STOCKHOLM -- The Nobel Prize for Medicine was awarded to three Americans on Monday for discoveries about the body's daily rhythms.

The laureates are Jeffrey C. Hall, Michael Rosbash and Michal W. Young. Rosbash is on the faculty at Brandeis University, Young at Rockefeller University and Hall is at the University of Maine.

The citation for the $1.1 million prize says the researchers isolated a gene that controls the normal daily biological rhythm. They "were able to peek inside our biological clock and elucidate its inner workings."

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Circadian rhythms adapt the workings of the body to different phases of the day, influencing sleep, behavior, hormone levels, body temperature and metabolism.

The winners have raised "awareness of the importance of a proper sleep hygiene" said Juleen Zierath of the Nobel academy.