Objective monitoring of physical activity using motion sensors and heart rate.

Although neither motion sensors nor heart rate are perfect markers of physical activity, they certainly eliminate subjectivity of obtaining physical activity information. The objective method of choice depends on how the measurement will be used. For example, if walking behavior is the desired outcome, then a pedometer may be sufficient. If patterns and intensity of activity over longer periods of times such as a week or longer are needed, then an accelerometer with large memory capacity should be selected. In the future, efforts should be directed towards developing an objective motion sensor as inexpensive as a pedometer but with the data acquisition capabilities of the CSA or Tritrac accelerometer. Providing simultaneous heart rate with motion is also recommended to further verify that elevated heart rate does in fact represent a physical activity response. As the cost of the electronic components continues to decrease, these activity monitor configurations may become possible.