Bouts of low blood sugar and brain activity

Repeated episodes of low blood sugar (hypoglycaemia) that are severe enough to cause a loss of consciousness or seizures do not appear to affect intellectual function. Researchers from the Joslin Diabetes Center in Boston, USA, looked at more than 18 years of follow-up data on 1,059 patients. The study showed that intensive therapy reduced the risk of long-term complications, including blindness, kidney disease and neurological decline - but increased the likelihood of severe hypoglycaemia. The average patient age was (after 18 years of follow-up) 47 years. 348 patients reported one to five episodes of severe hypoglycaemia and 59 patients reported more than five (and up to 23) episodes during the study period. Patients completed cognitive function tests at the beginning and the end of the study. The researchers found that changes in scores were unrelated to history of hypoglycaemia. Typical episodes, including episodes severe enough to cause coma or seizures and lasting many minutes in duration had no effect on cognitive function, and no additive effect over time. The brain has a high degree of plasticity but as to specifically why there was no long-term damage due to hypoglycaemic episodes, the answer has yet not been found. Some glucose is available to the brain, even when blood sugar levels are as low as 30 mg/dL to 50 mg/dL, so that the cells don't die. Even so, severe episodes of hypoglycaemia may cause permanent damage, and should be avoided.