Sleep Tracking, Bluetooth Signals, and EMF: What Every Wearable User Should Know
Sleep tracking wearables like the Oura Ring and Apple Watch use Bluetooth Low Energy (BLE), which transmits at 1–10 milliwatts — far below the power of a phone call and well within FCC and ICNIRP SAR safety limits. WHO-commissioned systematic reviews published in 2024–2025 found no causal link between RF-EMF exposure below safety thresholds and sleep disruption. A common mistake is citing ELF (50–60 Hz power line) melatonin studies to argue against 2.4 GHz Bluetooth devices — these are different parts of the spectrum with different biological interaction mechanisms. For those still concerned, enabling airplane or low-power mode at night reduces wireless transmissions while preserving most sensor-based tracking. The more significant risk from sleep trackers may actually be 'orthosomnia' — anxiety driven by obsessing over inaccurate sleep stage estimates that wearables infer from movement and heart rate rather than measure directly.