• If you haven’t slept in the last 24 hours: my advice is don’t extravagate, just sleep.
  • If you must extravagate, drink tea, coffee, chocolate or some other caffeinated beverage.
  • Watch out for hostility – you are more prone to start unnecessary fights when sleep-deprived.
  • Use repetition and familiarity to overcome brief moments of tuning out (which are likely happening without you noticing).

If you haven’t slept in the last 36 hours, and you’re medically fit, my heart-felt appeal is for you to put away your money, walk out of the shop and find a bed (preferably your own, or some other safe horizontal surface) on which to sleep. In short, this is a terrible time to be shopping, except perhaps for herbal tea. In this sleep-deprived state, you are less likely to enjoy the experience but you are more likely to unthinkingly answer all questions lobbed in your direction, to make bad decisions and generally regret whatever you take home. In that sense, it’s not much different to going on a sleep-deprived date.

According to articles published in the august (not the August) Journal of Sleep Research, it is likely that your sleep-deprived brain’s electrical activity is particularly low in regions responsible for paying attention (“how did you find those shoes and I didn’t?”); for remembering new information (“did the assistant say leather or canvas?”); for doing simple calculations (“10% discount?”); but, most of all, for making good decisions (“ok, where to next?”).

Moreover, I would give this same advice to most people after just 24 hours of sleep deprivation. After 24 hours of not sleeping, it is precisely a deep, dream-filled, silk-wrapped slumber that is the best luxury you can currently hope to acquire.

“Sleep-deprived shopping is a lot like sleep-deprived dating: you’re less like to enjoy the experience and more likely to regret whatever you end up with.” Sia von D

To understand the importance of sleep for good cognition, it helps to remember that the human brain has its own “clock”. It’s called the suprachiasmatic nucleus and sits around 7 cm behind your eyes. It is normally-well calibrated to a 24 hour cycle, firing fastest at midday and slowest at midnight. But, to further complicate matters, various other brain regions have their own clocks, which are interconnected in ways that are, as yet, poorly understood.

To cut a long and inconclusive scientific journey short, if we want to get the best out of our brain’s shopping systems (the stuffy scientists prefer to call them learning, memory and emotional systems) then we should almost certainly seek to maintain an alignment between all the brain’s various clocks and the Earth’s own daily spin cycle. In other words, there is really no substitute for getting good sleep during the times when our environment is naturally dark and relatively quiet. This tends to be at night unless you’re near the poles – and I don’t mean the Poles, who are very warm people indeed (especially if you find yourself near them at night).

And that’s the way it mostly worked for several thousand years over which time our staggeringly beautiful (although admittedly not perfect and yet disturbingly imperilled) Western civilisation developed. In fact, prior to electricity, adults averaged 10 hours of sleep a night. We are currently averaging 7.5 to 8 hours. And I’m writing this post on six hours of sleep, which is a further indication of how duration can affect quality (again similar to a romantic date). But the point is: I did not, and would never freely, choose today as the day I go extravagating, even for a relatively safe option like a Smythson.

“To those she saw most beautiful,
she gave Strange panacea in a crystal bowl:
They drank in their deep sleep of that sweet wave,
And lived thenceforward as if some control,
Mightier than life, were in them;”

The Witch of Atlas (593-597), P. B. Shelley

Having thrown around impressive-sounding words, even coined a new word, name-dropped a prestigious journal and quoted a brilliant Romantic poet, surely you are now sold on the value, indeed necessity, of getting as much sleep as your body can take each and every night. But what if we find ourselves extravagating in a sleep-deprived state, perhaps jet-lagged in a duty-free lounge, and we simply must get on with it? Is there some sort of panacea we can use to overcome the various cognitive deficiencies we suffer?

Certainly caffeine works. It’s not just clever marketing, or the appeal of attractive baristas or the pleasant aroma. It really does have beneficial psycho-active effects on anyone who is slumber-deprived provided you consume it in sensible quantities. But coffee (or whatever form of caffeine is your cup of tea) is the only cognitive-enhancer I would consider on the criteria of legality and efficacy. And legalities very much matter if you’re sitting in an airport lounge.

Beyond caffeine, sleepy shoppers need to be alert to hostility. You are more prone to anger, which means you are more prone to being social media shamed, and more prone to regretting your behaviour tomorrow even from thousands of miles away. This is not the time to attempt a clever rebuke or subtle put-down. I suggest staying on the straight and narrow when it comes to your shop-based social interactions.

You might also watch for brief moments of mental inattention except, almost by definition, you probably won’t notice them. In a sleep-deprived state, you will be intermittently switching off without necessarily realising it. To help manage this problem, use repetition and familiarity. As painful as this is, if you want to be safe, you need to look repeatedly at the same object, the same shelves, the same shop; ask the same questions twice (a little rephrased if you can manage it) and check and double-check your choices. And stick with the usual brands, colours and styles that you normally choose. Now is less the time to experiment; although, of course, playing it too safe carries its own risks (a topic for another day).

Finally, if you’ve stubbornly disregarded any or all of this advice, and made a stunningly good purchase anyway, then feel free to drag my personal credibility through the social media mud with the Twitter or Instagram hashtag #saperaud (“dare to be wise”).

And if this particular dose of sagacity has failed to quench your thirst, another swig from the refreshing well of von Donia aphorisms awaits you here. And if you would like to be emailed upon the publishing of my upcoming articles then please click here.

Or browse my collection of hand-painted von Donia products thus.