The Use of Small Electronic Devices and Health: Feasibility of Interventions for a Forthcoming Crossover Design

Lisbeth Hoekjaer Larsen*, Maja Hedegaard Lauritzen, Sirin Wilhelmsen Gangstad, Troels Wesenberg Kjaer

*Corresponding author for this work

Research output: Contribution to journalJournal articleResearchpeer-review

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Modern lifestyle is heavily affected by technology such as smartphones, tablets, and other small computers; yet it remains unclear how our health and well-being are affected by the heavy use of these devices. This feasibility study aims to test two different interventions of an experimental protocol for a forthcoming large-scale community-based study and get estimates of parameters for sample size calculation. The aim of the large-scale study is to investigate the effect of (1) a wearable tracking device on aerobic capacity (VO2max/kg) and the effect of (2) restricting media use on total sleep time. Twenty healthy participants were included and equipped with a wrist-worn device tracking physical activity and sleep. Participants were allocated to either a physical activity group, which was instructed to use the wrist-worn device to support exercise, or a sleep silent group, which was instructed to remove or switch off all electronic devices in the bedroom (except the wrist-worn tracking device). The intervention lasted approximately 4 weeks. Data collected included blood pressure, submaximal cycle ergometer test, self-reported technology use, and compliance of using the wearable tracking device. All participants wore the wearable tracking device 95.8% (SD 4.4%) of the time. Participants in the physical activity group increased aerobic capacity from 30.38 (SD 8.98) to 32.1 (SD 8.71) mL/kg/min (t=-2.31, P=.046) and decreased their systolic blood pressure from 126.5 (SD 15.8) mm Hg to 121.8 (SD 11.7) mm Hg (t=2.72, P=.02). The sleep silent group prolonged their time offline before bedtime from 18.1 (SD 19.4) minutes to 27.2 (SD 17.3) minutes (t=-2.94, P=.02). The two interventions are feasible to conduct. Participants were willing to wear the tracking device on their wrist and restrict all media use in their bedroom and thereby reduce bedtime technology use. Our results also suggest that tracking physical activity using a wearable device is accompanied by noteworthy health benefits. We outline necessary adjustments for a forthcoming large-scale study.
Original languageEnglish
Article numbere20410
JournalJMIR Formative Research
Issue number1
Number of pages9
Publication statusPublished - 2021


  • Accelerometer
  • Activity trackers
  • Aerobic capacity
  • Insufficient sleep
  • Media use
  • Screen time
  • Sleep problems
  • Smartphones
  • Wearable tracking devices

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