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Summarise free-living physical behaviour over one or more days

Source: R/freeliving-summary.R
summarizeFreeLiving.Rd

The umbrella summary: from multi-day per-epoch ENMO (plus optional timestamps and a wear mask) it computes, per valid day and averaged across valid days, the physical-behaviour metrics that free-living accelerometry studies report – intensity time-use (sedentary / light / MVPA), activity volume, the Rowlands intensity gradient and MX metrics, activity fragmentation, the diurnal profile and WHO guideline attainment. Only days with enough wear time are counted as valid; non-wear epochs are excluded from the intensity tallies.

Usage

summarizeFreeLiving(
  enmo,
  epoch_sec,
  timestamps = NULL,
  wear = NULL,
  enmo_unit = c("mg", "g"),
  thresholds = paIntensityThresholds(),
  valid_wear_hours = 10,
  steps_per_day = NULL,
  guideline_mvpa_min = 150
)

Arguments

enmo

Per-epoch ENMO (see computeENMO()).

epoch_sec

Epoch length in seconds.

timestamps

Optional per-epoch POSIXct timestamps; when supplied, days are split on the calendar date and the diurnal profile is computed.

wear

Optional per-epoch logical wear mask (TRUE = worn). Default: all worn.

enmo_unit

Unit of enmo: "mg" (default) or "g".

thresholds

Intensity cut-points in mg (see paIntensityThresholds()).

valid_wear_hours

Minimum wear hours for a day to be valid (default 10).

steps_per_day

Optional numeric vector of steps for each day (in day order) folded into the per-day table and averages.

guideline_mvpa_min

Weekly MVPA-equivalent minutes for guideline attainment (default 150; WHO 2020, counting vigorous double).

Value

A freeliving_summary object: by_day (per-day data frame), aggregate (means over valid days plus guideline attainment), diurnal (or NULL), n_valid_days and settings.

References

Rowlands (2018); Chastin (2010); WHO (2020).

See also

intensityGradient(), mxMetrics(), activityFragmentation(), freeLivingICF()

Examples

set.seed(1)
# one day, 30 s epochs: mostly sedentary with an active hour
enmo <- c(rep(5, 2 * 60 * 10), rep(120, 2 * 60), rep(5, 2 * 60 * 12))
s <- summarizeFreeLiving(enmo, epoch_sec = 30, valid_wear_hours = 0)
s$aggregate$mvpa_min
#> [1] 60