I'm currently working on a game that creates a window using WindowsAPI. However, at the moment the process is taking up 50% of my CPU. All I am doing is creating the window and looping using the code found below:

int WINAPI WinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance, LPSTR lpCmdLine, int nShowCmd)
{
    MSG message = {0};
    WNDCLASSEX wcl = {0};

    wcl.cbSize = sizeof(wcl);
    wcl.style = CS_OWNDC | CS_HREDRAW | CS_VREDRAW;
    wcl.lpfnWndProc = WindowProc;
    wcl.cbClsExtra = 0;
    wcl.cbWndExtra = 0;
    wcl.hInstance = hInstance = hInstance;
    wcl.hIcon = LoadIcon(0, IDI_APPLICATION);
    wcl.hCursor = LoadCursor(0, IDC_ARROW);
    wcl.hbrBackground = 0;
    wcl.lpszMenuName = 0;
    wcl.lpszClassName = "GL2WindowClass";
    wcl.hIconSm = 0;

    if (!RegisterClassEx(&wcl))
        return 0;

    hWnd = CreateAppWindow(wcl, "Application");

    if (hWnd)
    {
        if (Init())
        {
            ShowWindow(hWnd, nShowCmd);
            UpdateWindow(hWnd);         

            while (true)
            {
                while (PeekMessage(&message, 0, 0, 0, PM_REMOVE))
                {
                    if (message.message == WM_QUIT)
                        break;

                    TranslateMessage(&message);
                    DispatchMessage(&message);
                }

                if (message.message == WM_QUIT)
                    break;

               if (hasFocus)
            {
                elapsedTime = GetElapsedTimeInSeconds();
                lastEarth += elapsedTime;
                lastUpdate += elapsedTime;
                lastFrame += elapsedTime;
                lastParticle += elapsedTime;

                if(lastUpdate >= (1.0f / 100.0f))
                {
                    Update(lastUpdate);        
                    lastUpdate = 0;
                }
                if(lastFrame >= (1.0f / 60.0f))
                {
                    UpdateFrameRate(lastFrame);
                    lastFrame = 0;
                    Render();
                    SwapBuffers(hDC);
                }
                if(lastEarth >= (1.0f / 10.0f))
                {
                    UpdateEarthAnimation();
                    lastEarth = 0;
                }
                if(lastParticle >= (1.0f / 30.0f))
                {
                    particleManager->rightBooster->Update();
                    particleManager->rightBoosterSmoke->Update();
                    particleManager->leftBooster->Update();
                    particleManager->leftBoosterSmoke->Update();

                    particleManager->breakUp->Update();
                    lastParticle = 0;
                }
            }
            else
            {
                WaitMessage();
            }
            }
        }

        Cleanup();
        UnregisterClass(wcl.lpszClassName, hInstance);
    }

    return static_cast<int>(message.wParam);
}

So even when I am not drawing anything when the window has focus it still takes up 50%. I don't understand how this is taking up so much system resources.

Am I doing something wrong?

Any help would be much appreciated, thank you!