Diabetes and exercise.

Exercise is frequently recommended in the management of type 1 and 2 diabetes mellitus and can improve glucose uptake by increasing insulin sensitivity and lowering body adiposity. Both alone and when combined with diet and drug therapy, physical activity can result in improvements in glycaemic control in type 2 diabetes. In addition, exercise can also help to prevent the onset of type 2 diabetes, in particular in those at higher risk, and has an important role in reducing the significant worldwide burden of this type of diabetes. Recent studies have improved our understanding of the acute and long term physiological benefits of physical activity, although the precise duration, intensity, and type of exercise have yet to be fully elucidated. However, in type 1 diabetes, the expected improvements in glycaemic control with exercise have not been clearly established. Instead significant physical and psychological benefits of exercise can be achieved while careful education, screening, and planning allow the metabolic, microvascular, and macrovascular risks to be predicted and diminished.

Unexpected changes in the catecholamine content of platelets and plasma during exercise.

Catecholamines are retained within platelets for several hours after plasma catecholamine concentrations have returned to baseline. To determine whether platelet catecholamine concentrations may provide an index of short-term elevations in plasma adrenaline (A) and noradrenaline (NA), the response of plasma and platelet catecholamines to an interval supramaximal, Max (107% VO(2) Max), and submaximal, Submax (37% VO(2) Max), cycling protocol was examined in seven healthy male volunteers, 22-34 years. Despite large rises in plasma NA and A in the Max study (12- and 8-fold increases above baseline, respectively) and smaller rises in the Submax study, the baseline platelet concentrations of A and NA fell significantly in the first 15 min of exercise in both groups. This fall was greater in the SubMax protocol. Catecholamine concentrations then increased slowly in the second half of exercise, but never returned to baseline. The circulating platelet count almost doubled during the exercise period, increasing from 308 to 569 X 10(3) platelets/ml plasma in both studies, returning close to baseline in recovery. These results indicate that at the beginning of exercise there is large rise in plasma catecholamines and the circulating platelet count, with a fall in the platelet catecholamine concentrations. This suggests that a sequestered platelet population, free of catecholamines, is released at the beginning of exercise. This release most probably occurs from the spleen. If this is the case, the reason for a propagation of platelets in the spleen, free of catecholamines, requires further investigation.

Common hip injuries in sport.

As a major weight-bearing joint, normal hip function is fundamental to successful sporting participation. Not only is it important in running-, jumping- and kicking-based activities, it also contributes to the generation and transference of forces in upper limb-dominated activities. Injuries to the hip do not account for a large proportion of the sports physician's workload, but may result in significant morbidity. The wide variety of acute, subacute and chronic injuries, affecting both the joint and surrounding soft tissues, can prove a diagnostic dilemma. The predisposition and the types of injuries around the hip vary with the age of the athlete. The young child rarely sustains a significant injury but one should be aware of orthopaedic conditions common in this age group that may manifest themselves through exercise. The immature skeleton of the adolescent is relatively injury prone and the demands of sport often exceed the capacity of the growing musculoskeletal system. In adults and older athletes, a further spectrum of injury exists, along with the effects of aging tissues and the concerns of degenerative joint disease. Rational treatment is based on a clear diagnosis developed through sound knowledge and a thorough history and examination. For the sports physician, treatments are typically early physical therapy and structured, progressive rehabilitation programmes which are individualised to the needs of the athlete. The spectrum of hip injuries is reviewed with current recommended diagnoses and management.