It’s not just about the steps or heart rates anymore. Wearable technology companies are moving beyond these metrics to a more complex objective, tracking your mood and emotional stress. The shift comes as demand for mental health support continues to grow in many countries.
Consumer wearables, positioned as wellness tools rather than medical devices, offer a way to monitor day-to-day stress at scale, even if their insights remain indirect.
Monitoring Physiological Signals
Unlike heart rate or blood oxygen, mood cannot be measured directly. Instead, wearables analyse physiological signals that tend to change with emotional states. These include heart-rate variability (HRV), skin temperature, breathing patterns, sleep disruption and small changes in sweat production linked to nervous system activity.
The Fitbit Sense 2 is among the clearest examples. It uses an electrodermal activity sensor to measure stress responses, combining this with heart rate and sleep data to generate daily stress management scores. The device also prompts users to pause or practise breathing exercises when physiological stress indicators rise.
Meanwhile, the Apple Watch takes a more restrained approach. Instead of publishing a single mood or stress score, it uses trends in heart rate and variability to detect moments of elevated strain, offering mindfulness prompts through its wellness features.
The company avoids framing these signals as mental health assessments, emphasising their role in awareness rather than diagnosis.
Assessing Emotional Resilience
Rings and sports-oriented watches provide a different lens. For example, the Oura Ring links sleep stages, skin temperature variation and heart-rate variability to a daily ‘readiness’ score, which many users interpret as an indicator of both physical and emotional resilience.
Periods of anxiety or mental fatigue often coincide with disrupted sleep and elevated nighttime heart rates. Similarly, Garmin watches, widely used by athletes and professionals, frame mood through energy and recovery.
Metrics such as ‘body battery’ and stress tracking combine heart-rate variability, activity and sleep to show how psychological strain can reduce overall capacity, even when physical exertion is low.
Some devices use EEG headsets to monitor brainwave activity, helping detect mood changes. For example, the EPOC X EEG device offers professional-grade brain data with its 14-channel headset system, and saline-based electrodes.
Its rotating headband, user-friendly design, and support for 128 and 256 Hz sampling rates make it an essential tool for researchers and citizen scientists to track changes in the brain.
Other wearables track body temperature and glucose levels, which also affect mood and stress. These biosignals inform the device about how your body responds to stress, providing real-time insights into your mental well-being.
Mapping Emotional Triggers
There are also attempts to track emotion more explicitly. The Feel wristband combines heart rate, skin temperature and electrodermal signals to map emotional states such as calm, excitement or stress. Paired with an app, it aims to help users identify emotional triggers over time.
While no mainstream consumer wearable can directly measure hormones such as cortisol or melatonin, companies are exploring how sweat response, skin temperature and circadian patterns might serve as indirect indicators.
Cortisol, associated with stress, and melatonin, which regulates sleep, remain difficult to track reliably outside laboratory settings. For now, wearables infer their effects through correlated physiological changes.
And as with everything now, interpreting these signals also depends heavily on artificial intelligence. Machine-learning models analyse weeks or months of personal data to establish individual baselines, allowing deviations to be flagged as potential signs of stress or fatigue.
This personalisation is essential as a raised heart rate may reflect anxiety in one person and excitement in another.
Affective Computing Evolution
Companies working in affective computing, which is the study of emotion-aware technology, see this as an early but expanding field. Firms such as Affectiva have focused on emotion detection through facial expressions and voice.
Its software detects complex and nuanced emotions, cognitive states, such as drowsiness and distraction, certain activities and the objects people use. It does that by analysing the human face, vocal intonations and body posture. Wearable manufacturers apply similar techniques to physiological data, aiming to improve accuracy over time.
When it comes to challenges, accuracy remains a central issue. Emotional states are often influenced by context, culture and personal experience, which the sensors cannot capture.
A device may register heightened stress during positive events, such as a promotion or a wedding, or miss quieter forms of emotional strain. For now, these alternative gadgets illustrate both the opportunity and the constraint facing mood-tracking technology.
Sensors are improving, algorithms are becoming more personalised, and awareness of mental health is growing. Yet emotion, or your hormones, remains stubbornly resistant to standardisation.
