Author(s): TOPALIDIS, P.1, RAKOWITZ, C.2, PAULITSCH, J.2, SCHABUS, M.1, Institution: SALZBURG UNIVERSITY, Country: AUSTRIA, Abstract-ID: 2368

In elite military contexts such as Special Operations Forces (SOF), sleep is often sacrificed due to operational demands, despite its central role in recovery, performance, and physiological regulation. Yet little is known about how sleep behaves under real-life field conditions, or how scalable interventions can be implemented over time. This longitudinal study followed 80 Austrian SOF soldiers (Jagdkommando) over 12 months, resulting in 21,512 objectively recorded nights. Using the Polar Verity Sense sensor combined with the sleep² app, participants achieved near-daily sleep measurement through validated HRV-based sleep staging. Participants were allocated in a sleep-supportive supplementation group, a sleep training group or control group. Despite challenging operational conditions, small but consistent improvements were observed over time: subjective sleep quality (SSQ) increased (b = +0.01, p < .001) and sensor-based sleep scores (SSC) improved (b = +0.06, p < .007). Sleep efficiency showed a trend towards improvement in the supplements and sleep training groups but not in the control group (F= 3.49, p=.10). Furthermore, sleep onset latency (to 10min continuous sleep) decreased significantly in both the supplement and sleep intervention group but not the controls (F= 2.77, p= .03). The study shows that daily sleep tracking and intervention are feasible and effective even in extreme occupational settings. The combination of wearable HRV sensors and app-based behavioral guidance offers a scalable approach for enhancing resilience and recovery in SOF and other high-performance populations.