Summary
Sleep profiles of women observing Ramadan in the Gulf Cooperative Council (GCC) region were examined to model cumulative sleep deficits.
Women who used standard sleep monitoring algorithms (DSD group) showed a decrease in sleep quality index of 11%, mild dip in heart rate variability (HRV) and increased sleep movements during the Ramadan weeks.
Women users who activated Ultrahuman Ring AIR’s Ramadan Mode configuration (RMC) did not show the decline in sleep indices. This group also showed a trend of increased HRV and decreased sleep movements indicating distinct physiological responses.
Women generally had shorter naps than overall cohorts, indicating a gender-specific dependence on night-time sleep during the Ramadan period.
Background and Rationale
The practical utility of any biological research depends on its ability to address unmet needs of the target population. Women represent 49.7% of the global population however traditionally they have been underrepresented in clinical studies and preclinical research1,2. This lacuna has been recognized and increasing women representation has been a directive of laws, regulations, policies and practice guidelines resulting in 40-72% representation in studies involving new pharmaceutical entities2. However, as we steadily accumulate data for women in specific domains of human biology, we are also finding ourselves in the midst of a personalised-data gathering revolution (fueled by precision genomics and wearable technologies) for which we have little structured baseline data available.
Several surveys report a greater adoption of wearable technology among women as compared to men3,4. In terms of expectations, a peer-reviewed, mixed-methods study found that a key driver for adoption and continued use of activity trackers by women was programmability, in addition to accuracy, durability, intuitive detection and feedback5. This implies a value for customised algorithms that address specific women-related challenges and provide feedback weighted on the factors. This exacerbates challenges to develop wearables for women because there's already a lack of studies on healthy people in general, and historically, women haven't been included much in those studies.
At Ultrahuman, being aware of this extant data “double-whammy”, we are committed to find ways of parsing women-specific trends. Leveraging the real- world experimental framework provided by Ramadan to model a population-level, sleep and eating routine disruption, we developed a differential sleep scoring algorithm (Ramadan mode configuration, RMC) which has been described in previous whitepapers6,7. Here we discuss the impact of chronic sleep deprivation and influence of the RMC mode on the women subgroup to decipher preliminary trends and insights.
Methods
Being a subgroup analysis, the overall scientific design and data gathering has been described previously
here7. Briefly, Ultrahuman Ring AIR users in the Gulf Cooperative Council (GCC) region were analysed for a specific signature for the period ranging from two weeks before the onset of the holy Ramadan month (11th March 2024), through the entire month and two weeks after Eid al-Fitr (10th April 2024). Two groups were examined: a) voluntary activation of the Ramadan mode configuration in the Ultrahuman app (referred to as RMC group, N=62 and b) we also observed a different group in which individuals consistently woke up before dawn during the period of Sahoor/Sehri meal and slept after for some period. This group displayed this signature only during the four weeks of Ramadan and not in the weeks before Ramadan onset or after Eid. This group is referred to henceforth as dawn sleep deprivation (DSD) cohort, N=51. DSD Ring AIR users did not activate the Ramadan mode and hence were using unmodified sleep algorithms.
We were able to consistently track 16 women in the DSD and 7 women in the RMC subgroup respectively for this study period. Data from this set of users was used for the analyses described here. Sleep metrics such as total sleep index, average resting heart rate (HR), sleep heart rate variability (HRV), sleep start, sleep end, movements during sleep and nap duration were collected for the entire eight week period. Data analyses and aggregation is covered under terms of use of the Ultrahuman Ring AIR and application. Data analysts had no contact with any users during the entire study period and worked with de-identified data. Analysis was done in-house using Python-MATLAB modules. All populations were non-normal and we used non-parametric tests for grouped comparisons (pre- and Ramadan comparison). Due to low numbers, only descriptive statistics have been reported for the RMC women group.
Result
Dawn Sleep Deprivation (DSD) group:
Of the 51 users who were able to track for DSD mode during this study, only 16 were women. The DSD group reported true night time sleep session changes as Ramadan progressed. This group displayed a delay in sleep start time by ~100 minutes and woke up later by about ~110 minutes during Ramadan weeks. Median sleep index showed a steep, statistically significant decline in the Ramadan weeks versus the period before the onset of fasting. Post-Eid the sleep index seemed to show an upward trend indicating a slow recovery period (Figure 1a). This mirrors the signatures shown by the total DSD group in general. Primary data metrics such as resting heart rate (HR), HR minimum in the night and heart rate variability (HRV) showed a slight decrease (Figure 1b) which were not statistically significant. Sleep-time movements displayed an increase with Ramadan onset and remained high even after Ramadan ended (Figure 1c). Finally, day-time naps in this group of women did not increase appreciably during the Ramadan period (DSD Women median value= 20.1 min vs DSD whole group median value= 21.25 min) suggesting they were not compensating for poorer sleep quality any better. These metrics are consistent with whole group behaviour of the DSD cohort indicating that “women-only” analyses of night-time sleep profiles parallel mixed-cohort outputs.
Figure 1: Grouped data representation of median values for sleep index, HRV and HR and sleep movements for pre- Ramadan, Ramadan and post-Ramadan weeks for DSD users. Statistical analysis comparing pre- and Ramadan values using Wilcoxon-signed rank test. ** denotes p<0.01 N=16, error bars represent Q1-Q3 quartile limits.
Ramadan Mode Configuration (RMC) group:
A comparatively smaller set of women (N=7) in the GCC area activated the RMC sleep assessment mode. Their sleep start and end periods were delayed by ~150 minutes and ~210 minutes respectively compared to their pre-Ramadan sleep profiles, suggesting they increased their continuous sleep volume by sleeping later. This is similar to overall RMC cohort behaviour. Unlike the overall cohort (N=62) which displayed a 10% decrease in sleep index across the Ramadan weeks, the women RMC users showed no apparent change before and after the onset of Ramadan (Figure 2a). They displayed a trend of improved HRV and decreased resting HR (Figure 2b). Sleep related movements were comparable across the Ramadan and the period before, with an increase in sleep movements after the end of RMC mode activation (Figure 2c). Finally, total nap times only increased appreciably after Eid, with a median nap time in RMC women users much lesser than the mixed group (RMC Women median value= 15.6 min vs RMC whole group median value= 25.6 min). Compared to the mixed RMC cohort, women RMCs users seem to differ in having less sleep movement during Ramadan and greater increases in sleep HRV.
Figure 2: Grouped data representation of median values for sleep index, HRV and HR and sleep movements for pre- Ramadan, Ramadan and post-Ramadan weeks for RMC users. N=7, error bars represent Q1-Q3 quartile limits.
Conclusions, Limitations and Future Directions
Gender-specificity of sleep deprivation has been studied in a variety of contexts. In terms of postural stability, women seem to cope better than men when faced with sleep deprivation, however in terms of physical and cognitive agility following sleep disruption, women perform poorly8,9. Furthermore, Ramadan fasting studies usually analyse mixed gender cohorts and studies of females in this period have largely been in the context of either diabetes or pregnancy11,12. While it is known that day time napping increases during Ramadan, the impact of that on general sleep indices and well being have not been leveraged. Additionally, without any female-specific data, it is challenging to titrate wearable algorithms to provide maximum benefit to this user base.
The use of the Ultrahuman Ring AIR’s RMC mode allowed us to gather preliminary data about these two gaps. We examined two sets of women users- those who did (RMC) and did not activate the mode (DSD). DSD women recapitulated the impact on chronic sleep disruption and largely it was the same when compared the entire DSD cohort (N=51). Taken together, this implies when considering night time sleep, the responses do not differ materially for women. Perhaps daily responsibilities do not allow women to engage in long naps which likely is detrimental over the entire period of Ramadan. Instead to counteract the deficit, women may increase sleep volume as seen in the RMC case. However, sleep volume increase was also seen in the overall RMC cohort, but it was not enough to stem a decline in sleep, even when combined with more daytime napping. This indicates a specific difference in the quality of night time sleep for women and it’s importance to recovery scores. By extension it points to a possible lesser contribution of day time napping. Both these trends were picked up by the altered RMC algorithm. This phenomenon deserves in-depth investigation.
Another aspect that was intriguing was the impact of RMC mode on HRV and HR. The Cellini et al., 2016 study demonstrated that there is a nap time cardiac “calming” in healthy young women which may decrease the net recovery load on night time sleeping13. The trend of decreased HRV was also faintly observed in the mixed RMC cohort, though was not statistically significant. Taken together, it is plausible that in some cases of chronic sleep deprivation, naps take on greater salience for recovery. Equally possible is that RMC users displayed behavioural feedback to the RMC modified metrics on the Ultrahuman app which took into account their lifestyle changes. This had the potential to serve as a powerful influence on mitigating stress and promoting resilience. Finally, it is possible that improved heart metrics seen in RMC women were capturing readings from a fitter group than the general population and hence more resilient to lifestyle induced stressors. A limitation of the study were small sample sizes and the trends seen here require to be examined in a wider group of men and women across different geographies observing Ramadan or any other timed sleep disruption
By adding day time naps into the Ultrahuman Ring AIR analytical algorithm, we were able to parse out the night- and day-time coping mechanisms that individuals deploy in managing chronic stress. There are undoubtedly gender-specific mechanisms of coping at work that deserve to be examined in parallel to delineate a more cohesive picture. We hope that these exploratory indications, using a first-in-kind modified/programmed algorithmic shift, are adopted in wider, controlled studies to extend the power of remote, wearable-based monitoring.
Reach out to support@ultrahuman.com for commercial queries and science@ultrahuman.com for scientific queries.
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