A woman's viral brain illness means her husband has to retell their basic life story every day. But even though the husband's brain is working for two, it led him to start running. And running. And running.
In the video above, Bob Buckley brings us the story of Scott and Sharon Callahan.
The virus that destroyed Sharon's memory is herpes encephalitis, the same virus that 90 percent of Americans have that, in some people, just causes cold sores.
Scott and Sharon plan to keep doing triathlons as long as their bodies hold out.