I’m currently testing the WHOOP 4.0 for sleep tracking, recovery, HRV, and RHR, and I started wondering about potential EMF exposure—specifically its SAR (Specific Absorption Rate) value—since I wear it close to my body at night.

Here are some quick SAR benchmarks from other wearables and phones (measured in W/kg):

• WHOOP 4.0: 0.48–0.67

• Oura Ring: 0.0003

• Samsung Phone: 0.64

• iPhone 15: 0.98

I appreciate that the Oura Ring offers an offline mode, but I didn’t go with it because I can’t wear a ring during my powerlifting sessions.

For context, the FCC SAR limit for wearable devices is 1.6 W/kg averaged over 1 gram of tissue. So WHOOP is well within the safe range. That said, there’s still limited evidence on the long-term health effects of frequent low-level EMF exposure.

Curious to hear your thoughts on this, Zapiens!