The study was published in the scientific journal The Lancet. Data from more than 8 million randomly selected wearables users over a 24-hour period were needed to conduct this research on heart rate variability.
The study was published in December in the British journal under the title: “Heart rate variability with photoplethysmography in 8 million individuals: a cross-sectional study”. Among their main findings found through data obtained by wearables were that low-frequency power varies significantly between sexes, and the researchers observed an association between physical activity and heart rate variability metrics.
The study explains that heart rate variability (the variation in the time interval between heartbeats), is a dynamic metric of the autonomic nervous system and one of the independent risk factors for cardiovascular death. Wearables or wrist devices are a useful tool for collecting this type of data; the wearables used in this study have photoplethysmography, which allows measuring and monitoring the substitutes of the nervous system activity through the analysis of the intervals between heartbeats. In response, the scientists explained that “we aimed to leverage wrist-worn trackers to derive and describe diverse measures of cardiac autonomic function among Fitbit device users (devices)”.
As this is a cross-sectional study, which includes statistical, demographic, and epidemiological data, the intervals between heartbeats were collected over a randomly selected 24-hour period from more than 8 million people. For the accuracy of the study, data from 90 days prior to the steps performed per day were collected, in addition to other essential data such as sex, BMI and age. Other parameters used for the heart rate variability (HRV) variable were rMSSD and SDRR.
“Data from participants were analysed to establish the correlation between heart rate variability metrics and age, sex, time of day, and physical activity. We also determined benchmarks for heart rate variability (HRV) metrics among the users,” they explain in the text.
To learn more about the processes and results of this study you can consult for free through the following link: https://www.thelancet.com/journals/landig/article/PIIS2589-7500(20)30246-6/fulltext#seccestitle140
