Physical Activity and Markers of Cardiovascular Health: Understanding the Influence of Menopause and Stroke

Abstract

In females, menopause-related reductions in estrogen may cause declines in cardiovascular health and increase the risk for stroke. In the event of stroke, cardiovascular health of postmenopausal females may be further worsened. It is well established that physical activity and exercise improves cardiovascular health in the general population and in those with chronic conditions, including stroke. However, the nature and extent of the associations between physical activity and cardiovascular health of pre- and post-menopausal females with, and without, stroke are unclear. This thesis is comprised of two studies to address this knowledge gap. The first study was a systematic review to examine the effect of aerobic exercise on cardiovascular health of postmenopausal females, and the association with different exercise intensities. Five electronic databases from inception to May 6th, 2022, were searched for randomized-controlled trials of aerobic exercise interventions reporting cardiovascular outcomes in postmenopausal females. Data was synthesized qualitatively, and random-effects meta-analyses and subgroup analyses (for light, moderate, vigorous intensity) were performed. Fifty-six studies (4134 participants;45-78 years of age) were identified. Aerobic exercise interventions varied in frequency (3-21x/week), intensity, type, time (8-60 min/session), and duration (3-52 weeks). Fifty studies (n=3730) were included in the quantitative synthesis. Aerobic exercise improved systolic blood pressure (SBP) (Mean difference(MD)=-3.67mmHg, 95%CI[-6.88,-0.46],p=0.03), resting heart rate (MD=-5.76bpm, 95%CI[-5.76,-1.61],p<0.01), body mass index (BMI)(MD=-0.65kg/m2, 95%CI[-0.99,-0.31],p<0.01), waist circumference (WC) (MD=-2.03cm, 95%CI[-2.65,-1.41],p<0.01), body fat (MD=-2.57kg, 95%CI[-3.65,-1.49],p<0.01), low-density lipoprotein cholesterol (MD=-10.46mg/dL, 95%CI[-16.31,-4.61],p<0.01), high-density lipoprotein cholesterol (MD=3.28mg/dL, 95%CI[0.20,6.36],p=0.04) and cardiorespiratory fitness (Standardized MD=1.43, 95%CI[1.17,1.70],p<0.01). Subgroup differences in exercise intensity were only present for BMI where light- and vigorous-intensities were beneficial, and moderate intensity had no effect (X2=9.79, df=2,p<0.01), and for blood triglycerides and blood glucose where light intensity showed a beneficial effect and there was no effect of moderate and vigorous intensities (triglycerides X2=7.70, df=2, p=0.02; glucose X2=20.98, df=2, p<0.01). The second study was a cross-sectional analysis of baseline data from the Canadian Longitudinal Study on Aging that examined the association between physical activity and cardiovascular health in females with stroke, and the interaction with menopause. Generalized linear models with applied sampling weights were used to examine the associations between cardiovascular health, and self-reported physical activity, while controlling for age and smoking history. Subsequent models included an interaction between physical activity and menopausal status. The sample included 1468 females with stroke (103 premenopausal). Physical activity was beneficially associated with SBP (ß = -0.02 (SE=0.01), p=0.04, 95% CI: -0.42 to -0.0005), WC (ß = -0.03 (SE=0.008), p<0.01, 95% CI: -0.05 to -0.02), waist-to-hip ratio (ß = -0.00009 (SE=0.00004), p=0.03, 95% CI: -0.0002 to -0.0000007), C-Reactive protein (ß = -0.007 (SE=0.003), p<0.02, 95% CI: -0.013 to -0.001). There were no interactions between physical activity and menopausal status for all outcomes. Together, these studies contribute to the development of future guidelines and research to improve cardiovascular health in underrepresented and high-risk populations of postmenopausal females and females with stroke.