Core Viewpoint - The accuracy of stress monitoring by smartwatches and apps is questioned, as many users report discrepancies between their perceived stress levels and the readings from these devices [4][12][55]. Group 1: User Experiences - Many users have shared experiences where their smartwatches inaccurately indicated high stress levels during relaxed situations or low stress during stressful times [6][11][14]. - The inconsistency in stress readings has led to skepticism about the reliability of these devices [4][12]. Group 2: Measurement Methodology - Smartwatches typically measure stress through heart rate variability (HRV), which reflects the variation in time between heartbeats rather than just heart rate [17][33]. - A healthy heart rate shows variability, while a low HRV indicates stress, but this can be influenced by both psychological and physiological factors [29][36]. Group 3: Physiological Influences - Factors such as caffeine intake, exercise, and alcohol consumption can also lower HRV, leading to misleading stress readings from smartwatches [37][40][44]. - Emotional states, such as excitement or anxiety, can similarly affect HRV, complicating the interpretation of stress levels [45][46]. Group 4: Research Findings - A study involving 781 students found that the stress levels reported by smartwatches did not align with the participants' self-reported stress, indicating a disconnect between device readings and actual psychological states [49][54]. - The study highlights that wearable devices measure a broad physiological load rather than specific psychological stress [57]. Group 5: Industry Insights - There is a lack of clarity in how manufacturers communicate the capabilities of their devices, often leading to misconceptions about their ability to measure psychological stress accurately [61][64]. - While some developers provide accurate explanations of HRV, others may mislead users into believing their devices can precisely monitor psychological stress [62][66]. Group 6: Practical Implications - Understanding the limitations of HRV measurements can help users appreciate the broader context of their physiological state rather than relying solely on these readings for psychological insights [70][71]. - Smartwatches and apps can still serve a purpose in providing general health insights, but they should not be solely relied upon for accurate psychological stress assessment [68][73].