'The older generation is getting younger in terms of mindset, energy and health,' said Brighter MD Steve Dunne.
'The average 50-year-old is likely to visit the same places as their grandchildren and undertake activities such as scuba diving, skiing and trekking,' said Saga Group head of comms Paul Green. 'People in their 50s and 60s now want to do a lot more than just take in the view.'
Weber Shandwick previously held the account for eight years.
It has also emerged that ten of Saga's 17 PR posts have been axed over the past six months.
Saga Holidays' former head of comms Peter Bettley joined The Charitable Foundation as PR manager last December; PR manager Amanda Monroe joins Rail Europe as comms manager next week. Neither will be replaced.