James F. Fixx (April 23, 1932 – July 20, 1984) was the author of the 1977 best-selling book, The Complete Book of Running . Best known as Jim Fixx, he is credited with helping start America's fitness revolution, popularizing the sport of running and demonstrating the health benefits of regular jogging. In 1980 he published a follow up book titled . In his books and on television talk shows he often talked about how he jogged an average of 60 miles every week on the basis that the physical exercise considerably increased the average human being's life expectancy.

He is also remembered through comic routines by both Bill Hicks and Denis Leary pointing out that Fixx had failed to obey the first rule in all his books (consult your doctor) and so died, age 52, of a massive heart attack while jogging. The autopsy revealed that cholesterol had blocked one coronary artery almost 100%, a second 80%, and a third 70%.