Combating The Effects Of Your Desk, Part 1

Sitting is a relatively new phenomenon.  For much of our evolutionary history, humans didn’t sit much.  We were always off chasing down, foraging for, and later, farming our food.  Today, the average American sits 9.3 hours a day, many of them at work, hunched at a desk over a computer.
bad computer posture

How Your Desk Is Damaging You

There are quite a few detrimental effects of sitting in front of a desk all day, which I broadly lump into 2 categories: postural and metabolic.

Postural Effects of Desk Sitting

The postural effects of your desk job fall into two broad categories:

Lower Crossed Syndrome / Anterior Pelvic Tilt

Lower Crossed Syndrome (Anterior Pelvic Tilt)

The most noticeable postural distortion associated with prolonged desk sitting is lower crossed syndrome which consists of the following:
  • Shortened/tight hip flexors
  • Inhibited/weak glutes
  • Shortened/tight erector spinae (low back)
  • Inhibited/weak abdominals

When you sit with your hips in a flexed position for more than 1/3 of your day, your hip flexors gradually lose the ability to extend fully.  On the other hand, your glutes are quite stretched when you sit (not to mention squooshed).  Also at work here is the concept of reciprocal inhibition, in which the antagonist (opposite) of a tight muscle becomes weakened.  In this case, we see over-tight hip flexors resulting in inhibited glutes.  Combine all that, and you’ll eventually lose the ability to effectively extend the hip.

Your lower back muscles, forced to contract continually to support the weight of your forward leaning torso, also become overactive and tighten.  On the opposite side, your abdominals become inhibited, again due to reciprocal inhibition.

The practical result of these changes is an altered pelvic tilt. Think of your pelvis as a bowl.  Your tight hip flexors pull the front lip of the bowl downward, and your tight erector spinae pull the rear lip of the bowl upward – these two actions result in an anterior tilt of the pelvis which your inhibited glutes and abs are unable to counteract.

 

anterior pelvic tilt

Anterior pelvic tilt

Upper Crossed Syndrome

Upper Crossed Syndrome

Hand in hand with lower crossed syndrome is, you guessed it, upper crossed syndrome, where a similar effect occurs at the shoulder.  The specific physical changes are:
  • Shortened Shoulder Internal Rotators (pecs, lats)
  • Inhibited/weak shoulder external rotators
  • Shortened, overactive upper traps
  • Inhibited/weak lower traps
  • Inhibited/weak cervical (neck) flexors
Your shoulders-rounded forward, hunched-over-the-keyboard posture allows your pectorals (chest) and other shoulder internal rotators tighten, while your external rotators (which would normally pull your shoulders back) become inactive and weak.
Similarly, as most people type with their arms elevated on a desk, your upper traps (which elevate your shoulders) get overactive and tight while your lower traps (which depressyour shoulders) become inhibited and weak.
Finally, the forward-head posture we tend to assume when reading a computer screen results in tightness of the upper cervical (neck) extensors  and inhibition of the lower cervical flexors.
In sum, your upper body posture now resembles a hunchbacked caveman.

Metabolic Effects of Desk Sitting

The metabolic effects of desk sitting are a little easier to grasp, but more complicated physiologically, so we’ll stick to the basics:
  • Reduced metabolic rate (fewer calories burned)
  • Decreased fat-burning enzymes
  • Decreased insulin sensitivity
  • Decreased HDL (“good”) cholesterol
  • Increases risk of death (in general) up to 40%
To sum up, you’re going to be fatter as a result of all that desk sitting, because you aren’t burning many calories, and your hormone and enzyme profile is very poor for fat loss.  You’re also going to face poorer heart health indicators and potentially higher risk for cancer and heart disease.

Scary enough for you?

In our next episode, we’ll start tackling how to deal with these problems and combat your desk.