Stress is a part of modern life, but its long-term effect on our health and productivity can be dramatic. Chronic stress can literally kill you, increasing your risk for heart attack and stroke by up to 50%. Lief tracks and optimizes your resiliency to stress by increasing your natural heart rate variability (HRV), a biomarker of your physical and psychological health. A low HRV score is linked with anxiety, distraction and poor performance - things we'd all prefer to avoid. The good news is, you can improve your HRV and train yourself to stay focused and in control throughout your day. The device's scientifically-validated HRV biofeedback exercises have been used by doctors, psychologists and coaches for decades. It's safe, drug-free and has improved stress, mood and focus for thousands of people. The shape of the Lief is designed to comfortably fit and bend with your torso. The patch is just 6mm thin and sits under your clothing discreetly.