In this era of fitness trackers, we have easy access to our heart rate at any given moment. Every so often, a number catches your eye as it flashes on your Garmin or Apple Watch while you're sitting ...

You’re familiar with the feeling of your heart pounding in your chest, your blood pulsing through your veins with increasing frequency when you’re scared, stressed, or sweating it out at the gym.

Your pulse is like having a direct line to your heart’s control room, constantly broadcasting information about your cardiovascular health that most people never bother to decode. While everyone knows ...