Thank you, Nora, for this informative piece! I had a 48 h reading not too long ago. Found out out that even at night I hardly wind down. Stress levels too high. Time to bring the parasympathicus back into play. Breathing excercises do wonders ... checkout Heartmath.com if you're interested in how simple inhale/exhale excercises can reduce stress levels and foster better sleep. And leaving the phone in the kitchen switched off!