BAD HABIT: You're A Night Owl
Runners who shortchange sleep compromise recovery, immunity, and mental sharpness, which can turn an easy workout into a grueling one. "Sleep enhances the restoration of cells that are damaged from running," says Ralph Downey, Ph.D., chief of sleep medicine at California's Loma Linda University Medical Center. Getting enough shut-eye can also ward off "effort headaches." A 1999 study found that distance runners experienced twice the number of headaches as nonrunners. Downey says this is most likely due to the dilation of blood vessels and sinuses that occurs during exercise. The good news: The headaches occurred less often when the runners got more sleep.
Some people are fine with five hours, others require 10. Runners who put greater demands on their bodies tend to benefit from the higher end of that range, says Downey. Note how many hours you get each night in your training log. Review it and look for patterns. Once you figure out your target number, try to hit it each night, particularly during the week leading up to a race.
More: How Sleep Improves Your Performance
BAD HABIT: You Forgo Sunscreen
In 2007, the Archives of Dermatology reported that runners are at a higher risk of developing skin cancer than nonrunners. Researchers found that the occurrence of skin abnormalities increased with mileage, not only because of increased sun exposure, but perhaps because training can suppress immune function, making the body more susceptible to the sun's ill effects. Another study named sweat as a contributor to UV-related skin damage; perspiration increases the photosensitivity of skin, which makes it more prone to burning. "The sun is definitely a job hazard for distance runners," says Deena Kastor, 2004 Olympic Marathon medalist, who was diagnosed with squamous-cell carcinoma and melanoma in 2001.
Before every run, put on a water- or sweat-proof SPF 15 lotion that shields against UVA and UVB rays, says Rodney Basler, M.D., past chairman of the American Academy of Dermatology's Task Force on Sports Medicine. If you have fair skin or a family history of melanoma, follow Kastor's example: She slathers on sunscreen, wears sun-protective clothing, and avoids midday runs.
More: Sun Protection Facts You Need to Know
BAD HABIT: You Never Rest
Overtraining can cause persistent soreness, suppressed immunity, injuries, moodiness, and loss of motivation.
"Rest isn't the absence of training, it's an important component of it," Stolley says. "During recovery periods, your cardiovascular and muscular systems are restored and rebuilt to a higher level—that's where all performance gains are made."
Every training program should have a rest day in addition to two or three easy days (shorter, less-intense runs following harder efforts) each week. If you didn't have a strenuous week, it's okay to cross-train—go for a hike or swim, take a yoga class, or treat your dog to a long walk. But if you're coming off a high-mileage week, reward yourself with a day of total rest. Schedule a massage
or breakfast with a friend so you'll feel like the time off was well spent.
Sign up for your next race.