Circadian phase-shifting effects of nocturnal exercise in older compared with young adults

Erin K. Baehr, Charmane I. Eastman, William Revelle, Susan H.Losee Olson, Lisa F. Wolfe, Phyllis C. Zee*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

99 Scopus citations


Exercise can phase shift the circadian rhythms of young adults if performed at the right time of day. Similar research has not been done in older adults. This study examined the circadian phase-delaying effects of a single 3-h bout of low-intensity nocturnal exercise in older (n = 8; 55-73 yr old) vs. young (n = 8; 20-32 yr old) adults. The exercise occurred at the beginning of each subject's habitual sleep time, and subjects sat in a chair in dim light during the corresponding time in the control condition. The dim-light melatonin onset (DLMO) was used as the circadian phase marker. The DLMO phase delayed more after the exercise than after the control condition. On average, the difference in phase shift between the exercise and control conditions was similar for older and young subjects, demonstrating that the phase-shifting effects of exercise on the circadian system are preserved in older adults. Therefore, exercise may potentially be a useful treatment to help adjust circadian rhythms in older and young adults.

Original languageEnglish (US)
Pages (from-to)R1542-R1550
JournalAmerican Journal of Physiology - Regulatory Integrative and Comparative Physiology
Issue number6 53-6
StatePublished - Jun 1 2003


  • Aging
  • Circadian phase angle
  • Phase shifts
  • Plasma melatonin

ASJC Scopus subject areas

  • Physiology
  • Physiology (medical)


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