diff --git a/r2/r2/lib/promote.py b/r2/r2/lib/promote.py
index d88eda02b3..8806dba033 100644
--- a/r2/r2/lib/promote.py
+++ b/r2/r2/lib/promote.py
@@ -64,7 +64,8 @@ def _mark_promos_updated():
 
 
 def health_check():
-    return NamedGlobals.get(PROMO_HEALTH_KEY, default=0)
+    """Calculate the number of seconds since promotions were last updated"""
+    return time.time() - int(NamedGlobals.get(PROMO_HEALTH_KEY, default=0))
 
 
 @memoize("get_promote_srid")