Britons spend an estimated 62 million hours each day on Facebook and Twitter, according to a new survey on social media habits.
The poll suggests that around 34 million hours are spent on Facebook each day, with a further 28 million hours on Twitter.
And almost a third (30%) of the UK's 33 million Facebook users are on the network for at least an hour a day, with 13% spending at least two hours on Facebook each day.
More than a quarter (26%) of UK women on Facebook check their pages at least 10 times a day, compared to less than one in five (18%) of men.
Of the UK's estimated 26 million Twitter users, almost a third (31%) spend more than an hour a day on the network, while 14% - more than 3.6 million people - say their daily usage exceeds two hours.
The results are based on a survey of 1,500 adults carried out by OnePoll for online bank, first direct.
The survey also found Facebook was named as the primary social media platform by 59% of people. Only 9% named Twitter as their first-choice network, while 7% chose LinkedIn.
And 11% of Twitter users say it is important for them to have more "followers" on their feed than their friends, compared to just 4% of Facebook users who say it is important to appear more "popular" than their friends.
Dr David Giles, a reader in media psychology at Winchester University, said: "People's social media habits tend to be largely dependent on the number of friends who are on the social network with them.
"If all your friends are on Facebook or Twitter all the time, you risk cutting yourself off from a social life by not doing the same.
"So you spend several hours every day online simply to avoid feeling left out of conversations, or being isolated from your friends."
Rebecca Dye, social media manager at first direct, said: "The survey shows just how central Facebook and Twitter are to people's lives at the moment, often at the expense of other communications and regardless of how often they're actually posting updates or tweeting.
"It's important we engage with our customers in ways that best suit their lives, so the more people are using social media channels to have conversations, or just to 'listen in', the more we need to develop our presence in social media," she added.