ActiGraph and Short-term Heart Rate Variability Study Protocol: Amended for the COVID-19 Pandemic

ActiGraph accelerometry is widely used in nursing research to estimate daily physical activity. Heart rate variability (HRV), a measure of autonomic modulation, can be assessed in conjunction with the ActiGraph using a Polar H7 Bluetooth heart rate monitor. There is a paucity of nursing literature to guide nurse researchers' protocol development when using the ActiGraph to assess both physical activity and short-term HRV via its Bluetooth capabilities.

The aim of this study was to describe a standardized research ActiGraph and HRV (ActiGraph HRV) protocol for an ongoing randomized controlled trial to measure physical activity and short-term HRV in patients with ischemic heart disease who report hopelessness.

We outline the study protocol for the standardization of reliable and rigorous physical activity and HRV data collection using the ActiGraph wGT3X-BT and Polar H7 Bluetooth heart rate monitor, and data analysis using ActiLife and Kubios software programs.

Sixty-four participants enrolled in the randomized controlled trial to date, and 45 (70.3%) have completed or are actively participating in the study. Heart rate variability data have been collected on 43 of the 45 participants (96%) to date. During the first data collection time point, 42 of 44 participants (95.5%) wore the ActiGraph for a minimum of 5 valid days, followed by 28 of 31 participants (90.3%) and 25 of 26 participants (96.2%) at subsequent data collection time points. The intraclass correlation for physical activity in this study is 0.95 and 0.98 for HRV.

Revisions to the protocol were successfully implemented at the onset of the COVID-19 pandemic for data collection using social distancing. The protocol was additionally amended in response to an unanticipated problem with ActiGraph battery life using Bluetooth technology. Use of the ActiGraph HRV protocol has led to a reliable and rigorous measurement of physical activity and HRV for patients with ischemic heart disease who report hopelessness in this randomized controlled trial.

We provide an ActiGraph HRV protocol that can be adapted as a model in the development of ActiGraph HRV protocols for future nursing research in community and home-based settings while maximizing social distancing in the current and future pandemics.