To wake a deep sleeper, find an alarm clock that engages multiple senses. Deep sleepers may be able to sleep through alarms that make a lot of noise, but engaging more than one sense makes it more likely that the sleeper wakes up.
Some alarm clocks come with devices that do more than ring loudly. They may come with attached shaking devices that fit under the pillow, and some feature monitors that blink with bright light multiple times. Combining these stimuli with a loud beeping or ringing often wakes a deep sleeper.
Heavy sleeping is a phenomenon that often fades over time. Young people spend a lot of time in the heavier, deeper sleep stages as their bodies develop and grow. With time, most people spend fewer hours each night in the deeper sleep stages.
Overall, there are four sleep stages, and three of them are considered heavy sleep. These heavier stages are characterized by slower breathing, relaxed muscles and a lower body temperature. During these stages, the body repairs damage that has occurred during waking hours, and additional tissue growth takes place. Not everyone is a heavy sleeper all the time; for most people, whether they are in a light or heavy sleep when the alarm goes off is simply a matter of timing.