diff --git a/state/sign.go b/state/sign.go
index 47edada..f2ddd8e 100644
--- a/state/sign.go
+++ b/state/sign.go
@@ -2,14 +2,21 @@ package state
 
 // SignedData returns payload bytes of the request.
 //
-// Always returns empty slice.
+// Always returns an empty slice.
 func (m NetmapRequest) SignedData() ([]byte, error) {
 	return make([]byte, 0), nil
 }
 
 // SignedData returns payload bytes of the request.
 //
-// Always returns empty slice.
+// Always returns an empty slice.
 func (m MetricsRequest) SignedData() ([]byte, error) {
 	return make([]byte, 0), nil
 }
+
+// SignedData returns payload bytes of the request.
+//
+// Always returns an empty slice.
+func (m HealthRequest) SignedData() ([]byte, error) {
+	return make([]byte, 0), nil
+}
diff --git a/state/sign_test.go b/state/sign_test.go
index 2e8da40..b5b4912 100644
--- a/state/sign_test.go
+++ b/state/sign_test.go
@@ -32,6 +32,11 @@ func TestRequestSign(t *testing.T) {
 				return new(MetricsRequest)
 			},
 		},
+		{ // HealthRequest
+			constructor: func() sigType {
+				return new(HealthRequest)
+			},
+		},
 	}
 
 	for _, item := range items {