diff --git a/NEWS.md b/NEWS.md
index 6872fb1..263ee28 100644
--- a/NEWS.md
+++ b/NEWS.md
@@ -1,7 +1,7 @@
 spiro (development version)
 ===========================
 
-
+* Fix bug in Cosmed import leading to failure in rare cases
 
 spiro 0.2.3 (2025-02-18)
 ===========================
diff --git a/R/spiro_get.R b/R/spiro_get.R
index 90f6371..90a9604 100644
--- a/R/spiro_get.R
+++ b/R/spiro_get.R
@@ -245,7 +245,8 @@ spiro_get_cosmed <- function(file) {
     bodymass = as.numeric(
       get_meta(
         tbl,
-        c("Weight (Kg):", "Weight (Kg)", "Gewicht (Kg):", "Gewicht (Kg)")
+        c("Weight (Kg):", "Weight (Kg)", "Gewicht (Kg):", "Gewicht (Kg)",
+          "Weight (kg):", "Weight (kg)", "Gewicht (kg):", "Gewicht (kg)")
       )
     )
   )
@@ -308,10 +309,15 @@ spiro_get_cosmed <- function(file) {
   # rare special case if body mass has been deleted from meta data. Recalculates
   # body mass based on relative oxygen uptake present in raw data
   if (is.na(info$bodymass)) {
-    info$bodymass <- round(
-      # used first data value to recalculate body mass
-      as.numeric(data$VO2[[1]]) / as.numeric(data$`VO2/Kg`[[1]]), 1
-    )
+    if (any(colnames(data) == "VO2/Kg")) {
+      info$bodymass <- round(
+        as.numeric(data$VO2[[1]]) / as.numeric(data$`VO2/Kg`[[1]]), 1
+      )
+    } else if (any(colnames(data) == "VO2/kg")) {
+      info$bodymass <- round(
+        as.numeric(data$VO2[[1]]) / as.numeric(data$`VO2/kg`[[1]]), 1
+      )
+    }
   }
 
   attr(df, "info") <- info # write meta data
diff --git a/tests/testthat/testdata/cosmed.xlsx b/tests/testthat/testdata/cosmed.xlsx
index ef71a4b..cb399d9 100644
Binary files a/tests/testthat/testdata/cosmed.xlsx and b/tests/testthat/testdata/cosmed.xlsx differ