Identifying molecules that control a runner’s high

Avid runners occasionally report a euphoric experience during exercise, commonly known as a runner’s high. Scientists do not fully understand how a runner’s high occurs. In this study, investigators measured small molecules, called micro-ribonucleic acids, in the saliva of athletes (25 male and female collegiate runners) before and after a long-distance run. By comparing the molecular profiles between those who experienced a runner’s high and those who did not, the investigators identified six molecules that could impart running euphoria. Those six molecules targeted brain pathways that respond to opioids and cannabinoids, common drugs of addiction. The investigators concluded that several pathways likely converge to produce running bliss. Future investigations of the genetic and environmental factors that predispose certain individuals to a runner’s high could have broad implications for promoting exercise and improving population health. View the abstract or contact the investigator for more information.

Can a single session of exercise improve anxiety, worry, energy, and fatigue in apprehensive young adults?

Generalized anxiety disorder (GAD) is characterized by frequent worry that interferes with daily life. Unfortunately, GAD often is not successfully treated, so research has examined potential alternative therapies. Research recently supported that a single, 30-minute session of running on a treadmill improved anxiety, worry, and feelings of energy and fatigue in young women with subclinical (ie, not diagnosed) GAD. In the study reported here, the investigators replicated those findings in another group of 16 young adult women with subclinical GAD and extended the findings to a group of 19 young adult men with subclinical GAD. Participants completed questionnaires before and after two sessions: 1) 30 minutes of treadmill running at a vigorous intensity and 2) 30 minutes of sitting. Exercise improved anxiety and feelings of energy in both men and women. Improvements in worry and feelings of energy were stronger in women, including a potentially clinically meaningful improvement. Although this was a relatively small study with physically active young men and women, these findings supported the previously reported positive effects of a single session of exercise among young women with subclinical GAD. It also provided the first evidence for positive effects among young men with subclinical GAD. View the abstract or contact the investigator for more information.

Acute effects of exercise on insulin sensitivity: Is high intensity better?

It is well known that a single bout of exercise and routine exercise training can improve blood glucose clearance following a meal. What is less understood is whether these benefits are due to the calories burned during exercise or longer-term changes within the muscle. In this study, the investigators compared the benefits of routine aerobic exercise training—a single bout of continuous aerobic exercise performed at a moderate intensity or interval exercise performed at higher intensity—for improving insulin sensitivity. Twenty-eight untrained women participated. A unique part of this study was that the participants stayed in a room calorimeter (used to measure the number of calories they burned) for 23 hours and were re-fed the number of calories they burned before measuring their blood glucose clearance. The researchers found that high-intensity interval exercise improved insulin sensitivity 22 hours following exercise—when controlling for calories burned. However, there were no improvements in insulin sensitivity following routine aerobic exercise training or a single bout of continuous exercise performed at moderate intensity. These findings suggest that improvements in insulin sensitivity following exercise training may be at least partially regulated by shifts in calories burned during exercise, and that high-intensity interval exercise may improve insulin sensitivity even when calories consumed equal calories burned. View the abstract or contact the investigator for more information.

Lighting up the brain during exercise

The cognitive and behavioral benefits of exercise are well known. What is less well known are the direct effects of exercise on the brain. Near infrared spectroscopy (NIRS) is an imaging technology. When placed on the scalp, NIRS devices use light to measure changes in blood flow. Changes in blood flow, in turn, reflect local brain activity. What we do not know is whether NIRS devices can measure brain activity during exercise at different intensities. In this study, brain activity linked to a memory and hand movement task was compared while cycling at low, moderate, and high intensities. Thirteen healthy adult men and women, who reported regular exercise habits, participated. The results showed that brain activity linked to the tasks could be identified during low and moderate exercise. As well, brain activity linked to the tasks was comparable during exercise and rest. These findings indicate that NIRS can be used to measure brain activity in real-time during low and moderate cycling exercise. Future studies could use NIRS to directly measure brain activity during exercise in healthy and clinical groups. Scientists could then better understand changes in cognition and behavior resulting from exercise. View the abstract or contact the investigator for more information.

Physical activity in childhood is linked to cognitive performance at midlife

The need for effective strategies to prevent cognitive deficits is important because the prevalence of dementia and milder cognitive deficits is increasing worldwide. In this study, the researchers examined the association between physical activity from childhood to midlife and cognitive performance in midlife. Since 1980, the Cardiovascular Risk in Young Finns study has followed a cohort of 3,596 children (age 3–18 years at the baseline) in 3- to 9-year intervals. Subjects have been questioned about physical activity in all study phases. In 2011, cognitive performance was assessed using a computerized neuropsychological test battery in 2,026 participants (age 34–49 years). A high level of physical activity in childhood, adolescence, young adulthood, and adulthood was found to be associated with better reaction time in midlife—regardless of the physical activity level in other ages. Additionally, a high level of physical activity in both young adulthood and adulthood was associated with better information processing and sustained attention in midlife among men. If these associations are causal, the findings suggest that a physically active lifestyle adopted in childhood, adolescence, and young adulthood and continued into midlife may benefit cognitive performance in middle age and later in life. View the abstract or contact the investigator for more information.