DJ Nick Grimshaw has been praised by his station boss after shedding more than half a million listeners over the age of 25 from his Radio 1 breakfast show in the space of three months.
The station's controller Ben Cooper said that losing the older listeners while gaining younger fans to bring down the overall age was fulfilling the "challenge" the presenter had been set.
Grimshaw's programme has a weekly audience of 5.85 million according to new figures from industry body Rajar, down 440,000 in total on the previous quarter.
The morning programme which Grimshaw - who is himself 29 - took over in 2012 has piled on 130,000 15 to 24-year-olds in the past three months while losing older listeners.
Cooper has been trying to reduce the average age of listeners to Radio 1 after the BBC Trust wanted the station to do more to appeal to a younger targer audience.
Since replacing predecessor Chris Moyles the show has lost 1.11 million listeners aged 25 or more, while adding 230,000 under 24s.
Cooper said of the latest figures: "I was asked to build a younger audience for Radio 1 and regenerate the brand, and these figures show we're doing exactly that.
"Grimmy and the Breakfast Show continue to gain young listeners, putting on 130,000 under-24s whilst losing 526,000 over-25s, which is the challenge I set him."
The station has 10.53 million listeners , which like the breakfast show, is down 440,000 on the preceding quarter.
Broadcasting veteran Ken Bruce is among the presenters who have helped Radio 2 to a new record audience, according to the new figures.
The network - which was named UK station of the year at the Radio Academy Awards on Monday night - has seen its weekly listener figures climb to 15.57 million.
Bruce, 63, has hit a new high for his 9.30 to midday show with 8.43 million listeners.
His colleague Chris Evans has also set a new record for his breakfast show audience at 9.83 million - almost four million more than his Radio 1 rival.
Helen Boaden, director of BBC Radio, said: "I am delighted to see Radio 2 gaining both accolades and audiences. The station never fails to surprise and amaze with the diversity of its output, which includes an unrivalled breadth of music alongside news, current affairs, documentaries, religion, arts, comedy and readings.
"It also boasts many of the finest broadcasters in the country and the continuing success of the Chris Evans Breakfast Show is a tribute to all those who work so hard to make the show utterly unique."
Radio 3 has a new audience of 2.09 million which is up by 100,000 on the previous quarter, while Radio 4 is at 10.95 million, down from 11.21 million three months earlier.
Radio 4's flagship early show Today has 7.06 million listeners, slightly down from the previous 7.14 million.