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Working in an office can make people ‘dimwits’

Working in a dim light can make people ‘dimwits’, new research suggests.

Spending time in poorly lit rooms and offices changes the brain’s structure and cuts the ability to remember and learn.

Trials on rats showed sustained exposure to dim light – designed to mimic that of an office – led to reductions in a chemical that maintains healthy brain connections.

Four weeks of exposure resulted in diminished learning and memory performance, Michigan State University researchers concluded.  

The effects on rats were similar to when people struggle to find their way back to their cars in a busy parking lot after spending a few hours shopping.

Joel Soler, lead author of the new study conducted on Nile grass rats, said: ‘In other words, dim lights are producing dimwits.’

Spending time in poorly lit rooms and offices changes the brain’s structure and cuts the ability to remember and learn

Nile grass rats – which like humans are diurnal and sleep at night – were exposed to two types of light during the experiment.

Michigan State University scientists found those rodents exposed to dim light lost about 30 per cent of capacity in their hippocampus.

This is a small horseshoe-shaped structure in the central brain involved in memory, learning and emotional regulation.

Researchers noted how the rats performed poorly on a spatial task they had trained on previously if they were exposed to dim light.


We’ve heard it all before: desk work is wreaking havoc on our health.

But experts in December warned that, while 86 per cent of Americans work at a desk, few know how to offset the damage.

If you spend at least six hours a day at a desk, your heart attack risk is double what it should be. 

Computers also increase your risk of vision loss by 40 per cent, increase insulin resistance, and affect our mental health.

This culture of working has given rise to the ‘weekend warrior’ who packs a week’s worth of exercise into two days, and after-hours yoga or meditation.

However, research showed that may only have a superficial impact on boosting your health. 

However, the rodents exposed to bright light – such as that of daylight – showed significant improvement on the spatial task.

And when the rats who were exposed to dim light were given four weeks of bright light, their brain capacity and performance on the task recovered. 

The study, published in the journal Hippocampus, is the first to show changes in environmental light leads to structural changes in the brain.

It is estimated that modern office workers, often exposed to poor lighting, spend about 90 per cent of their time indoors. 

Professor Tony Nunez, co-author of the study, said the dim light mimicked ‘the cloudy days of winter or typical indoor lighting’.

And Mr Soler said exposure to dim light led to reductions in a substance called brain derived neurotrophic factor.

This peptide helps maintain healthy connections and neurons in the hippocampus, or the connections that allow neurons to ‘talk’ to one another.

Mr Soler said: ‘Since there are fewer connections being made, this results in diminished learning and memory performance.