How beds work: what they do, why, and how? PART 1
May 26, 2017
We have got used to thinking of ‘technology’ in terms of electronic devices, apps, and connectivity. We’re all using the stuff now. Even the most stubborn of us also recognises that, to get the most out of it, we need to learn and understand a little about how it works. In my case, this usually takes the form of a consultation with one of my kids. They’re effectively on retainer. It works out to be quite expensive.
But there’s a much older technology, which has, and has always had, a huge impact on our lifestyles. Yet few of us give a second thought to how it works. I’m talking about your bed.
Over the course of the next few instalments, I’m going to give you a look “under the hood” of a bed. We’ll look at what it’s for and how it works. You’ll get to know the most important parameters, on first name terms. You’ll have a better idea what to look for, and what will be right for you.
When you shop for a bed, you’ll be able to spot when the well-meaning sales assistant, who was in the kitchenware department until yesterday, doesn’t know what he’s talking about. Quite possibly, he has a profound understanding of non-stick coatings in frying pans, but you’ll see he knows nothing about beds. Be gentle with him.
Most of all, you’ll be better informed and better equipped to use your bed for all its intended purposes. Simply put: you’ll be better in bed.
The butternut squash, the finger, and the knife
There are several reasons that I slept badly, last weekend camping in the Surrey Hills. It would be churlish of me to apportion blame entirely to any single cause, but several possibilities vie for consideration. The zipper on my sleeping was broken, so I repeatedly found myself with my feet poking out into the cold air. My youngest child needed several reminders to stop singing “Nellie the Elephant” in the small hours. I had shared an imprudent quantity of red wine with too few people, too late into the night, bestowing the classic midnight combination: over-stimulation, dehydration, acid reflux, and full bladder. My wakeful state, however, merely brought into sharp focus the biggest problem: my camping mat was horrendously uncomfortable on the hard, stony ground. At only 5mm thick, and made of aged, beaten-up closed cell foam, it just wasn’t doing enough.
So, what did I want it to do?
First and foremost, in this setting, I wanted the mat to distribute pressure.
Imagine you’re poking your finger into a butternut squash. There will be a certain amount of force you can push with: something like the heaviest weight you can bench press with one arm. This force, spread over (divided by) the area of your finger tip, gives a certain level of pressure, which probably is not enough to break through the crust of the squash.
Now imagine you’ve got a knife in your hand, with a sharp point. The sharp point has a much smaller area than your finger-tip. Now, when you push with the same force, it is spread over (divided by) a much smaller area, giving a much higher pressure. This time, you pierce the crust.
Important fact: Pressure is force divided by area.
Similarly, with your body, it’s pressure that does the damage. High pressure on your soft tissue causes pain and bruising. Even moderate pressure interrupts blood circulation, which will lead to discomfort and damage after a time. The higher the pressure, the shorter the time until discomfort is experienced, and before you have to fidget.
There is nothing you can do about the force you exert on the ground: it’s your body weight. What the bed has to do is provide a bigger contact area, to reduce the pressure.
In the next instalment, we’ll look at how it does that.