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Wearable sensors are a rich source of data for researchers

Tampere University
LocationKorkeakoulunkatu 1, Tampere
Hervanta campus, Tietotalo building, lecture hall TB109
14.2.2020 12.00–16.00
Entrance feeFree of charge
Julia Pietilä
The last few years have seen an upsurge of interest in wearable sensors, such as smartwatches and rings, that monitor and quantify our well-being. So far, the data collected by wearable sensors has rarely been used for research purposes. In her doctoral dissertation, MSc (Tech) Julia Pietilä explores the applicability of sensor data for research purposes and, in particular, looks into the monitoring of sleep and physical activity.

As the wearables offer an effective way to collect vast amounts of data, they can provide a wealth of valuable information about our well-being for researchers. To carry out her study, Julia Pietilä analysed data collected by Firstbeat Technologies Oy on the heart rate variability of more than 52,000 Finnish employees.

The unobtrusive sensors intended for everyday wear are a rich source of data that can be used to practically verify the findings of previous research. In addition, the data opens up new perspectives for further research. 

“One of my research questions focused on the effects that alcohol has on sleep. The sensor data confirmed the findings of previous studies, namely that alcohol has a negative effect on our recovery while we are asleep. As the data concerns such a large number of people, the study yielded interesting additional results: alcohol has a similar effect on the sleep quality of both old and young people. Young age appears to offer no protection from the detrimental effects of alcohol on sleep. In previous studies, the number of research subjects has been too small to address this question,” says Julia Pietilä.  

While Pietilä’s observations provide intriguing new avenues for further research, wearable sensors can also provide important information from a practical perspective.  

“The data collected via wearable sensors opens up new possibilities for examining and observing the daily behaviour of people, but it can also help uncover potential solutions for improving human well-being,” Julia Pietilä sums up the practical contributions of her research.

Julia Pietilä was born in Pori, Finland, and spent her youth in Lempäälä. She received funding from the Doctoral School of Tampere University of Technology while working on her dissertation. 

The doctoral dissertation of MSc (Tech) Julia Pietilä in the field of biomedical engineering titled Quantification of Physical Activity and Sleep Behaviors with Wearable Sensors – Analysis of a Large-Scale Real-World Heart Rate Variability Dataset will be publicly examined in room TB109 in the Tietotalo building on the Hervanta campus of Tampere University (address: Korkeakoulunkatu 1, Tampere, Finland) on at 12 noon on Friday 14 February 2020. t. The opponent will be PhD Marco Altini from the company HRV4Training based in the Netherlands.  The Custos will be Ilkka Korhonen, docent in the Faculty of Medicine and Health technology at Tampere University.

The dissertation is available online at