Published July 1, 2025
3 views Journal article Open Access Open Access

Timing and Amplitude of Light Exposure, Not Photoperiod, Predict Blood Lipids in Arctic Residents: A Circadian Light Hypothesis.

Creators

  • 1. Department of Biology, Tyumen Medical University, 625023 Tyumen, Russia.
  • 2. Laboratory for Chronobiology and Chronomedicine, Research Institute of Biomedicine and Biomedical Technologies, Tyumen Medical University, 625023 Tyumen, Russia.
  • 3. Tyumen Cardiology Research Centre, Tomsk National Research Medical Center, Russian Academy of Science, 119991 Tyumen, Russia.
  • 4. Laboratory for Genomics, Proteomics, and Metabolomics, Research Institute of Biomedicine and Biomedical Technologies, Medical University, 625023 Tyumen, Russia.
  • 5. Laboratory of Genetics, Institute of Biology of the Karelian Science Center of the Russian Academy of Sciences, 185910 Petrozavodsk, Russia.
  • 6. Russian Academy of Sciences
  • 7. Institute of Neurosciences and Medicine, 630117 Novosibirsk, Russia.
  • 8. Department Engineering and Architecture, Lucerne University of Applied Sciences and Arts, 6048 Horw, Switzerland.
  • 9. Department of Biological & Medical Physics UNESCO, Medical University, 625023 Tyumen, Russia.
  • 10. Department of Molecular Immunology and Biotechnology, Institute of Physiology of the Federal Research Centre Komi Science Centre of the Ural Branch of the Russian Academy of Sciences, 167982 Syktyvkar, Russia.
  • 11. School of Natural Sciences, University of Tyumen, 15a Perekopskaya St., 625003 Tyumen, Russia.
  • 12. Institute of Biology/Zoology, Martin Luther University, Halle-Wittenberg, 06120 Halle, Germany.
  • 13. Department of Integrated Biology and Physiology, University of Minnesota, Minneapolis, MN 55455, USA.
  • 14. University of Minnesota

Description

In Arctic residents, blood lipids fluctuate seasonally in response to changes in light exposure (LE) patterns. This study investigates which aspects of LE (timing, dynamic range, and duration) are related to lipid profiles. We analyzed actigraphy data measuring LE and blue light exposure (BLE) along with blood determinations from 27 residents across different seasons. We assessed circadian parameters of melatonin in a subset of participants. We found that features of BLE and melatonin significantly predicted lipids: An earlier BLE acrophase was associated with higher HDL-C (β = -0.246, p = 0.013). Nighttime BLE was positively associated with TC (β = 0.290, p = 0.008) and LDL-C (β = 0.253, p = 0.025). The normalized circadian amplitude of BLE was inversely associated with the TG/HDL ratio (β = -0.384, p p = 0.007). Results remained significant after adjusting for co-factors of photoperiod duration, age, sex, and indigeneity. These findings suggest that patterns of LE (circadian light hygiene) could be a way to improve cardiovascular health.
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