Have you ever woken up five minutes before your alarm rings? This mysterious phenomenon isn't just bizarre coincidence. We are all equipped with our own internal alarm clocks and, best of all, they even have snooze buttons.
Jan Born and fellow researchers at the University of Lubeck in Germany have discovered what may be the first biological evidence for the curious ability to wake up at will. Anticipating the time you want to rise seems to trigger the release of hormones normally secreted by the body in times of stress. About an hour before you've planned to get out of bed, these secretions increase in preparation for the "stress" of waking.
In a three-night study, Born and team tucked 15 volunteers into bed at midnight the first night, and told them they would be woken at 6 a.m. on one night and 9 a.m. the other two nights.
When the volunteers knew they would be woken at six, levels of the central stress hormone adrenocorticotropin began rising around 4:30 a.m. But subjects expecting to wake at nine and rudely awakened at six experienced no such hormonal surge. Our bodies, in other words, note the time we hope to begin our day and gradually prepare us for consciousness, not unlike a snooze button.