As the weather turns colder, Jen Forman will do what she's always done to get her runs in: She'll go to her treadmill in her home, press start and run until she's done. "I will continue to press the speed button to get a treadmill workout done as quickly as possible," said Forman, 38. "But I can't live without it because if it's [bad weather] outside or I have my kids at home, I can't leave and go for a run."