diff --git a/NeedABreak/App.xaml.cs b/NeedABreak/App.xaml.cs
index 52a05dc..676fed1 100644
--- a/NeedABreak/App.xaml.cs
+++ b/NeedABreak/App.xaml.cs
@@ -41,8 +41,12 @@ public partial class App : Application
 #endif
         public static int Delay { get; set; } = 5400;      // Seconds	(put a low value here to facilitate debugging)
         private static Timer timer = Delay > 120 ? new Timer(60000) : new Timer(10000);
-        private static DateTime suspendTime;               // Time when App was suspended
-        public static bool IsSuspended { get; set; }
+        private static DateTime suspendTime;               // Time when App was suspended		
+#if DEBUG
+		private static Timer _debugTimer = new Timer(1000); 
+#endif
+
+		public static bool IsSuspended { get; set; }
 
         public static SuspensionCause SuspensionCause { get; set; }
 
@@ -77,11 +81,22 @@ public App()
             InitStartTime();            
             timer.Elapsed += Timer_Elapsed;
             timer.Start();
-            Microsoft.Win32.SystemEvents.SessionSwitch += SystemEvents_SessionSwitch;
-            Logger.Debug("App ctor end");
-        }
-
-        public static ILog Logger { get; private set; }
+            Microsoft.Win32.SystemEvents.SessionSwitch += SystemEvents_SessionSwitch;
+#if DEBUG
+			_debugTimer.Elapsed += _debugTimer_Elapsed;
+			_debugTimer.Start(); 
+#endif
+			Logger.Debug("App ctor end");
+        }
+
+#if DEBUG
+		private void _debugTimer_Elapsed(object sender, ElapsedEventArgs e)
+		{
+			System.Diagnostics.Debug.WriteLine(UserActivity.GetInactiveTime());
+		} 
+#endif
+
+		public static ILog Logger { get; private set; }
 
         private async void Timer_Elapsed(object sender, ElapsedEventArgs e)
         {
@@ -140,6 +155,8 @@ private static async Task TimesUp()
                 timer.Stop();
             }
 
+			await WaitForUserToBeIdleAsync();
+
             await Current.Dispatcher.InvokeAsync(async () =>
             {
                 var mainWindow = GetMainWindow();
@@ -148,7 +165,18 @@ await mainWindow.StartLockWorkStationAsync()
             });
         }
 
-        private static async Task TimesAlmostUp()
+		/// <summary>
+		/// Wait for user to be idle in order to avoid annoying him.
+		/// </summary>
+		/// <returns></returns>
+		private static Task WaitForUserToBeIdleAsync()
+		{
+			var userActivity = new UserActivity(TimeSpan.Zero);
+
+			return userActivity.WaitForUserToBeIdleAsync();
+		}
+
+		private static async Task TimesAlmostUp()
         {
             await Current.Dispatcher.InvokeAsync(() =>
             {
diff --git a/NeedABreak/NeedABreak.csproj b/NeedABreak/NeedABreak.csproj
index 2497f80..c6d37ba 100644
--- a/NeedABreak/NeedABreak.csproj
+++ b/NeedABreak/NeedABreak.csproj
@@ -146,6 +146,7 @@
     <Compile Include="Utils\RegistryTool.cs" />
     <Compile Include="Utils\SessionLock.cs" />
     <Compile Include="Utils\TextResourceExtension.cs" />
+    <Compile Include="Utils\UserActivity.cs" />
     <Page Include="AboutBoxWindow.xaml">
       <SubType>Designer</SubType>
       <Generator>MSBuild:Compile</Generator>
diff --git a/NeedABreak/Utils/UserActivity.cs b/NeedABreak/Utils/UserActivity.cs
new file mode 100644
index 0000000..55bfb43
--- /dev/null
+++ b/NeedABreak/Utils/UserActivity.cs
@@ -0,0 +1,66 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Runtime.InteropServices;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace NeedABreak.Utils
+{
+	public class UserActivity
+	{
+		private TimeSpan _idleTime;
+
+		/// <summary>
+		/// UserActivity constructor
+		/// </summary>
+		/// <param name="idleTime">time after which the user will be considered idle.</param>
+		public UserActivity(TimeSpan idleTime)
+		{
+			if (idleTime == TimeSpan.Zero)
+			{
+				idleTime = TimeSpan.FromSeconds(3);
+			}
+
+			_idleTime = idleTime;
+		}
+
+		[StructLayout(LayoutKind.Sequential)]
+		[System.Diagnostics.CodeAnalysis.SuppressMessage("Minor Code Smell", "S101:Types should be named in PascalCase", Justification = "<Pending>")]
+		[System.Diagnostics.CodeAnalysis.SuppressMessage("Style", "IDE1006:Naming Styles", Justification = "<Pending>")]
+		public struct LASTINPUTINFO
+		{
+			public uint cbSize;
+			public uint dwTime;
+		}
+
+		[DllImport("user32.dll")]
+		static extern bool GetLastInputInfo(ref LASTINPUTINFO plii);
+
+		public static TimeSpan GetInactiveTime()
+		{
+			LASTINPUTINFO info = new LASTINPUTINFO();
+			info.cbSize = (uint)Marshal.SizeOf(info);
+
+			if (GetLastInputInfo(ref info))
+			{
+				return TimeSpan.FromMilliseconds(Environment.TickCount - info.dwTime);
+			}
+			else
+			{
+				return TimeSpan.Zero;
+			}
+		}
+
+		public async Task WaitForUserToBeIdleAsync()
+		{
+			TimeSpan inactiveTime = GetInactiveTime();
+
+			while (inactiveTime < _idleTime)
+			{
+				await Task.Delay(1000);
+				inactiveTime = GetInactiveTime();
+			}			
+		}
+	}
+}