diff --git a/lib/appsignal/heartbeat.rb b/lib/appsignal/heartbeat.rb
index ef8016ba..01e95722 100644
--- a/lib/appsignal/heartbeat.rb
+++ b/lib/appsignal/heartbeat.rb
@@ -37,10 +37,15 @@ def event(kind)
     end
 
     def transmit_event(kind)
+      unless Appsignal.active?
+        Appsignal.internal_logger.debug("AppSignal not active, not transmitting heartbeat event")
+        return
+      end
+
       response = self.class.transmitter.transmit(event(kind))
 
       if response.code.to_i >= 200 && response.code.to_i < 300
-        Appsignal.internal_logger.trace("Transmitted heartbeat `#{name}` #{kind} event")
+        Appsignal.internal_logger.trace("Transmitted heartbeat `#{name}` (#{id}) #{kind} event")
       else
         Appsignal.internal_logger.error(
           "Failed to transmit heartbeat event: status code was #{response.code}"
diff --git a/spec/lib/appsignal/heartbeat_spec.rb b/spec/lib/appsignal/heartbeat_spec.rb
index 4ad2eb2c..48f20c0d 100644
--- a/spec/lib/appsignal/heartbeat_spec.rb
+++ b/spec/lib/appsignal/heartbeat_spec.rb
@@ -4,15 +4,26 @@
   let(:transmitter) { Appsignal::Transmitter.new("http://heartbeats/", config) }
 
   before(:each) do
+    allow(Appsignal).to receive(:active?).and_return(true)
     config.logger = Logger.new(StringIO.new)
     allow(Appsignal::Heartbeat).to receive(:transmitter).and_return(transmitter)
   end
 
+  describe "when Appsignal is not active" do
+    it "should not transmit any events" do
+      allow(Appsignal).to receive(:active?).and_return(false)
+      expect(transmitter).not_to receive(:transmit)
+
+      heartbeat.start
+      heartbeat.finish
+    end
+  end
+
   describe "#start" do
     it "should send a heartbeat start" do
       expect(transmitter).to receive(:transmit).with(hash_including(
         :name => "heartbeat-name",
-        :kind => "Start"
+        :kind => "start"
       )).and_return(nil)
 
       heartbeat.start
@@ -23,7 +34,7 @@
     it "should send a heartbeat finish" do
       expect(transmitter).to receive(:transmit).with(hash_including(
         :name => "heartbeat-name",
-        :kind => "Finish"
+        :kind => "finish"
       )).and_return(nil)
 
       heartbeat.finish
@@ -34,12 +45,12 @@
     describe "when a block is given" do
       it "should send a heartbeat start and finish and return the block output" do
         expect(transmitter).to receive(:transmit).with(hash_including(
-          :kind => "Start",
+          :kind => "start",
           :name => "heartbeat-with-block"
         )).and_return(nil)
 
         expect(transmitter).to receive(:transmit).with(hash_including(
-          :kind => "Finish",
+          :kind => "finish",
           :name => "heartbeat-with-block"
         )).and_return(nil)
 
@@ -67,7 +78,7 @@
     describe "when no block is given" do
       it "should only send a heartbeat finish event" do
         expect(transmitter).to receive(:transmit).with(hash_including(
-          :kind => "Finish",
+          :kind => "finish",
           :name => "heartbeat-without-block"
         )).and_return(nil)