Detect ventilatory thresholds from incremental exercise data

VT1 is estimated by V-slope breakpoint regression of VCO2 on VO2. VT2 is estimated above VT1 from the breakpoint of VE on VCO2.

Usage

ventilatoryThreshold(
  vo2,
  vco2 = NULL,
  ve = NULL,
  time = NULL,
  average_n = 1L,
  min_segment = 3L
)

Arguments

vo2

Numeric VO2 vector, or a data frame containing vo2, vco2, and ve.

vco2, ve

Numeric vectors matching vo2 when it is not a data frame.

time

Optional time vector. For data-frame input, an existing time column is used unless this argument is supplied.

average_n

Positive integer number of ordered samples per block mean.

min_segment

Minimum number of observations fitted on each side of a breakpoint.

Value

A ventilatory_threshold object with VT1, VT2, and the data actually fitted.

References

Beaver WL, Wasserman K, Whipp BJ (1986). A new method for detecting anaerobic threshold by gas exchange. Journal of Applied Physiology, 60:2020-2027. doi:10.1152/jappl.1986.60.6.2020

Examples

vo2 <- seq(1, 3, by = 0.05)
vco2 <- ifelse(vo2 <= 2, 0.9 * vo2, 1.8 + 1.3 * (vo2 - 2))
ventilatoryThreshold(vo2, vco2, ve = 25 * vco2)
#> <ventilatory_threshold> method=v-slope
#>   VT1: VO2 2, VCO2 1.8, VE 45 (slopes 0.9 -> 1.3)
#>   VT2: not detected