Overflowing inbox, unattended voicemails, a growing to-do list and the sense that the day is slipping through your fingers. The mid-afternoon slump kicks in just when you have the most to do.
So how do successful types such as company director Fran Elkinson deal with it? The answer may surprise you, says the Daily Mail.
No matter how busy her schedule, Fran turns off her phone, reclines in her office chair and falls asleep.
It may sound counterintuitive, but Fran says not only does napping help her soar through the rest of the day, it has even restored her sight, after she developed stress-related vision problems.
In fact, she goes so far as to say that her afternoon snooze for 20 to 40 minutes a day is of 'critical' importance and the secret to her continued success.
"I have a stressful job, which involves managing more than 100 people," says the 49-year-old from Manchester. "But naptime is non-negotiable. I recline in my office chair and shut out the world. I can't manage without it. It also means I enjoy my social life more, as I feel refreshed."
And Fran is far from the only successful career woman reliant on a daily nap. Perhaps the most famous power-napper was Margaret Thatcher, who ordered her aides not to disturb her between 2.30pm and 3.30pm so she could snooze.
Now, science is catching up. A study by Professor Richard Wiseman, of the University of Hertfordshire, has found taking naps of less than 30 minutes improves our wellbeing and boosts performance. There's even a new phrase for it — "nappiness"!
Last year, a study of 3,000 adults, published in the Journal of the American Geriatrics Society, found that those who took an hour-long nap after lunch did better on cognitive tests.
Taking 40 winks has also been linked to lower blood pressure. A six-year study found people who took a 30-minute siesta three times a week appeared to have a 37 per cent lower risk of heart-related death, thanks to lower blood pressure.
As a result of the growing medical consensus, forward-thinking companies such as Nike, Google and Facebook are embracing the daytime nap, in a bid to boost productivity, and have installed "sleep pods" in their offices.
Not that Fran can claim her daily nap was her own idea. It was prescribed by her doctor — and she was initially dubious.
"Three years ago, I had been through a stressful divorce and was feeling very tired all the time," she says. "Then I started to have problems with my eyes — my vision started to blur. I'd look at my computer and the details on the screen would look opaque, as if everything was underwater."
The mother-of-two was referred to a specialist, who diagnosed central serous retinopathy, a condition that causes fluid to collect in the retina.
The problem can be resolved with laser treatment. However, Fran's doctor said reducing stress might clear it naturally. So, as well as cutting out caffeine and alcohol, he advised her to take a daily power nap of 20 minutes at some point between 2pm and 4pm.
"I was a bit sceptical," says Fran. "I just wanted my vision fixed. What's more, I had a business to run and a home and family to look after. Napping seemed such a waste of time.
"But, worried about my sight, I took my doctor's advice. Almost immediately, I began to feel the benefits. I'd wake up refreshed, rebooted and calm. Within weeks, my vision returned to normal."
Certainly, Fran has an incredibly busy working day as managing director of a marketing firm.
She has also discovered that her father — who, at 82, runs two businesses and still works six days a week — has been power-napping since he was 50.
But there are plenty who frown upon napping, regarding it as a failure to cope.
"Women may well feel guilty about napping, seeing it as a sign of weakness," says Michael Oko, an ear, nose and throat surgeon at the Sleeping Disorders Centre in Harley Street.
"But I liken it to having a snack when you are hungry. Too much and it will spoil your sleep. But 20 minutes might be all you need to invigorate you."
Sleeping for any longer than 45 minutes to an hour, however, can cause the napper to drift into deep wave sleep, a profound slumber that could affect their ability to sleep at night.
And if you are woken up during this phase, then you may feel disorientated.
Dr Tara Swart is neuroscientist in residence at the Corinthia Hotel London, where she suggests how to improve guests' sleep. She says: "Napping is a great way of giving the brain a boost, a bit like plugging in your phone for a short while to boost its charge."
Business owner Tally Bookbinder, 45, is another who swears by her daily nap. The mother-of-one lives in Manchester with her family and is a busy make-up artist, as well as owner of Pro Makeup Academy in Oldham.
She is used to 5.30am starts working on film sets and for magazine shoots. However, by lunchtime, her need to sleep is overwhelming. Which is why she retreats to her car in order to snatch 20 minutes' rest.
"In my car, I feel cocooned from the world. I put the heater on for a few minutes to make sure I'm nice and warm. Then I recline the seat and just drift off.
"I set the alarm on my phone for about 20 to 40 minutes later, depending on how much time I can spare. And, though I wake up feeling a bit groggy for a few minutes, it gives me the punch I need for the rest of the day.
"I've been known to pull into a quiet road or motorway service station and nap. I don't know what people think if they see me, but it doesn't bother me."
If you don't work for a company like Google or have sympathetic deskmates — or even a car handy during your working day — there are other places to go.
Some spas now offer luxury napping treatments intended to help you drift off.
That said, sleep therapist Dr Nerina Ramlakhan, author of the book Fast Asleep, Wide Awake, points out that it isn't vital actually to fall asleep during naptime.
She explains: "The power nap isn't only about sleeping. It's about closing your eyes and relaxing, which is why you can do it sitting at a desk. It's about blocking everything out."
To maximise the benefits of a power nap, it can help to drink coffee just before, known as a coffee nap. Because caffeine takes 20 to 30 minutes to take effect, it will kick in just as you're waking.
In a study by Loughborough University, researchers found that when tired participants took a 15-minute coffee nap, they then went on to make fewer errors in a driving simulator.
For Abby Crammer, a 45-year-old mother-of-two, napping has been the perfect answer to her sleep issues. She says: "My life is full-on. I run my own online business and have two children.
"I was a good sleeper until about seven years ago, when I was getting divorced. I resorted to the occasional sleeping pill, but that made me groggy.
"So I've started napping in my office chair for about 20 minutes a day — and it's fantastic. I feel so much better. The irony is that I now sleep better at night, too.
"It's not about being lazy — it's listening to your body. Women shouldn't feel embarrassed to nap, it's not a sign of weakness."