San Francisco's hills and busy streets can make it a challenge for runners. But professional runner and UCSF cancer biologist Paddy O'Leary says S.F. is an outstanding running city, and produced "Urban Oasis: A Love Letter to San Francisco" as proof. With Total SF host Peter Hartlaub days away from competing in the grueling Dipsea Race, O'Leary, last year's second-place finisher, offers tips for the Dipsea course and some of his favorite places to train in San Francisco. Hartlaub and O'Leary also urge running-averse co-host Heather Knight to give it a try.Produced by Peter Hartlaub. Music from the Sunset Shipwrecks off their album "Community," Castro Theatre organist David Hegarty and cable car bell-ringing by 8-time champion Byron Cobb. Follow Total SF adventures at www.sfchronicle.com/totalsf Learn more about your ad choices. Visit megaphone.fm/adchoices