diff --git a/tracker/api.py b/tracker/api.py
index ff29d4f..9ca7602 100644
--- a/tracker/api.py
+++ b/tracker/api.py
@@ -330,7 +330,7 @@ def list_pulse(request: HttpRequest, days: int = 90):
 @router.post("/pulse", response=PulseOut)
 def record_pulse(request: HttpRequest, payload: PulseIn):
     """One reading per day: posting twice for the same day overwrites it."""
-    if not 20 <= payload.bpm <= 400:
+    if not 10 <= payload.bpm <= 400:
         raise HttpError(422, "A pulse of that value is not plausible for a cat.")
 
     day = payload.date or timezone.localdate()