Every step counts in lowering BP
A higher number of daily steps appears to be associated with lower home blood pressure (BP) in middle-aged individuals, according to the electronic Framingham Heart Study (eFHS) presented at the ACC.20/WCC Virtual Meeting.
This electronic cohort study consisted of 638 participants (mean age 55 years, 58.9 percent women), of whom 29 percent had hypertension. The participants were instructed to download and register the eFHS smartphone app, which was synced to their Apple Watch (first generation) and Withings digital BP cuff. All participants wore the watch for 14 hours/day and transmitted a total of 24 BP readings to the FHS Researcher Center. [ACC.20/WCC, abstract 1361-129]
At a median follow-up of 280 days, individuals achieved an average daily step count of 7,531 with a mean home systolic BP (SBP) of 122 mm Hg and diastolic BP (DBP) of 76 mm Hg.
After adjusting for age, sex, family structure, and watch wear time, results showed that every increase of 1,000 steps/day led to a 0.45-point reduction in home SBP level (p=0.015) and a 0.36-point reduction in DBP level (p=0.006).
In an exploratory analysis, after adjusting for body mass index (BMI), the association between daily step count and home BP was no longer significant (0.09 point increase (p=0.58) for SBP and 0.01 point increase (p=0.95) for DBP. A majority of this association appears to be mediated by BMI, said lead author Dr Mayank Sardana from the University of California in San Francisco, California, US, during a consumer web briefing.
Sardana noted that the analysis does not establish causality or directionality of the association, hence the need for future randomized trials to confirm this finding.
“Now, we have smartwatches, which can accurately measure the physical activity over long periods of time that could potentially help us understand the real or habitual patterns of physical activity [and] how those relate to certain cardiovascular phenotypes,” he said.
“I think the overall point [of our study] … is that you should walk more … This study solidifies our understanding of the relationship between physical activity and BP and raises the possibility that obesity or BMI accounts for a lot of that relationship,” added Sardana.“Going forward, it would be useful to look at how smart devices might be leveraged to promote physical activity, reduce the burden of obesity, and potentially reduce BP,” he said.