What do running and hormones have in common? They both influence your biological clock — right down to the molecular level.
We’re proud to share the latest scientific publication by our PhD candidate Ayano Shiba, in the Journal of Circadian Rhythms:
“Voluntary Running and Estrous Cycle Modulate ΔFOSB in the Suprachiasmatic Nucleus of the Wistar Rat”
What did the study find?
- Four weeks of voluntary running reduced expression of ΔFOSB — a marker of long-term neuronal activity — in the brain’s master clock (SCN) in both male and female rats.
- In sedentary females, ΔFOSB levels followed the estrous cycle, but this rhythmicity vanished in active runners.
- Estradiol (a key estrogen) directly reduced ΔFOSB levels, linking hormonal cycles to circadian regulation.
- Interestingly, ΔFOSB was found specifically in VIP-expressing SCN neurons, suggesting targeted molecular effects.
- Why does this matter?
ΔFOSB is involved in neuronal plasticity and behavioral adaptation. These findings deepen our understanding of how exercise and hormones fine-tune the biological clock, potentially informing new approaches to treat circadian disruptions — from shift work to jetlag.
Congratulations to Ayano and the entire research team for this important contribution to chronobiology!
Read the full paper here:
Reference:
Shiba, A., Hardonk, M. H., Foppen, E., Kool, T., la Fleur, S. E., Lucassen, P. J., Yi, C.-X., Stenvers, D. J., Mul, J. D., & Kalsbeek, A. (2025). Voluntary running and estrous cycle modulate ΔFOSB in the suprachiasmatic nucleus of the Wistar rat. Journal of Circadian Rhythms, 23(1), 7. https://doi.org/10.5334/jcr.257
