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Health changes can be reliably predicted by monitoring the activity level and rhythms of older people


Research Scientist Juho Merilahti of VTT Technical Research Centre of Finland has studied the measurement of physical functioning in older adults, based on logging their physical activity when predicting changes in their state of health. He recommends that the consistency, intensity and uniformity of the activity level and rhythm of older people be measured in parallel, in order to identify possible changes in their state of health.
In his thesis, which will be examined on 15 December, Merilahti investigated the suitability of actigraphy, i.e., the logging of physical activity, for continuously assessing the functional ability of older people in everyday life. He states that measurements must be performed during the course of at least a week, to provide a reliable indication of the subject's state of health.

An actigraph is a clock-like device which measures the user's long-term physical activity with respect to both quantity and daily rhythm.

The Research Scientist also investigated how external stimuli, such as the service rhythm of institutional care, or weather fluctuations, affect the behaviour of older people as measured using an actigraph. The analyses are mainly based on compiled research data logged with respect to clients of institutional care and assisted living facilities.

Merilahti observed that, in many cases, the actigraph indicators were in line with estimated functional capacity based on other methods, such as questionnaires and functional tests. Among a heterogeneous elderly population, higher functional capacity was associated with higher activity levels during the day and night. Data gathered from a unified group in institutional care showed that a lower level of functional capacity was associated with a weaker and more sporadic daily activity rhythm, and a correspondingly higher level of functional capacity with a more continuous activity rhythm.  

The thesis, "Actigraphy in evaluation and follow up of physical functioning of older adults", by Research Scientist Juho Merilahti, will be examined on 15 December at Tampere University of Technology.