diff --git a/app/api/v1/schema/record.py b/app/api/v1/schema/record.py
index 80e1813..f8634f5 100644
--- a/app/api/v1/schema/record.py
+++ b/app/api/v1/schema/record.py
@@ -33,7 +33,7 @@ class BodyRecordChartIn(Schema):
 class BodyRecordChartNestedOut(Schema):
     weights = fields.List(fields.Float())
     bmis = fields.List(fields.Float())
-    x_axis = fields.List(fields.Float())
+    x_axis = fields.List(fields.String())
 
 
 class BodyRecordChartOut(Schema):