Does exercise lead to a more muscular heart? Why can an unfit cyclist cycle faster than an olympic runner runs? How do kinetic watches work? We answer your questions in this week's Naked Scientists Podcast, and find out why so many dead bugs end up on their backs, how salmonella gets into an egg, and if it's more efficient to fill your freezer than run it half empty? In the news we hear how farming migrated across Europe, why distant stars might have influenced life on Earth, and why rogue DNA can cause heart failure. Plus, we home in on the parts of the pigeon brain that respond to magnetic fields...