When she lines up at the start of the London Marathon this weekend, Radio 4’s Saturday Live co-presenter Sian Williams won’t just be facing the challenge of the 26.2-mile course; she’ll be confronting her biggest fear. The last time she ran a marathon, she almost died.
“It was a very humid day and I drank at every single water stop,” she explains, recalling that nightmare day in New York in 2001 when she made a mistake that any amateur might: she drank too much water. “My last memory is crossing the finishing line and having a headache. Various things started to shut down: I couldn’t hear, then I couldn’t see, then my legs went and I couldn’t talk. Two days later I woke up in a New York hospital thinking, ‘Where am I?’ It was incredibly scary.”
Williams was suffering from hyponatraemia, a condition that occurs when an excess of water is consumed, diluting essential salts in the blood. At worst it can result in seizures, coma and death. “I was very, very lucky that it was recognised. I swore never to run that far again.”
What changed? “My mum got terminal cancer and was looked after by a cancer charity called Macmillan, and I thought, ‘I’m going to excise this memory of the dreadful marathon and do it for a good reason.’ So I’m running for Macmillan.
“For me, a lot of it will be psychological, that’s why the cause has to matter. I’m doing it with my mum in mind, and the brilliant nurses who cared for her.” Williams intended to run the New York marathon again last November, only for it to be called off because of Hurricane Sandy. “Luckily Macmillan had a place in London. I was determined to run the 26 miles somewhere!”
As a result she has been pounding the streets in often appalling conditions: 2012 was the UK’s second-wettest year on record, while 2013 brought arctic winds, lingering snow and an especially chilly Easter. All that has taken its toll.
“I’ve had a calf niggle and a stinker of a cold, so two weeks ago I didn’t run the 18 miles I was meant to. It was the first run I’d missed in all my training,” she frets. “Everybody I know who’s running got colds at the same time because we were doing our 20-mile runs in horizontal rain.”
And Williams has another worry: that she’ll struggle if it’s warm. “I’ll need to get advice on how much water I’d need to drink to make sure I don’t get into the same position as last time.”
At least she isn’t striving for a personal best. “Because it’s my first marathon since the disaster, I haven’t set myself a time, I’m just going to soak up the atmosphere. There are tens of thousands of stories like mine. Everybody there will be running for somebody or something, and that’s what will make it such an extraordinary day.”
Coverage of the London Marathon starts at 8:30am on BBC1 and Radio 5 Live