Are we sitting on a time bomb?

Sitting all day – a serious health hazard

First it was smoking, then it was fat, recently it was sugar, and now it’s sitting that’s bad for us. Increasingly it seems that anything that tastes or feels good is going to be harmful in the long run. Even the so-called J-shaped curve of alcohol and mortality is being questioned.

The good news is that unlike trying to cut down on fat, sugar, alcohol or smoking, it’s relatively easy to give up sitting; all you need to do is to not sit – so for those of you who sit at a desk (or slouch on a couch!) for most of the day, just carry on doing whatever you normally do, but stand and do it.

Are you an ‘active couch potato’?

Too much sitting seems to have different deleterious health effects compared to too little exercise; apparently even if you go for a jog or do your bit in the gym every day, it’s not enough to neutralise the negative effects of being sedentary for the rest of the day.

So if you walk or cycle to work, but then spend the whole day sitting at a desk, followed by slouching on a sofa in the evening, you are still at an increased risk of going to an early grave – not as much as if you hadn’t walked to work, but still at a higher risk compared to someone who doesn’t sit all day. You might even think that you are doing extremely well on a regime of exercising for an hour every day, but really you should could call yourself an ‘active couch potato’ – someone who ‘does their bit’ in a gym, but spends the rest of the day sitting.

If we take a closer look and do a breakdown of the 24 hours in a day it’s easy to see why sitting for prolonged periods might be bad for one’s health; let’s say we sleep on average for 8 hours, that leaves 16 hours of ‘awake time’. If we then spend about an hour of our waking time actively exercising (like running or working out in a gym), that still leaves another 15 hours, or roughly 95% of your waking day to account for.

And it’s what you do in the 95% of your waking hours that count for a lot more than the one hour of running – for most people the majority of their calories are burned during the 95% of this ‘non-sleep-non-exercise time’. (Or ‘NEAT’ as it is officially known – ‘Non Exercise Activity Thermogenesis’).

Little things matter

All those little bits of activity – taking the stairs instead of the lift; walking to the corner shop; doing the housework or gardening – these minor movements use up more calories than going to the gym for one hour every day; the difference in calories burned may not be huge, but an imbalance of as little as 30 calories a day can lead to obesity over the course of a few years – those 30 calories can transform a skinny young girl into a middle-aged-mama.

Easy remedy

And let me just remind you again that this is a very easily remedied situation – no expensive equipment needed; no extortionate gym fees; no difficult diet plan to follow; all you need to do is to stop sitting and stand up instead.

I’m not advocating stopping your regular exercise regime, all I’m suggesting is that if you are spending most of your day sitting, you should either stand up or move around a bit more to break up long periods of sitting.

Why is standing better than sitting for prolonged periods of time?

Mainly because standing involves using the large muscle groups of your leg, shoulder and back much more than sitting does; also shifting your weight from one leg to another plus a whole host of other micro-movements while standing adds up to not only burning extra calories, but also to beneficial changes in various other hormones. One of these beneficial hormones produced by muscles when they are being actively used is called LPL (lipoprotein lipase); and LPL plays a big role in preventing diabetes. Staving off diabetes then has positive knock-on effects on a whole host of other health risk factors.

Middle-age spread

LPL and the other fat controlling hormones that are improved when standing, also control where fat is deposited – people who sit end up with more fat around the middle; and this middle-aged-spread is also an independent risk factor for diabetes.

Sitting is a passive state

If you compare equally slim people who stand for different amounts of time, the ones who stand for longer are less likely to become diabetic – so it seems that it isn’t only a function of being overweight that increases your risk for disease, it’s the levels of the hormones which control your metabolism that matter, and these hormones all benefit from standing.

Too much sitting has different deleterious health effects compared to too little exercise.

How long to stand?

So how many hours should you spend standing every day? It’s hard to come up with an exact figure – studies vary immensely in their recommendations, but around 12 hours of standing and not more than 4 hours of sitting seem to be ideal. Too much standing has other harmful repercussions – so don’t go all out on the standing either.

My personal one-man trial

I decided to put my money where my mouth is and tested out this theory on myself by switching to a standing desk a few months ago and haven’t looked back. I started off by using the kitchen counter as my work desk, but found it to be too disruptive a place in which to be working – 3 children, 4 cats and 1 cleaner were too distracting as the kitchen is the hub of our home – so I took the leap (literally and metaphorically!) and invested in a standing desk, which has now upstaged the normal desk in my bedroom – it also means my regular desk can stay messy, and I have a permanently clear standing desk.

As a rule I don’t like advertising for big companies, but just so that you know how easy it is, I bought my standing desk from Amazon for £160 (I do miss the fact that I used to once upon a time think of the rainforest when I heard the word ‘Amazon’); anyway, it’s not a very fancy desk – it looks like a lectern, but it does the job. If I’m still standing one year down the line, I might invest in a state-of-the-art motorised desk, which can switch from sitting to standing at the press of a button.

One of the reasons why I tried out this standing regime was to see whether the low back pain that I’d had for a few months would improve or not; not only did my back pain get better, so too did many of my ‘metabolic markers’ – and another added benefit is that I sleep more soundly nowadays.

I know I shouldn’t quote the results of a study done on only one person (that one person being myself), but seeing as the results were fairly dramatic, I will include them here – after 4 months of standing for at least 11 hours every day, my blood tests showed that my ‘good cholesterol’ went up by 35%, my ‘bad cholesterol’ went down by 27%, my insulin resistance (aka HOMA-IR) improved by 30%, and my triglycerides went down by 29%. All significant improvements.

And the numbers that matter the most are the triglycerides and HDL; or to be precise it’s the ratio of triglycerides to HDL that’s important; and this improved by an astounding 56% – it went from 0.345 to 0.15 (ideally it should be less than 2).

In case you’re interested in the actual numbers:

	Before Standing	After Standing
HDL ("Good cholesterol")	2.0	2.7 (↑35%)
LDL ("Bad cholesterol")	4.1	3.0 (↓27%)
TRIGLYCERIDES (TG)	0.69	0.4 (↓29%)
HOMA-IR	1.697	1.2 (↓30%)
TG:HDL	0.345	0.15 (↓56%)

Now for some hard evidence from large studies:

The evidence kicks off with a study done in 1953, which showed that bus drivers had a 50% higher risk of having a heart attack compared to bus conductors (who stand all day).

After that, studies comparing sitting and standing went onto the back burner for a few decades, apart from one in 1967 which showed that obese people stand for 3.5 hours less per day than lean people do.

Studies during these interim years focussed on comparing how much active exercise people undertook, without specifically comparing sitting time with standing time.

The idea of ‘inactivity’ being an independent risk factor for disease was first put forward in 2004, and spawned a whole new field of research – that of ‘inactivity physiology’.

Since then studies on inactivity have burgeoned.

LPL is extremely sensitive to inactivity

Studies comparing the effects of an increase in standing time with doing a short bout of vigorous activity have shown that the standing time has a greater beneficial impact on the hormones which control fat metabolism than the short burst of activity does – so if you are going to make only one change, it would be better to make a switch to being less sedentary, rather than going to the gym for an hour every day – both insulin sensitivity and LPL levels improve more with increasing standing time.

So, being sedentary seems to be more detrimental than not doing vigorous exercise; it also appears that the harm from being sedentary is not the same as the harm from not doing vigorous exercise – the human body reacts differently to these two different states.

Or in ‘medical speak’, the metabolic changes from being sedentary are different to the metabolic changes from not doing vigorous exercise.

Ideally you should avoid being sedentary and also do a little bit of vigorous exercise every week; but this isn’t an ideal world, and finding the time to go for a run or to the gym often seems to be at the bottom of one’s list of things to do.

So stop the time bomb from ticking by just getting off your bottom!

References