True, natural light is better to wake up to than an alarm clock.
According to Research by the National Institute of Industrial Health in Japan, despite the popularity of using an alarm clock, waking up to a jolting noise can be bad for your heart. Waking up abruptly can cause higher blood pressure and heart rate. Besides increasing your blood pressure, an alarm can add to your stress levels by getting your adrenaline rushing.
The solution to this health-harming problem is to instead try gradually waking up to natural light. It may not be simple, but this replacement method sounds better than shrills from your alarm clock.
Here are some tips to ease you into waking up to light:
Position your bed so the sun strikes your bed appropriately.
Crack open your blinds/curtains so light can shine through your windows.
If you must rise before the sun, put your lights on a timer.
Wake up at the same time everyday to make your body accustomed to your new sleep schedule.
Source: http://dormiamattress.wordpress.com/2011/06/20/how-to-start-your-mornings-great/ http://www.helpguide.org/life/sleep_tips.htm http://www.dailymail.co.uk/health/article-412283/How-alarming-Your-bedside-clock-bad-health.html