diff --git a/pages/timer/timer.js b/pages/timer/timer.js
index 7edbd32..1ed775a 100644
--- a/pages/timer/timer.js
+++ b/pages/timer/timer.js
@@ -66,8 +66,11 @@ Page({
 
     // Reset reminder state
     this._halfwaySignaled = false
+    this._last30Signaled = false
+    this._last10Signaled = false
     this._lastMinuteAt = 0
     this._lastCountdown = 0
+    this._saving = false
 
     this._timer = new Timer({
       onTick: (tick) => {
@@ -188,8 +191,14 @@ Page({
   },
 
   finishTraining() {
+    // Guard against double-tap: stop button is still visible during the
+    // 1.5s navigateBack delay, so a second tap would create a duplicate.
+    if (this._saving) return
+    this._saving = true
+
     const elapsed = this._timer.stop()
     if (elapsed < 3) {
+      this._saving = false
       wx.showToast({ title: '训练时间太短', icon: 'none', duration: 1500 })
       setTimeout(() => { wx.navigateBack() }, 1500)
       return