In our study, the women who were not previously exercising but then did what was out of the ordinary for them, acute bursts of exercise, were at a slightly elevated risk of having sudden cardiac death while they exercised.

Despite all of the known benefits of exercise, there are also well-documented associations between acute episodes of exertion and sudden cardiac death. Although relatively rare, these deaths commonly occur in an unexpected fashion among those who appear quite healthy.

The risk of sudden cardiac death during an episode of moderate to vigorous exertion in this large group of women was exceedingly low, even lower than we had found previously in a large group of men.

To our knowledge, this analysis is the first to assess both the transient and long-term risk of sudden cardiac death associated with physical activity among women.

In comparison to a prior study that we did among male physicians, the risk of sudden cardiac death during vigorous exertion was approximately 19 times higher in men than in women. On the other hand, women who exercised four or more hours per week reduced their risk of sudden cardiac death during exercise by about sixty percent.

The race went well but the start was difficult. The gun isn't loud enough.