investigator to assess the elastic potential energy of the heart (7). This index is well correlated with invasive measures of myocardial contractility and has been adopted for clinical assessments of LV function (38,40,52). Along with noninvasive LV pressure and volume estimations, it can be used to generate noninvasive pressure volume relationships, which might provide a less variable index of total mechanical energy than RPP.…”