Personalized Baselines in Vital Signs: Insights from Wearable-Derived Sleep Data in Healthy Adults

Author(s): Nima Sarani, Raymond Che, Bradley S Jackson, Cameron Hanson, Sarah Selby, Diti Ronvelia, Michelle Wilson, Kapil P. Gude, Rohan L Fernandes

Population-based thresholds for vital signs, such as defining heart rate above 100 bpm as tachycardia, fail to capture individual physiological variability. Advances in wearable technology have enabled continuous, personalized monitoring of vital signs, offering the possibility of individualized baselines for health assessment. In this study, we examined sleep-derived vital sign data from eight healthy adults who wore Apple Watch devices across multiple nights. Data collected included respiratory rate (RR), heart rate (HR), oxygen saturation (SpO?), heart rate variability (HRV, RMSSD), and skin/wrist temperature (SWT). Participants exhibited unique and stable baselines for each vital sign, underscoring the importance of personalized thresholds in health monitoring. These results suggest that deviations from individual baselines could serve as sensitive markers for early detection of physiological changes, surpassing the limitations of population norms.