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Return maximum values from cardiopulmonary exercise tests

Source: R/spiro_max.R
spiro_max.Rd

spiro_max() returns a data.frame with the maximum gas exchange parameters of an exercise test.

Usage

spiro_max(data, smooth = 30, hr_smooth = FALSE)

Arguments

data

A data.frame of the class spiro containing the gas exchange data. Usually the output of a spiro call.

smooth

Parameter giving the filter methods for smoothing the data. Default is 30 for a 30-second moving average. "20b" will apply a 20-breath averaging for example. See spiro_smooth for further details and filter methods (e.g. Butterworth filters).

hr_smooth

A logical, whether smoothing should also apply to heart rate data. Default is FALSE, which means that the absolute maximum heart rate value is taken without smoothing.

Value

A data.frame with the maximum parameter values of the data.

Details

Before calculating the maximum values, the raw data is smoothed. Default smoothing method is a 30-second rolling average. See the smooth argument in spiro_smooth for more options, such as breath-based averages or digital filtering.

Parameters calculated are the maxima of oxygen uptake (absolute and relative), carbon dioxide output, minute ventilation, respiratory exchange ratio (RER), and heart rate. The maximum values are defined as the highest single data values after the smoothing.

For the maximum RER a different algorithm is used, as the RER during and after rest may exceed the peak value during exercise. Therefore only values during the last ten percent of the exercise time are considered for the RERmax determination. The RERmax calculation works best for data from tests without rest intervals (e.g., ramp tests) and with attached load protocol data.

Examples

# Import and process example data sets
gxt_data <- spiro(file = spiro_example("zan_gxt"))

spiro_max(gxt_data)
#>       VO2    VCO2     VE VO2_rel  RER HR
#> 1 4732.28 4640.75 129.62    71.7 0.99 NA

# Use an averaging over a time interval of 15 seconds
spiro_max(gxt_data, smooth = 15)
#>      VO2    VCO2     VE VO2_rel  RER HR
#> 1 4774.6 4681.83 130.56   72.34 1.02 NA

# Use an averaging over an interval of 15 breaths
spiro_max(gxt_data, smooth = "15b")
#>       VO2   VCO2     VE VO2_rel  RER HR
#> 1 4774.13 4674.8 130.79   72.34 1.02 NA