Tempus Fugit, Radio 4

Time flies in a riveting look at how to make life last

As George Harrison sang, "Each day just goes so fast/ I turn around, it's past". Would you like to slow down that mad acceleration towards the grave? Want to know how to live longer, or at least make it seem as though you're living longer? Read on. You'll need your toothbrush.

As Ian Peacock discovered in the riveting Tempus Fugit, we're still not completely sure how our brains process time. I once had the idea that things seem to speed up as we get older because each successive day is an increasingly smaller fraction of our lives, and it was gratifying to hear maths egghead Marcus du Sautoy voice the same theory (words I never expected to write, I must say).

But it's more complex than that, apparently. Car-crash survivors report it happening in slow motion, and David Eagleman, an excitable American neuroscientist, wanted to see if that's just how we're remembering, or whether our time-resolution actually increases during the event.

So he sent a guinea pig, a graduate student called Chess Stetson (oh yes), off the top of a 150ft tower in Dallas into a safety net – it's called Scad diving, and is reportedly terrifying. He was wearing a special watch flashing the time so quickly that it's beyond normal vision. If Chess (who we heard screaming in the background) could read it on the way down, Eagleman explained, then we'd know.

He couldn't, and what Eagleman found is that fear has its own memory track. In fact our brains construct time subjectively, and when we're neurally aroused by new experiences, emotions and perceptions – not necessarily scary ones – time seems to dilate so we can accommodate it all.

So, says Eagleman, we can make it feel that we live longer by injecting novelty into our lives: "Even brushing your teeth with your other hand – anything that switches it up so that you're getting out of the neural ruts that you're in and laying down different sorts of memories."

I tried it, the toothbrush thing, for what I estimated to be 30 seconds. It was 27. So did time slow down, or speed up? Am I nearer my grave, or further away? I'm not entirely sure. Anyway, I'll report back when I've tried the 150ft jump.