New research reveals that slouching can make you sad and may even dumb you down.

We already know that sitting too much can be a lethal (in)activity.

The way we sit also has an important part to play in our physical and psychological health.

One 2012 study found that poor posture can negatively affect our energy levels.

Off the back of this, new research has explored the effect of posture on our emotions.

In the small-scale study, German psychologists took 30 clinically depressed patients and asked them to sit slumped or in an upright position.

While seated, they were asked to imagine themselves in a scene related to positive words such as "beauty" and "enjoyable" or negative words including "exhaustion" and "dejected" flashed on a screen in front of them.

The patients were then asked to recall the words. Those who sat upright had a balanced recall of positive and negative words but slumped patients showed recall "biased towards more negative words," said the study authors in the journal Clinical Psychology and Psychotherapy.

While our mood can determine our posture, it clearly cuts both ways.

A recent TED talk on how body language shapes us, by Harvard Business School social psychologist, Amy Cuddy, catapulted the idea of power poses into public consciousness.

In it, she explains that posture affects the body's levels of cortisol, the stress hormone and testosterone, the so-called dominance or power hormone.

"It seems that our nonverbals do govern how we think and feel about ourselves," Cuddy said. "Also, our bodies change our minds."

In more ways than one.

It's possible that the knock-on effect of posture on testosterone levels, associated with better mental function, can make it more challenging to think clearly.

“The moment you move into a defensive body position, it’s harder for you to do abstract problem solving or think of new, creative options,” said psychologist Erik Peper  in an aptly-titled NY Magazine article, Work Smarter: Unhunch! Slouching Is Making You Dumber.

While this is more more hypothesis than hard fact, "the more you slump, the more your mood slumps," agrees physiotherapist Anna-Louise Bouvier.

How much of a problem it is, "is really a matter of how much we do it," says Bouvier, who has just launched the Happy Body at Work program.

It's hard to stop though because all the sitting we do is making us squishy in the middle, which makes slouching the default.

"It's comfy because we don't have good strength any more, so we slump and let our spine hold us up instead of our muscles," Bouvier explains.

Bouvier surveyed more than 2000 people as part of the Happy Body at Work program. She found they spent, on average, 89 to 91 per cent of their working day seated.

Seventy per cent would spend a further two to three hours on the couch at home watching telly.

"That's pretty consistent with what we see in the literature," she says of the figures.

Scrunching the spine for extended periods caused back pain in about 70 per cent of those surveyed, neck and shoulder pain in about half, headaches in about a quarter and even gut troubles in about a third (a result of "squishing" the guts when we hunch over, she says).

The physical effect is enough to make you want to straighten up - at least for a moment.

But, the problem with posture as she and others emphasise, is that it goes beyond our bodies.

Amy Cuddy suggests trying out power poses for just two minutes a time to manipulate others' perception of us as well as the way we feel.

Bouvier believes posture and sitting are part of a bigger picture that needs to be looked at.

Stress, exercise and sleep and sitting all affect each other, she says.

"It has to be a bigger discussion," she says. "The picture we're seeing in corporations is people are sitting a lot and not exercising enough because they're not sleeping enough and feeling high levels of stress."

Still, understanding the impact of posture is important, Bouvier says.

"We used to think it was just about posture and sitting up, but it's also related to mood."