diff --git a/server/model/monitor.js b/server/model/monitor.js
index 661a7f5d4..c4890339c 100644
--- a/server/model/monitor.js
+++ b/server/model/monitor.js
@@ -1432,7 +1432,7 @@ class Monitor extends BeanModel {
     async checkSlowResponseNotification(monitor, bean) {
 
         //Get recent heartbeat list with range of time
-        const afterThisDate = new Date(Date.now() - (1000 * monitor.slowResponseNotificationRange));
+        const afterThisDate = new Date(Date.now() - (1000 * (monitor.slowResponseNotificationRange + 1)));  // add 1 second otherwise we grab 0 previous beats when Time Range == Heartbeat Interval
         const previousBeats = await R.getAll(`
             SELECT * FROM heartbeat
             WHERE monitor_id = ? AND time > datetime(?) AND status = ?`,
diff --git a/src/pages/EditMonitor.vue b/src/pages/EditMonitor.vue
index c68f8cde6..820c17a8c 100644
--- a/src/pages/EditMonitor.vue
+++ b/src/pages/EditMonitor.vue
@@ -458,7 +458,7 @@
 
                             <div v-if="monitor.slowResponseNotification" class="my-3">
                                 <label for="slow-response-notification-range" class="form-label">{{ $t("slowResponseNotificationRange") }}</label>
-                                <input id="slow-response-notification-range" v-model="monitor.slowResponseNotificationRange" type="number" class="form-control" required min="0" step="1">
+                                <input id="slow-response-notification-range" v-model="monitor.slowResponseNotificationRange" type="number" class="form-control" required :min="monitor.interval" step="1">
                                 <div class="form-text">
                                     {{ $t("slowResponseNotificationRangeDescription", [monitor.slowResponseNotificationRange]) }}
                                 </div>
@@ -1198,6 +1198,14 @@ message HealthCheckResponse {
             if (this.monitor.retryInterval === oldValue) {
                 this.monitor.retryInterval = value;
             }
+            // Link interval and slowResponseNotificationRange if the are the same value
+            if (this.monitor.slowResponseNotificationRange === oldValue) {
+                this.monitor.slowResponseNotificationRange = value;
+            }
+            // But always keep slowResponseNotificationRange >= interval
+            if (this.monitor.slowResponseNotificationRange < value) {
+                this.monitor.slowResponseNotificationRange = value;
+            }
         },
 
         "monitor.timeout"(value, oldValue) {