Neuroscientists in Singapore have found that people who work night shifts show small reductions in brain volume in areas linked to sleep regulation, emotion and memory. The good news, researchers say, is that these changes appear to be at least partly reversible within about two and a half years of stopping shift work.

What the changes mean in practical terms is still uncertain. While the researchers observed a link between greater volume loss and poorer performance on some cognitive tests, the effect was very small and should be interpreted with caution.

According to the Science Direct, The study analysed MRI scans and long-term health data from more than 14,000 middle-aged and older adults with no major medical conditions who took part in the UK Biobank. Of these, just over 2,100 were shift workers.

Compared with non-shift workers, researchers found modest volume loss in the right thalamus, a key hub involved in memory and information processing, and in the left amygdala, which plays an important role in emotional regulation. These areas are also central to sleep–wake cycles and are often associated with symptoms reported by shift workers, such as fatigue, mood changes and memory difficulties.

After accounting for factors such as age, sex, chronotype and head size, the researchers concluded that the changes may represent an early sign of neural vulnerability linked to long-term disruption of the body’s circadian rhythm.

However, they stress that brain volume loss does not necessarily mean permanent damage. The brain is highly adaptable, and the partial recovery seen after people stopped shift work suggests a potential window for prevention and recovery.

The researchers also note that those unable to adapt neurologically may leave shift-based roles altogether, meaning current shift workers could represent a group whose brains have, to some extent, adjusted to the demands of working through the night.

As the study focused only on older adults, it remains unclear how younger brains respond to prolonged shift work. Further research will be needed to understand who is most affected — and how best to reduce long-term risks — as a significant proportion of the global workforce continues to work outside traditional daytime hours.