THE HEART OF IT ALL

The heart beats about 100,000 times a day, up to 3.5 billion times in a lifetime, pushing blood through the body with jolts “powerful enough to send blood spurting up to three metres if the aorta is severed.” Some 1,680 gallons of blood are pushed through our bodies in a day. “With such an unrelenting work rate, it is a miracle that most hearts last as long as they do.” Still, the heart eventually falters, if something else doesn’t get us sooner. The Hmong people of Southeast Asia are prone to “sudden unexplained nocturnal death syndrome.” “Victims’ hearts simply stop beating while they are asleep,” Bryson writes. At autopsy, their hearts nearly always look normal.