Circadian oscillations in rodents: a systematic increase of their frequency with age.

@article{Pittendrigh1974CircadianOI,
  title={Circadian oscillations in rodents: a systematic increase of their frequency with age.},
  author={C S Pittendrigh and Serge Daan},
  journal={Science},
  year={1974},
  volume={186 4163},
  pages={548-50}
}
The circadian activity rhythms of golden hamsters and two species of deermouse, when released from a light-dark cycle of 12 hours light and 12 hours of darkness into constant darkness, had progressively shorter periods as the animals became older. A possible bearing of this fact on the aging process is briefly outlined.