Do Protein Supplements Boost Endurance Exercise Performance?
Although protein supplements are being used by many athletes, it is still unclear if they provide performance benefits for endurance exercise training. In this study, researchers investigated the effect of protein drinks as opposed to control drinks on adaptations to endurance exercise training. Over a 12-week period, 60 recreationally active young men underwent endurance training three times weekly. The participants were provided either a commonly marketed protein drink (28.7 grams of casein protein) or a control drink to be ingested both after exercise and before sleep. Both groups improved their aerobic fitness (higher maximal oxygen consumption during an exercise test) and endurance performance (lower time in a 1-kilometer cycling time trial). However, these improvements did not differ between the supplement and control groups. This study indicates that recreational athletes will not gain an endurance performance advantage from protein supplementation. View the abstract.
To Exercise More or Eat Less, That Is the Question
Inability to regulate blood sugar (glucose) levels is associated with obesity and type 2 diabetes. While people trying to lose weight choose to eat less or exercise more, mechanisms behind glucose-regulating effects of these practices are not clear. Insulin stimulates skeletal muscle and other tissues throughout the body to take glucose from the blood. Inability of the pancreas to secrete insulin or of muscle to respond to insulin (“insulin resistance”) can cause elevated blood glucose. In this study, 32 young, lean, healthy adults undertook energy deficits of 350 or 700 calories through aerobic exercise or eating less and had their blood taken for glucose and insulin measures over a three-hour period the following morning. Exercise increased muscle sensitivity to insulin, with more exercise demonstrating a greater effect, while energy deficits induced through diet did not. Both exercise and diet decreased pancreatic insulin secretion. These results indicate that exercise and diet have tissue-specific effects in controlling blood glucose and, although preliminary, suggest that aerobic exercise may prevent insulin resistance better than dietary restriction. View the abstract.
Effects of a High-Fat, High-Fructose Diet and Exercise on Brain Aging
Recent research has suggested that metabolic disorders, like obesity and type 2 diabetes, can contribute to brain aging (neuronal senescence), which is often linked to Alzheimer’s disease. While regular endurance exercise (e.g., running) provides numerous health benefits, its potential protection against neuronal senescence in the face of metabolic disorders has not yet been identified. In this study, investigators fed mice a high-fat and sugar (fructose) diet for 12 weeks until obesity and type 2 diabetes were developed. Upon confirmation of these metabolic disorders, the mice were placed on a treadmill running exercise program for 13 weeks while continuing on the same diet. Development of obesity and type 2 diabetes caused inflammation, oxidative stress and advanced neuronal senescence in the hippocampus (a memory-control center) of the brain. On the contrary, endurance exercise remarkably restored blood glucose levels along with weight loss and prevented adverse neuronal anomalies and senescence. These findings suggest that regular running exercise might prevent unfavorable brain aging induced by metabolic disorders. View the abstract.
Physical Activity and Function in Older Age: It's Never too Late!
Despite the known benefits of physical activity to health and physical function in aging, the number of older adults meeting recommended physical activity guidelines remains low. This review paper summarized the most recent body of evidence on the relationship between physical activity, risk of fall-related injuries and physical function among older adults. Results indicate that being physically active (i.e., performing at least 150 min/week of moderate-intensity activity) reduces the risk of fall-related injuries in older people by 32-40%, and this includes severe falls requiring medical care or hospitalization. There was also strong evidence that physical activity improves physical function; not only among the general aging population, but among those with frailty, hip fracture, Parkinson’s disease and stroke. Multi-component activities, a combination of aerobic activity with muscle strengthening and balance activities, are most effective. These findings suggest that it is never too late in life to become physically active. View the abstract or contact the investigator.