R/compute_bmr.R

In activAnalyzer: A 'Shiny' App to Analyze Accelerometer-Measured Daily Physical Behavior Data

#' Compute Basal Metabolic Rate (BMR)
#' 
#' This function computes Basal Metabolic Rate in kcal/d using a Henry et al. 
#'     (2005; doi: 10.1079/PHN2005801) equation. This function is wrapped within 
#'     the \code{\link{mark_intensity}} and \code{\link{recap_by_day}} functions.
#'
#' @param age A numeric value in yr.
#' @param weight A numeric value in kg.
#' @param sex A character value.
#'
#' @return A numeric value.
#' @export
#'
#' @examples
#' compute_bmr(age = 32, sex = "male", weight = 67)
#' 
compute_bmr <- function(age = 40, sex = c("male", "female", "intersex", "undefined", "prefer not to say"), weight = 70) {
  
sex <- match.arg(sex)
  
  if(is.na(age)) { bmr <- NA } else {
    
    
    # BMR using sex and weight only (Henry, 2005; doi: 10.1079/PHN2005801)
    
    if(age <3   && sex == "male"           )  { bmr <- 61.0 * weight - 33.7 }
    if(age >=3  && age <10 && sex == "male")   { bmr <- 23.3 * weight + 514  }
    if(age >=10 && age <18 && sex == "male")   { bmr <- 18.4 * weight + 581  }
    if(age >=18 && age <30 && sex == "male")   { bmr <- 16.0 * weight + 545  }
    if(age >=30 && age <60 && sex == "male")   { bmr <- 14.2 * weight + 593  }
    if(age >=60 && age <70 && sex == "male")   { bmr <- 13.0 * weight + 567  }
    if(age >=70 && sex == "male"           )   { bmr <- 13.7 * weight + 481  }
    
    if(age <3   && sex == "female"                                                               ) { bmr <- 58.9 * weight - 23.1 }
    if(age >=3  && age <10 && (sex == "female" | sex == "undefined" | sex == "prefer not to say")) { bmr <- 20.1 * weight + 507  }
    if(age >=10 && age <18 && (sex == "female" | sex == "undefined" | sex == "prefer not to say")) { bmr <- 11.1 * weight + 761  }
    if(age >=18 && age <30 && (sex == "female" | sex == "undefined" | sex == "prefer not to say")) { bmr <- 13.1 * weight + 558  }
    if(age >=30 && age <60 && (sex == "female" | sex == "undefined" | sex == "prefer not to say")) { bmr <- 9.74 * weight + 694  }
    if(age >=60 && age <70 && (sex == "female" | sex == "undefined" | sex == "prefer not to say")) { bmr <- 10.2 * weight + 572  }
    if(age >=70 && (sex == "female" | sex == "undefined" | sex == "prefer not to say")           ) { bmr <- 10.0 * weight + 577  }
    
    if(age <3   && sex == "intersex"           )  { bmr <- ((61.0 * weight - 33.7) + (58.9 * weight - 23.1)) / 2 }
    if(age >=3  && age <10 && sex == "intersex")  { bmr <- ((23.3 * weight + 514) + (20.1 * weight + 507)) / 2   }
    if(age >=10 && age <18 && sex == "intersex")  { bmr <- ((18.4 * weight + 581) + (11.1 * weight + 761)) / 2   }
    if(age >=18 && age <30 && sex == "intersex")  { bmr <- ((16.0 * weight + 545) + (13.1 * weight + 558)) / 2   }
    if(age >=30 && age <60 && sex == "intersex")  { bmr <- ((14.2  * weight + 593) + (9.74 * weight + 694)) / 2  }
    if(age >=60 && age <70 && sex == "intersex")  { bmr <- ((13.0 * weight + 567) + (10.2 * weight +  572)) / 2  }
    if(age >=70 && sex == "intersex"           )  { bmr <- ((13.7 * weight + 481) + (10.0 * weight + 577)) / 2   }
    
  }
  # BMR using sex, weight and height (Henry, 2005; doi: 10.1079/PHN2005801)
  
  #bmr_bis <-
  #  ifelse(age <3 & sex == "male", 28.2 * weight + 859 * height - 371,
  #         ifelse(age >=3 & age <10 & sex == "male", 15.1 * weight + 74.2 * height + 306,
  #                ifelse(age >=10 & age <18 & sex == "male", 15.6 * weight + 266 * height + 299,
  #                       ifelse(age >=18 & age <30 & sex == "male", 14.4 * weight + 313 * height + 113,
  #                              ifelse(age >=30 & age <60 & sex == "male", 11.4 * weight + 541 * height - 137,
  #                                     ifelse(age >=60 & sex == "male", 11.4 * weight + 541 * height - 256,
  #                                            
  #                                            ifelse(age <3 & sex == "female", 30.4 * weight + 703 * height - 287,
  #                                                   ifelse(age >=3 & age <10 & (sex == "female" | sex == "undefined"), 15.9 * weight + 210 * height + 349,
  #                                                          ifelse(age >=10 & age <18 & (sex == "female" | sex == "undefined"), 9.40 * weight + 249 * height + 462,
  #                                                                 ifelse(age >=18 & age <30 & (sex == "female" | sex == "undefined"), 10.4 * weight + 615 * height - 282,
  #                                                                        ifelse(age >=30 & age <60 & (sex == "female" | sex == "undefined"), 8.18 * weight + 502 * height - 11.6,
  #                                                                               ifelse(age >=60 & (sex == "female" | sex == "undefined"), 8.52 * weight + 421 * height + 10.7))))))))))))
  
  message(paste0("You have computed BMR using the following inputs: 
    age = " , age, "
    weight = ", weight, "
    sex = ", sex))
  
return(bmr)
  
}