High-Intensity Exercise May Alter Brain’s Glucose Metabolism 

London: Engaging in high-intensity interval training (HIIT) for only two weeks can help reduce glucose metabolism in all areas of the brain among people suffering from Type 2 diabetes or prediabetes, researchers say.

The findings showed that HIIT training and also moderate forms of exercise can lead to a change in the brain's metabolism as well as improve the whole body's insulin sensitivity. To improve their insulin sensitivity, everyone can choose the form of exercise they are most comfortable with, which also motivates to exercise regularly, said Jarna Hannukainen from the University of Turku in Finland.

Energy is required for the normal functioning of the organs in the body. Many tissues can also use fat or protein as an energy source but others, such as the brain and red blood cells, can only use glucose. Brain insulin-stimulated glucose uptake (GU) is increased in obese and insulin resistant patients, but normalises after weight loss along with improved whole-body insulin sensitivity.

In the study, the researchers wanted to see if a similar effect could be achieved by exercise, without a significant weight loss. They involved participants who were middle-aged, non-exercising men and women, who had prediabetes or Type 2 diabetes for two-weeks of training. HIIT training consisted of 30-second training sessions with 4-minute recoveries in between, whereas traditional exercise consisted of uninterrupted, moderate intensity cycling.

The results, detailed in the Journal of Cerebral Blood Flow and Metabolism, showed that during HIIT training, e.g. ketones and lactates -- high-energy metabolites -- were being formed which the brain could use as a source of energy. Glucose being supplemented with ketones could be one of the explanations for the decreased glucose uptake caused by exercise. Both high-intensity and moderate training led to an improvement in insulin sensitivity, the researchers said.