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Updated: Jun 28, 2026
A Method for Manipulating Blood Glucose and Measuring Resulting Changes in Cognitive Accessibility of Target Stimuli
Published on: August 12, 2016
Glucose administration prior to a divided attention task improves tracking performance but not word recognition:
Andrew B Scholey1, Sandra I Sünram-Lea, Joanna Greer
1NICM Centre for Study of Natural Medicines and Neurocognition, Brain Sciences Institute, Swinburne University, Melbourne, VIC 3122, Australia. andrew@scholeylab.com
Rationale:
The cognition-enhancing effects of glucose administration to humans have been well-documented; however, it remains unclear whether this effect preferentially targets episodic memory or other cognitive domains.
Objectives:
The effect of glucose on the allocation of attentional resources during memory encoding was assessed using a sensitive dual-attention paradigm.
Materials And Methods:
One hundred and twenty volunteers (mean age 21.60, SD 4.89, 77 females) took part in this randomised, double-blind, placebo-controlled, parallel groups study where each consumed a 25-g glucose drink or a placebo. Half of the participants in each drink condition attempted to track a moving on-screen target during auditory word presentation. The distance between the cursor and the tracking target was used as an index of attentional cost during encoding. Effects of drink and tracking on recognition memory and drink on tracking performance were assessed. Self-rated appetite and mood were co-monitored.
Results:
Co-performing the tracking task significantly impaired memory performance irrespective of drink condition. In the placebo-tracking condition, there was a cost to tracking manifest as greater deviation from target during and immediately following word presentation. Compared with placebo, the glucose drink significantly improved tracking performance during encoding. There were significant time-related changes in thirst and alertness ratings but these were not differentially affected by drink or tracking conditions.
Conclusion:
Tracking but not memory was enhanced by glucose. This finding suggests that, under certain task conditions, glucose administrations does not preferentially enhance memory performance. One mechanism through which glucose acts as a cognition enhancer is through allowing greater allocation of attentional resources.
