The magazine noted that Ryan's PB is behind Sarah Palin, the Republican nominee for vice-president in 2008, who has run 3:59 .

BBC: Paul Ryan marathon claim: Would you fib about your PB?

Yes that's right, the base metal element lead, Pb, or more exactly the lead-based chemical compound Pb(CH2CH3)4 added to petrol to make car engines run more smoothly.

BBC: Does lead poisoning make you violent?