Which habit is worse for an irregular period?

The studies

16 habits, ranked as in the video

1. 1

   Eating too much fiber

   • PMCGaskins 2009, BioCycle Study, Am J Clin Nutr 90(4):1061-9↗
2. 2

   Running long distances

   • PMCPassoni et al. Int J Sports Med 2024;45(7):543-548↗
3. 3

   Working long hours

   • sjweh.fiLawson 2015, Nurses' Health Study 3, Scand J Work Environ Health 41(2)↗
4. 4

   Painting your nails

   • PMCWang 2026, Apple Women's Health Study, Environ Int↗
5. 5

   Sleeping under six hours a night

   • PLOSLim 2016, PLOS ONE 11(11):e0167048↗
6. 6

   Dyeing your hair

   • PMCWang 2026, Apple Women's Health Study, Environ Int↗
7. 7

   Drinking tap water

   • PMCWindham 2003, Environ Health Perspect 111(7):935-41↗
8. 8

   Dry shampoo

   • PMCWang 2026, Apple Women's Health Study, Environ Int↗
9. 9

   Hardly exercising

   • PMCHahn KA et al. Clin Epidemiol 2013;5:311-9↗
10. 10

    Working night shifts

    • PubMedLawson CC et al. Epidemiology 2011;22(3):305-12↗
11. 11

    Living by a busy road

    • PubMedAssociations between Ambient Air Pollution Exposure and Menstrual Cycle Irregularity in Premenopausal Women↗
12. 12

    Wearing perfume every day

    • PMCWang 2026, Apple Women's Health Study, Environ Int↗
13. 13

    Going to bed at a different time every night

    • Gonzalez 2025, bioRxiv
    • nature.comnpj Digit Med 2019↗
14. 14

    Putting on body lotion every day

    • PubMedNishihama 2016, Reprod Toxicol 63:107-13↗
15. 15

    Working out most days

    • PMCHahn KA et al. Clin Epidemiol 2013;5:311-9↗
16. 16

    Getting into a hot car

    • PBDE serum concentrations and fecundability, PMC
    • Impact of non-occupational PBDE exposure, Sci Total Environ