diff --git a/stomp/listener.py b/stomp/listener.py
index f063f3f6..81d92300 100644
--- a/stomp/listener.py
+++ b/stomp/listener.py
@@ -217,13 +217,16 @@ def on_heartbeat(self):
 
     def on_send(self, frame):
         """
-        Add the heartbeat header to the frame when connecting.
+        Add the heartbeat header to the frame when connecting, and bump
+        next outbound heartbeat timestamp.
 
         :param Frame frame: the Frame object
         """
         if frame.cmd == CMD_CONNECT or frame.cmd == CMD_STOMP:
             if self.heartbeats != (0, 0):
                 frame.headers[HDR_HEARTBEAT] = '%s,%s' % self.heartbeats
+        if self.next_outbound_heartbeat is not None:
+            self.next_outbound_heartbeat = monotonic() + self.send_sleep
 
     def __update_heartbeat(self):
         # Honour any grace that has been already included
@@ -259,8 +262,6 @@ def __heartbeat_loop(self):
             now = monotonic()
 
             if self.send_sleep != 0 and now > self.next_outbound_heartbeat:
-                self.next_outbound_heartbeat = now + self.send_sleep
-
                 log.debug("Sending a heartbeat message at %s", now)
                 try:
                     self.transport.transmit(utils.Frame(None, {}, None))
diff --git a/stomp/transport.py b/stomp/transport.py
index a94f1454..30bfa1a7 100644
--- a/stomp/transport.py
+++ b/stomp/transport.py
@@ -254,9 +254,9 @@ def transmit(self, frame):
         packed_frame = pack(lines)
 
         if log.isEnabledFor(logging.DEBUG):
-            log.debug("Sending frame %s", lines)
+            log.debug("Sending frame: %s", lines)
         else:
-            log.info("Sending frame cmd=%r headers=%r", frame.cmd, frame.headers)
+            log.info("Sending frame: %r, headers=%r", frame.cmd or "heartbeat", frame.headers)
 
         self.send(encode(packed_frame))