Estimating the Perception of Physical Fatigue Among Older Adults Using Mobile Phones

Fatigue is one of the symptoms associated with frailty among older adults, a syndrome that signals a progressive deterioration of physical and mental capacity. It is commonly measured by clinical studies, physical tests, or questionnaires, involving effort some people can’t attain. We describe a method to assess the fatigue a person experiences while walking by measuring their demand for oxygen and heart rate. The approach makes use of the accelerometer in the mobile phone, thus allowing for continuous fatigue assessment under naturalistic conditions. Results show a margin of error of less than 5 heart beats per minute and no significant difference between heart rate’s base-line fatigue classification and predicted fatigue classification; which compares favourably with current approaches. The method can be used to monitor health conditions among the frail.