Quotes of the Day

"Exercise is my obsession," declares New York Times science reporter Gina Kolata. Her preference is "spinning," a brutal workout on a stationary bike, which she describes in detail in her new book, Ultimate Fitness: The Quest for Truth About Exercise and Health (Farrar, Straus & Giroux). Kolata does many tasks in her book, describing her life as an ardent exerciser, tracing the history of working out ("Eating alone will not keep a man well," said Hippocrates in 400 B.C. "He must also take exercise") and debunking popular claims (e.g., endorphins and running highs are overrated, she says). Kolata concludes that exercise is more often a marker of health than its cause. But this energetic book will propel many a couch potato into the gym.

• Andrea Sachs