Maud Vroemen

The aim of this dissertation was to investigate the multidimensional effects of mobile usage on general health. The results of this research are alarming and should raise concerns. Whether it is using a mobile phone on a daily basis, the radiation as emitted from one single SMS or the effects of two images of opposite emotional valence, heart rate variability is affected. As a biomarker which is indicative for overall health, heart rate variability is continuously exposed to mobile phone usage in the digital age and thus is society’s wellbeing.

In Chapter 2 baseline ECG recordings and a questionnaire to classify mobile phone usage, corrected for STAI-TRAIT and CES-D, a negative association between mobile phone usage and heart rate variability was found. Even though data was gained with 3G network mobile phones, these results raised concerns for more modern mobile phones, operating on 5G and future networks.

Chapter 3, in which the direct effects of mobile phone radiation on heart rate variability was investigated, showed alarming results. In this N = 1 study SMSes were sent to a mobile phone close to the participant, while ECG recordings were made. In other words, this single subject design can be seen as a proof of principle study and therefore invited to broaden further research into the various effects of mobile phone usage.

In Chapter 4 a redesigned mood induction procedure is described. This experiment showed that participants who were exposed to two images of opposite emotional valence, subjective mood was affected in the same direction. This procedure was set up to create an experiment as close to reality as possible including quickly changing emotions, as happening during mobile phone usage.

Chapter 5 described an experiment in which the mood induction procedure of chapter 4 was used. The same method was used, there was only one big difference, namely additional ECG recordings during the procedure. The results were quite significant. Whereas subjective mood was affected in the same direction as the emotional valence of the images, counter-intuitively, HRV was influenced differently. To be specific, the impact of the first image on HRV continued over exposure to the second image, where a flip-over effect of HRV was expected. Thus, keeping in mind emotions are changing continuously during mobile phone usage, effects of changing emotions on HRV during usage can potentially be expected as well.

In an observational study (which was prematurely stopped due to the Covid-19 outbreak), which is described in Chapter 6, the self-reported health within 5-11 year olds of a Dutch primary school was examined. A negative association between intensity of Touch Screen Device usage and health outcomes was found. The alarming results found in this relatively small N study, strongly encourage to set up a new and more extensive study.

All in all, since lower levels of HRV suggest poorer health outcomes and mobile phone usage today exists from beginning to end, the results mentioned before should raise public concern. In this digital age where mobile phone usage is completely normalized, everyone should feel addressed regarding the potential unwanted effects of mobile phone usage.

As stated above, the goal of this dissertation was to investigate the effects of mobile usage on general health in the digital age. Whether it is the mobile phone radiation one is exposed to or the emotional contents one faces during regular use, both facets have an influence on heart rate variability. However, conclusions made in this research project only reflect the tip of the iceberg. The call for more extensive research in the future remains. By implementing current research models, more knowledge might be gained on potential dose-response relationships, as well for mobile phone radiation as for overall usage, especially when examined from the very first beginning children start using a mobile phone.