8 Nov 2014

Can shift work make you dumber?

From This Way Up, 1:15 pm on 8 November 2014

Punch Card stx

Dr Chris Smith from the Naked Scientists told This Way Up’s Simon Morton that a new study has shown working anti-social shifts over many years can dent your brain power.  Previously, many studies have examined the health impacts of shift work, confirming elevated risks of heart disease, stroke and diabetes in night workers.

But no data current exist exploring the short and long-term cognitive impacts of shift work. To address this, a team led by Philip Tucker from Swansea University in the UK used data collected by the French National Institute for Statistics and Economic Studies on more than 3000 workers.

These people, who were aged between 32 and 62, underwent tests of brain function ten years apart; memory, mental reasoning and attention tasks were probed. The data showed that individuals who had worked night shifts for over 10 years had the same cognitive test scores as someone up to six and a half years older than them. The team speculate, in their paper in Occupational Environment Medicine, that the results reflect the effects of "circadian stress" caused by defying the body clock.

This stress in turn can damage the hippocampus, a brain structure concerned with learning and memory. However, more cheerily, the effect does appear reversible. Individuals with the same shift work history but who had ceased this working pattern more than 5 years previously showed that their cognition had returned to what would be expected based on their age. According to the researchers, this recovery might reflect the fact that the hippocampus is one of a small number of sites in the brain capable of producing new nerve cells.

Hear Dr Chris Smith from the Naked Scientists talk to Simon Morton