| Activity |
| Accelerometer |
Activity level; step count; sedentary time; speed |
Physical activity; energy expenditure; sleep |
| Pedometer |
Steps count |
Physical activity |
| Global positioning system (GPS) |
Distance travelled; location |
Function; social interaction; participation |
| Movement/posture/muscle activity |
| Magnetic (magnetometer), angular rate (gyroscope) and gravity (accelerometer) sensors |
Orientation relative to earth |
Joint angle/posture or relative angle/posture when 2 sensors are incorporated |
| Strain sensors (e.g., fibre optic; inductance) |
Length change |
Spine—movement/posture; chest—breathing |
| Goniometer |
Angle |
Joint angular motion |
| Pressure sensor |
Force |
Shoe—foot contact; ground reaction forces; inverse dynamics; chest—breathing |
| Electromyography (single channel and grid) |
Muscle activity |
Contraction/relaxation of muscle |
| Physiological |
| Photoplethysmography (PPG) |
Heart rate; heart rate variability; heart rate recovery; oxygen saturation; sleep stages; cardiac output |
Exercise tolerance; stress |
| Electrocardiography (ECG) |
Heart rate; heart rate variability |
Exercise tolerance; stress |
| Electroencephalography (EEG) |
Brain activity |
Sleep; sleep architecture; attention |
| Near Infrared spectroscopy |
Muscle oxygenation; Oxy-, deoxy- and total haemoglobin; cerebral oxygenation |
Oxygen saturation in muscle |
| Biochemical sensors (e.g., epidermal; sweat; transdermal) |
Cortisol; pH; electrolytes; glucose; lactate |
Stress; nutrition; fatigue |
| Skin conductance |
|
|
| Temperature |
Body temperature |
Temperature; heat stress |
| Other measures |
| Video (smart glasses) |
Activity; social interaction |
|
| Sound |
Language analysis; ambient sound |
Social interaction; environmental context; social ambience measures |
| Light |
Ambient light |
Environmental context |
