Our first president's formidable physical fitness was the result of decades of active, vigorous life as a military man, a horseman, and a yeoman farmer. In his book about the American Revolution, 1776, historian David McCullough provided a striking description of the image of masculine health Washington presented to the world: "A strapping man of commanding presence, [Washington] stood six feet two inches tall and weighed perhaps 190 pounds. You could distinguish him to be a general and a soldier from among 10,000 people."
The sixth president was not just an early riser (a habit that studies have shown can lead to good overall health): he also got in a cardio workout each day. When he was foreign minister to Russia, for example, Adams reportedly woke up at 5 AM, read from his bible, had a cold bath, and then embarked on a 6-mile walk—all before breakfast. Back in the States, he routinely swam in the Potomac for hours at a stretch, in all weather.
After suffering from asthma as a child, Teddy Roosevelt in effect willed himself to become an enormously robust figure in adulthood—a man who was almost a caricature of the active outdoorsman. He rode horses to exhaustion and camped, hunted, and fished in backcountry wilderness for weeks on end. When in the White House, he boxed—reportedly sparring with men half his age—and even earned a brown belt in judo.
The 31st president is the namesake of the little-known, muscle-straining pastime known as Hoover-Ball. Perhaps best described as a combination of tennis, volleyball, and medicine-ball practice (and scored like tennis), the game was invented by Hoover's personal physician, and involves two teams of three players hurling a six-pound leather ball repeatedly and quickly back and forth over an 8-foot-high net. For more about Hoover-Ball, see this rule sheet.
Ronald Reagan felt strongly enough about personal fitness that in 1983, when he was 72 years old, he penned an article for PARADE magazine detailing his own commitment to healthy living. "Exercise comes pretty naturally to me," he wrote, "since I've done it my entire life." A combination of outdoor and indoor exercise—horseback riding and clearing brush on his California ranch, for example, as well as working out with weights and running on a treadmill—had kept him in shape since his younger years, when he was an avid swimmer, a lifeguard, and a school athlete.
George W. Bush (whose father, George H. W. Bush, celebrated his 90th birthday by going skydiving) was a long-time runner, even finishing the 1993 Houston Marathon in well under four hours. Later, when knee pain made running difficult, he took up mountain biking—and quickly transformed into a zealous rider. Now in his 70s, the 43rd president reportedly still exercises on an elliptical machine, plays golf, and, by all accounts, still bicycles.
Although he admits to an occasional cigarette, the 44th president is widely seen as one of the fittest presidents in history. An avid and lifelong basketball player—and left-handed, to boot, which can make guarding him difficult—Obama routinely gets on the court with a group of Washington-based friends who can keep up with him. He also starts the day with 45 minutes of cardio or weight training in the White House gym.
Also see Eating Habits of U.S. Presidents.