df <- data.frame(
  id = seq(1,3,1),
  boredom = c(NA, 1, NA),
  stress = c(1, 1, 1),
  contentment = c(NA, NA, NA)
)

df2 <- data.frame(
  id = seq(1,3,1),
  boredom = c(NA, 'boredom', NA),
  stress = rep('stress', 3),
  contentment = rep(NA, 3)
)

df_updated <- df %>%
  mutate_at(vars(boredom:stress), funs(ifelse(. == 1, 'relevant column name', .)))