Researchers at Clue conducted an internal pilot study using wearable sensor technology (specifically, the FitBit Charge HR). The research found that resting heart rates (RHRs) show distinct values for the four phases of menstrual cycle. This opens exciting possibilities for passive consumer grade sensors to be used in future scientific studies.
This current study collected data on resting heart rate, ovulation, menstrual cycle length and period duration in six healthy individuals with regular cycles (25–40 years old) for up to twelve menstrual cycles. It also tracked negative controls — female participants on hormonal birth control and a male participant.
This study found a rise in RHR after the ovulation, similar to already known body basal temperature (BBT) bump. This is not a completely new finding, as the other researchers have reported it before, however the novelty is that this has never been done before with the help of wearable sensor technology that’s readily available to consumers.
RHR was significantly higher in both ovulatory and luteal phase (the second part of the cycle) when compared to menstruation and the follicular phase (the first part of the cycle).
Fun fact: Dr. Vedrana Högqvist Tabor, our Director of Scientific Research, determined Lisa Kennelly, our Director of Marketing, was pregnant thanks to her FitBit heart rate data.
“Wearable sensor technology is very powerful, as it can make us aware of the minute, but significant changes in our bodies. Lisa and I were able to predict she is pregnant when she was only 4 weeks along, only by looking at the heart rate measurements. Of course, she missed her period too. This is a wonderful beginning of technology enabling us to have a better overview of our health.” -Dr. Vedrana Högqvist Tabor
These findings were presented July 3–6 at the yearly ESHRE meeting (European Society of Human Reproduction and Embryology) by Clue’s Dr. Tabor in Helsinki, Finland. The poster was called “Resting heart rate changes during the menstrual cycle.”