diff --git a/main.cpp b/main.cpp
index 4b7bbda..470138d 100644
--- a/main.cpp
+++ b/main.cpp
@@ -778,10 +778,14 @@ class Framework {
         if (heartRateController.State() == Pinetime::Controllers::HeartRateController::States::Stopped) {
           heartRateController.Start();
         } else if (heartRateController.State() == Pinetime::Controllers::HeartRateController::States::NotEnoughData) {
-          heartRateController.Update(Pinetime::Controllers::HeartRateController::States::Running, 10);
+          heartRateController.Update(Pinetime::Controllers::HeartRateController::States::Running, std::make_optional<uint8_t>(10));
         } else {
-          uint8_t heartrate = heartRateController.HeartRate();
-          heartRateController.Update(Pinetime::Controllers::HeartRateController::States::Running, heartrate + 10);
+          auto heartrate = heartRateController.HeartRate();
+          if (heartrate.has_value()) {
+            heartRateController.Update(Pinetime::Controllers::HeartRateController::States::Running, std::make_optional<uint8_t>(heartrate.value() + 10));
+          } else {
+            heartRateController.Update(Pinetime::Controllers::HeartRateController::States::Running, std::make_optional<uint8_t>(10));
+          }
         }
       } else if (key == 'H') {
         heartRateController.Stop();
diff --git a/sim/components/heartrate/HeartRateController.cpp b/sim/components/heartrate/HeartRateController.cpp
index c7d0397..edb059c 100644
--- a/sim/components/heartrate/HeartRateController.cpp
+++ b/sim/components/heartrate/HeartRateController.cpp
@@ -1,10 +1,11 @@
 #include "components/heartrate/HeartRateController.h"
 #include <heartratetask/HeartRateTask.h>
 #include "systemtask/SystemTask.h"
+#include <optional>
 
 using namespace Pinetime::Controllers;
 
-void HeartRateController::Update(HeartRateController::States newState, uint8_t heartRate) {
+void HeartRateController::Update(HeartRateController::States newState, std::optional<uint8_t> heartRate) {
   this->state = newState;
   if (this->heartRate != heartRate) {
     this->heartRate = heartRate;
diff --git a/sim/components/heartrate/HeartRateController.h b/sim/components/heartrate/HeartRateController.h
index 89feefc..4736a26 100644
--- a/sim/components/heartrate/HeartRateController.h
+++ b/sim/components/heartrate/HeartRateController.h
@@ -1,6 +1,7 @@
 #pragma once
 
 #include <cstdint>
+#include <optional>
 //#include <components/ble/HeartRateService.h>
 
 namespace Pinetime {
@@ -18,13 +19,13 @@ namespace Pinetime {
       HeartRateController() = default;
       void Start();
       void Stop();
-      void Update(States newState, uint8_t heartRate);
+      void Update(States newState, std::optional<uint8_t> heartRate);
 
       void SetHeartRateTask(Applications::HeartRateTask* task);
       States State() const {
         return state;
       }
-      uint8_t HeartRate() const {
+      std::optional<uint8_t> HeartRate() const {
         return heartRate;
       }
 
@@ -33,7 +34,7 @@ namespace Pinetime {
     private:
       Applications::HeartRateTask* task = nullptr;
       States state = States::Stopped;
-      uint8_t heartRate = 0;
+      std::optional<uint8_t> heartRate = std::nullopt;
       //Pinetime::Controllers::HeartRateService* service = nullptr;
     };
   }