No significant difference was found in the incidence of cognitive dysfunction 3 months after either general or regional anaesthesia in elderly patients. Thus, there seems to be no causative relationship between general anaesthesia and long-term POCD. Regional anaesthesia may decrease mortality and the incidence of POCD early after surgery.

Postoperative cognitive dysfunction occurs frequently but resolves by 3 months after surgery. It may be associated with decreased activity during this period. Subjective report overestimates the incidence of POCD. Patients may be helped by recognition that the problem is genuine and reassured that it is likely to be transient.

Our finding of less cognitive dysfunction in the first postoperative week in elderly patients undergoing minor surgery on an out-patient basis supports a strategy of avoiding hospitalization of older patients when possible.

The pattern of diurnal variation in cortisol level was significantly related to POCD. Thus, circadian rhythm disturbance or metabolic endocrine stress could be an important mechanism in the development of cognitive dysfunction after major surgery.

To study the occurrence and contributing factors of transient hypoglycemia after pre-exercise ingestion of glucose after a 4-hour fast, 19 well-trained cyclists ingested 50 grams of glucose dissolved in water around noon after having a normal breakfast. The ingestion of the glucose solution was followed by 30 minutes rest after which the subjects cycled for 40 minutes at 60% of the predetermined maximal power output. Every 10 minutes blood was sampled for determination of glucose, catecholamines, and insulin concentrations. In 6 subjects (hypo-group) plasma glucose levels dropped transiently below 3.0 mmol/l, while in the other 13 subjects (non-hypo group) plasma glucose level remained above this level. Although at the onset of exercise the plasma glucose levels were lower in the hypo-group, insulin levels were similar in both groups, suggesting a higher insulin sensitivity in the hypo-group. During exercise, norepinephrine was lower in the hypo-group, indicating a lower sympathetic activity in the hypo-group. The lowest plasma glucose levels in both groups were observed after 20 minutes of exercise, after which plasma glucose concentration returned to normal levels. It is concluded that pre-exercise carbohydrate ingestion after a 4-hour fast is sufficient to induce a transient hypoglycemia. The data suggest that the occurrence of hypoglycemia is determined by a combination of a high insulin sensitivity, a small amount of ingested glucose, and a low sympathetic activity.