Good news older readers, a small sugary treat can boost your memory and performance when faced with a difficult task. A long-standing body of research has been bolstered by a new study from the University of Warwick that has concluded that sugar does indeed improve memory and motivation in older adults.

For several decades, scientists have been examining the positive impact glucose has in relation to neurocognitive performance. Many studies have focused on what potential neurological mechanisms could be behind this phenomenon, often concluding that glucose can boost activity in the hippocampus, subsequently improving cognitive functioning.

A new study from the University of Warwick has taken a more psychological approach to the problem, examining the different effects glucose has on mood and motivation in both young and older subjects. The study involved about 50 young adults, aged between 18 and 27, and 58 older adults, aged between 65 and 82.

The subjects were all given either a drink containing either a small amount of glucose or an artificial sweetener. After performing an assortment of memory tasks, the subjects' engagement was measured by following changes in heart rate and self-reported efforts.

Interestingly, despite both the old and young glucose groups showing increased engagement, relative to the placebo group, only the older glucose group showed an improvement in memory performance. So, the younger subjects may have been a little hyped up by the glucose, but it didn't actually improve their performance on the memory tasks.

In the older subjects, the study's objective measurements of engagement revealed the glucose group demonstrated more effort and engagement with the task than the group administered an artificial sweetener. The researchers hypothesize that an increase in blood sugar levels most likely resulted in a short-term boost of energy that enhanced the older subjects' motivation to perform the task. This active engagement with the task is what the researchers suggest is behind the improved cognitive effects.

"Over the years, studies have shown that actively engaging with difficult cognitive tasks is a prerequisite for the maintenance of cognitive health in older age," says Konstantinos Mantantzis, a PhD student working on the project. "Therefore, the implications of uncovering the mechanisms that determine older adults' levels of engagement cannot be understated."

The researchers do note that it is still unclear exactly how energy availability affects cognitive engagement, so this study doesn't suggest sugar being included in specific dietary guidelines for senior citizens. However, if you're a relatively healthy older adult and need a short-term boost to get you performing at your best in the face of a difficult task then a little bit of sugar could certainly help.

The study was published in the journal Psychology and Aging.