241 million observations from 3.3 million women across 109 countries: The menstrual cycle had the greatest magnitude for most of the measured dimensions of mood, behaviour and vital signs

Daily, weekly, seasonal and menstrual cycles in women’s mood, behaviour and vital signs. Emma Pierson, Tim Althoff, Daniel Thomas, Paula Hillard & Jure Leskovec. Nature Human Behaviour, Feb 1 2021. https://www.nature.com/articles/s41562-020-01046-9

Abstract: Dimensions of human mood, behaviour and vital signs cycle over multiple timescales. However, it remains unclear which dimensions are most cyclical, and how daily, weekly, seasonal and menstrual cycles compare in magnitude. The menstrual cycle remains particularly understudied because, not being synchronized across the population, it will be averaged out unless menstrual cycles can be aligned before analysis. Here, we analyse 241 million observations from 3.3 million women across 109 countries, tracking 15 dimensions of mood, behaviour and vital signs using a women’s health mobile app. Out of the daily, weekly, seasonal and menstrual cycles, the menstrual cycle had the greatest magnitude for most of the measured dimensions of mood, behaviour and vital signs. Mood, vital signs and sexual behaviour vary most substantially over the course of the menstrual cycle, while sleep and exercise behaviour remain more constant. Menstrual cycle effects are directionally consistent across countries.