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Fitbit Steps Intraday

Sensor parameters description for [FITBIT_STEPS_INTRADAY]:

Key                              Description
[CONTAINER] Container where your steps intraday data is stored, depending on the data stream you are using this can be a database table, a CSV file, etc.
[EXCLUDE_SLEEP] Step data will be excluded if it was logged during sleep periods when at least one [EXCLUDE] flag is set to True. Sleep can be delimited by (1) a fixed period that repeats on every day if [TIME_BASED][EXCLUDE] is True or (2) by Fitbit summary sleep episodes if [FITBIT_BASED][EXCLUDE] is True. If both are True (3), we use all Fitbit sleep episodes as well as the time-based episodes that do not overlap with any Fitbit episodes. If [TIME_BASED][EXCLUDE] is True, make sure Fitbit sleep summary container points to a valid table or file.

RAPIDS provider

Available time segments

  • Available for all time segments

File Sequence

- data/raw/{pid}/fitbit_steps_intraday_raw.csv
- data/raw/{pid}/fitbit_steps_intraday_with_datetime.csv
- data/raw/{pid}/fitbit_sleep_summary_raw.csv (Only when [EXCLUDE_SLEEP][EXCLUDE]=True and [EXCLUDE_SLEEP][TYPE]=FITBIT_BASED)
- data/interim/{pid}/fitbit_steps_intraday_with_datetime_exclude_sleep.csv (Only when [EXCLUDE_SLEEP][EXCLUDE]=True)
- data/interim/{pid}/fitbit_steps_intraday_features/fitbit_steps_intraday_{language}_{provider_key}.csv
- data/processed/features/{pid}/fitbit_steps_intraday.csv

Parameters description for [FITBIT_STEPS_INTRADAY][PROVIDERS][RAPIDS]:

Key                              Description
[COMPUTE] Set to True to extract FITBIT_STEPS_INTRADAY features from the RAPIDS provider
[FEATURES] Features to be computed from steps intraday data, see table below
[REFERENCE_HOUR] The reference point from which firststeptime or laststeptime is to be computed, default is midnight
[THRESHOLD_ACTIVE_BOUT] Every minute with Fitbit steps data wil be labelled as sedentary if its step count is below this threshold, otherwise, active.
[THRESHOLD_DEVICE_NONWEAR_TIME] Number of consecutive minutes with zero step counts at or above which to label as a period of device non-wear time. Used only to calculate uncensoredmeancadence feature. Default is 1, which corresponds to a measure of mean non-zero walking cadence. Set to 60 for consistency with Tudor-Locke et al.’s definition. Set to 0 to disable.
[THRESHOLD_MINUTE_LEVEL_STEP_COUNT] Rows with minute-level step counts above this threshold will be excluded from feature computation. Default is 1000; set to 0 to disable.
[INCLUDE_ZERO_STEP_ROWS] Whether or not to include time segments with a 0 step count during the whole day.

Features description for [FITBIT_STEPS_INTRADAY][PROVIDERS][RAPIDS]:

Feature Units Description
sumsteps steps The total step count during a time segment.
maxsteps steps The maximum step count during a time segment.
minsteps steps The minimum step count during a time segment.
avgsteps steps The average step count during a time segment.
stdsteps steps The standard deviation of step count during a time segment.
firststeptime minutes Minutes until the first non-zero step count.
laststeptime minutes Minutes until the last non-zero step count.
countepisodesedentarybout bouts Number of sedentary bouts during a time segment.
sumdurationsedentarybout minutes Total duration of all sedentary bouts during a time segment.
maxdurationsedentarybout minutes The maximum duration of any sedentary bout during a time segment.
mindurationsedentarybout minutes The minimum duration of any sedentary bout during a time segment.
avgdurationsedentarybout minutes The average duration of sedentary bouts during a time segment.
stddurationsedentarybout minutes The standard deviation of the duration of sedentary bouts during a time segment.
countepisodeactivebout bouts Number of active bouts during a time segment.
sumdurationactivebout minutes Total duration of all active bouts during a time segment.
maxdurationactivebout minutes The maximum duration of any active bout during a time segment.
mindurationactivebout minutes The minimum duration of any active bout during a time segment.
avgdurationactivebout minutes The average duration of active bouts during a time segment.
stddurationactivebout minutes The standard deviation of the duration of active bouts during a time segment.
activetosedentarytransitionprobability unitless Active-to-sedentary transition probability (ASTP). The reciprocal of the mean active bout length during a time segment. Bounded by 0 and 1.
sumdurationactivitylessthan5minutes minutes Sum of duration of active bouts less than 5 minutes in length during a time segment.
sumdurationactivity5to105minutes minutes Sum of duration of active bouts between 5 and 10 minutes in length, inclusive, during a time segment.
sumdurationactivitygreaterthan10minutes minutes Sum of duration of active bouts more than 10 minutes in length during a time segment.
ginicoefficient unitless Measure of (absolute, not squared) variability of active bout durations normalized by the average active bout duration during a time segment. When the Gini coefficient is close to 1, it indicates that total time is accumulated via a small number of longer bouts. Conversely, when the Gini coefficient is close to 0, it indicates that all bouts contribute equally to total time.
meancadence steps/minute The average steps/minute during a time segment.
uncensoredmeancadence steps/minute The total raw steps accumulated divided by device wear time during a time segment.
peak1minutecadence steps/minute The steps/minute recorded for the highest single minute during a time segment; this is also equivalent to the maximum 1 minute cadence.
peak30minutecadence steps/minute The average steps/minute recorded for the 30 highest, but not necessarily consecutive, minutes during a time segment.
peak60minutecadence steps/minute The average steps/minute recorded for the 60 highest, but not necessarily consecutive, minutes during a time segment.
max5minutecadence steps/minute The average steps/minute of the maximum number of steps obtained over 5 continuous minutes during a time segment.
max20minutecadence steps/minute The average steps/minute of the maximum number of steps obtained over 20 continuous minutes during a time segment.
max30minutecadence steps/minute The average steps/minute of the maximum number of steps obtained over 30 continuous minutes during a time segment.
max60minutecadence steps/minute The average steps/minute of the maximum number of steps obtained over 60 continuous minutes during a time segment.
totalminutes0cadence minutes Total minutes with no movement (0 steps/minute) during a time segment; an indicator of non-ambulatory or sedentary time.
totalminutes1to19cadence minutes Total minutes with incidental movement ([1, 20) steps/minute) during a time segment.
totalminutes20to39cadence minutes Total minutes with sporadic movement ([20, 40) steps/minute) during a time segment.
totalminutes40to59cadence minutes Total minutes with purposeful steps ([40, 60) steps/minute) during a time segment.
totalminutes60to79cadence minutes Total minutes with slow walking ([60, 80) steps/minute) during a time segment.
totalminutes80to99cadence minutes Total minutes with medium walking ([80, 100) steps/minute) during a time segment.
totalminutes100to119cadence minutes Total minutes with brisk walking ([100, 120) steps/minute) during a time segment.
totalminutes120pluscadence minutes Total minutes with all faster ambulation ([120, Inf) steps/minute) during a time segment.
totalminutesabove0cadence minutes Total minutes with any movement (>0 steps/minute) during a time segment.
totalminutesabove19cadence minutes Total minutes with non-incidental movement (>19 steps/minute) during a time segment.
totalminutesabove100cadence minutes Total minutes with movement of at least moderate intensity (>100 steps/minute) during a time segment; this threshold was based on findings from ostensibly health individuals without movement impairments.

Assumptions/Observations

  1. Active and sedentary bouts. If the step count per minute is smaller than THRESHOLD_ACTIVE_BOUT (default value is 10), that minute is labelled as sedentary, otherwise, is labelled as active. Active and sedentary bouts are periods of consecutive minutes labelled as active or sedentary.
  2. Activity fragmentation features are based on the following papers: Di et al., 2017, Schrack et al., 2019, and Wanigatunga et al., 2019.
  3. Walking cadence features are based on the following review paper: Tudor-Locke et al., 2018.

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