The value of physical activity to reduce vasomotor symptoms has yet to be determined conclusively. As a result, we used a cross-sectional population-based design to examine the association between self reported physical activity level and hot flash symptoms in 45–54-year-old women. Participants (n = 603) completed a detailed survey to report physical activity level at work, home, and leisure as well as a detailed history of the frequency and severity of hot flash symptoms. Results showed that higher levels of physical activity were significantly associated with increasing odds of moderate or severe hot flashes (P for trend = 0.02). These findings suggest that there is a positive relation between physical activity and moderate or severe hot flash symptoms but no relation between physical activity and the reporting of any hot flashes, daily hot flashes, or hot flashes experienced for greater than 1 year. Am. J. Hum. Biol., 2009. © 2008 Wiley-Liss, Inc.