Recently, Professor Susan Greenfield, the 21st-century superbrain, revealed how infuriating she found the exhortation to “chill out”. Firing off the latest salvo in the “work/life balance” debate, she said: “I wonder if Beethoven had work/life balance, or Shakespeare.” She went on to suggest that what we need is not to “chill out”, but to have working lives that excite and stimulate us: “To start from the assumption that work is different from life, and not part of it, that it is some chore that has to be kept in its box so you can go and talk to trees or whatever, that’s a wrong distinction, a wrong starting point.”

Some of us live to work and define ourselves by what we do. A culture of personal and professional ambition has sprung up around us, in which achievement, thrills and status are king, fuelling the BlackBerry-hugging, WiFi-loving, social-networking, overstimulated frenzy that so many of us live in. For many people, work is something that gives life interest, purpose and meaning. And, in Greenfield’s opinion, this situation isn’t entirely bad. In simple anatomical terms, constant stimulation, she thinks, can help raise IQ levels. And for many people, being switched on 24/7 is fantastically empowering. Choosing when you work is a new freedom.

The nightclub entrepreneur Amy Sacco thinks 24/7 work culture has been key to her success. “I only have one speed, and that’s ‘Go’. I work seven days a week, and even in the early hours I am still taking texts from people who want to get into the club on whichever continent. I need my BlackBerry – crackberry. I love it. It helps me do 10 times more than I used to. In effect, it accelerated my career.”

Isabella Macpherson, of Arts Co, feels equally secure with her relentless pace of life. “For a lot of people around me, work and play have truly merged,” she says. “This is my life, a large part of which is a business not contained within the four walls of an office. We choose to be on call nonstop because we’re hungry to be involved in interesting and creative things, keen to be at the heart of a mesh of ideas and information. We enjoy what we do and do what we enjoy.”

Technology has freed up working mothers to do their jobs efficiently not just from home, but when it is practical. Used correctly, it is an emancipation of sorts. Tamara Mellon famously “works off her BlackBerry”. When this is said of someone, it means they travel a lot and are available to many people in different time zones. I spoke to one lawyer and mother who often works in synch with Asia: “If something comes up unexpectedly, I am not always sober.” She described her overseas peers as ferociously connected, too, also working all hours. In that sort of culture, being available during what is ostensibly downtime is a way of retaining some lifestyle balance, albeit one that is compromised at times. Most of us have scurried outside to escape the roar of a busy bar, gulp some air, sober up and deal with something only fairly pressing on the phone.

A TV producer told me: “Danny Cohen’s always available. He makes us all feel lazy.” So, when I spoke to the 33-year-old TV wunderkind in charge of BBC Three, I expected a ferociously wired workaholic. In fact, he says, the benefit of working outside office hours is that you can do it “when your energies are right”. But he is eager to point out that this does not mean working all the time. “Over Christmas, I didn’t look at my BlackBerry for 10 days. I have various times when I answer e-mails, but I think it’s dangerous and destructive when e-mail culture breaks up concentration and undermines relationships, which are the really important things.”

The same TV producer also described a lawyer friend who interrupts dinners to take calls, or spends meals with his eyes in his lap while he feverishly “works off his BlackBerry”. This is the sort of 24/7 worker who uses his connectedness and apparent neededness as some sort of status symbol, despite the fact that there are friends and family who need them too. Cohen recognises exactly the sort of person I am talking about. “Creating a work-culture monster, where people don’t have proper breaks,” he says, with great emphasis, “is hugely counterproductive.”

Recognising this creeping institutionalised workaholism and presenteeism has been one of David Cameron’s humanising strategies. Sincere or not, since 2006 it has been a favourite issue of his, and it touches a zeitgeisty nerve. Speaking to a journalist from Coutts Woman magazine last July, he said: “If you care about your work-life balance – and you should – then you can deliver on it, even if it’s a high job in politics. In fact, you must be able to. If you suddenly become exhausted and lose control of your life, you won’t be a very good prime minister, let alone father.”

But it isn’t just about work. It’s about keyboard culture and an overstimulated society that can never switch off. You can pick up messages from your dating website, shop for food, do your daily online weight-loss coaching via your phone, check the news from The Sun to The New York Times – phew-ee – before you’ve even thrown the duvet off the bed. Or, worse, when you get up to pee in the middle of the night.

Despite what Greenfield says, it’s not good when a work e-mail arrives on your BlackBerry when you are trying to wind down, switch off and, dare I say it, chill out.

With the relentless advance of technology, switching off, in every sense of the word, is getting harder. And it’s going to get worse – some might say better – with the development of drugs such as Modafinil, which tests have shown to result in “sustained alertness for up to 88 continuous hours without major side effects”. Really?

Never switching off is bad for you. For all her antichill ire, Greenfield agrees. She urges people to be aware of what they are participating in if they immerse themselves in a 24/7 connected culture. “The 24-hour society brings positives and negatives,” she says. “We shouldn’t assume that bombarding the brain won’t affect us and how we feel, that it won’t have an effect. [Constant stimulation] might help IQ , but it will affect our attention spans. There is some truth in the proposition that we all have ADD now, and that this is linked to screen culture.”

Greenfield likens our state of constant stimulation to that of the adrenaline junkie or the compulsive gambler: “We have an obsession with interaction. With a virtual life, it is harder to hold on to notions of identity.” If you are going to exist in a 24-hour society, she says: “You cannot afford to be complacent.”

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