PUBLISHED 11/02/2006
At an hour when lampposts carve shadows over empty streets, skunks stroll through urban parks, and most people are comfortably tucked in, Tom Goulet is out sweating, his muscles burning, the stillness of sleep a distant notion. Nearly every night of the week, around midnight, come rain, snow, or howling winds, the Boston venture capitalist laces up his shoes, tucks a cell phone in a fanny pack, and relaxes to the rhythm of his footfalls. "It's almost as peaceful as sleeping," says Goulet, 49. "It's really beautiful to be out there on your own. It's nice and strange to feel the stillness of the city."
Goulet and his comrades in reflective gear know the risks--unseen potholes, inattentive drivers, black ice, and worse, thugs. Running postsunset or presunrise may not be ideal, but for runners like Goulet, who often works from dawn through dusk, it's the only time to run. And for the athlete who competes at night--whether in a New Year's Resolution Run or an ultra event--training in the dark is a necessity. "When the sun goes down, your sense of balance shifts due to loss of peripheral vision," says elite adventure racer Mona Merrill, 37, who needs to prepare for multiday, round-the-clock competitions. "It's important to train your body to adjust."
Night Moves
For years, runners have been warned to forgo working out too close to bedtime because exercise interferes with sleep. The American Academy of Sleep Medicine advises avoiding strenuous exercise for as long as six hours before hitting the sack. "The idea is to prevent the body from producing endorphins and other stimulants that can disturb sleep or lead you to wake up in the middle of the night," says academy spokeswoman Kathleen McCann. But recent research by Shawn D. Youngstedt, Ph.D., an assistant professor in the department of exercise science at the University of South Carolina, suggests that this is a misleading generalization. In two studies, subjects exercised at a moderately high intensity for one or three hours and had no trouble nodding off a mere half hour later. "Evening exercise doesn't disrupt sleep in most people, and sleep quality can improve following exercise," says Youngstedt.
In fact, Youngstedt says that some athletes may benefit from evening workouts, citing recent research among a group of swimmers whose performance peaked between 6 p.m. and 11 p.m. Although the responsible mechanism isn't yet understood, Youngstedt says there are several potential contributing factors. One is body temperature, which tends to be higher later in the day and has been linked to increased strength and reaction time. Another is the release of two hormones important for energy metabolism, cortisol and thyroptopin, which are at their highest levels in the evening. "We all have internally generated body rhythms that dictate when we feel and perform our best," Youngstedt says. "You have to find what works for you."
Merrill, whose nighttime training prepares her for endurance events lasting four to five days, had to experiment to discover her optimal schedule. "If I run hard at night, then I have trouble sleeping," she says. "So my runs in the evening are easy. I call them shake-off runs; they help quiet my mind for sleep. I save speedwork for the morning."
