Showing papers by "Thomas R. Wójcicki published in 2010"

Plasticity of Brain Networks in a Randomized Intervention Trial of Exercise Training in Older Adults

Abstract: Research has shown the human brain is organized into separable functional networks during rest and varied states of cognition, and that aging is associated with specific network dysfunctions. The present study used functional magnetic resonance imaging (fMRI) to examine low-frequency (.008<.08 Hz) coherence of cognitively relevant and sensory brain networks in older adults who participated in a one-year intervention trial, comparing the effects of aerobic and non-aerobic fitness training on brain function and cognition. Results showed that aerobic training improved the aging brain’s resting functional efficiency in higher-level cognitive networks. One year of walking increased functional connectivity between aspects of the frontal, posterior, and temporal cortices within the Default Mode Network and a Frontal Executive Network, two brain networks central to brain dysfunction in aging. Length of training was also an important factor. Effects in favor of the walking group were observed only after 12 months of training, compared to non-significant trends after six months. A non-aerobic stretching and toning group also showed increased functional connectivity in the DMN after six months and in a Frontal Parietal Network after 12 months, possibly reflecting experience-dependent plasticity. Finally, we found that changes in functional connectivity were behaviorally relevant. Increased functional connectivity was associated with greater improvement in executive function. Therefore the study provides the first evidence for exercise-induced functional plasticity in large-scale brain systems in the aging brain, using functional connectivity techniques, and offers new insight into the role of aerobic fitness in attenuating age-related brain dysfunction.

Internet-delivered physical activity intervention for college students with mental health disorders: a randomized pilot trial.

Abstract: The prevalence of mental health disorders among college students is rising and the increasing rates of anxiety and depression have important societal implications. Physical activity has been proposed as an adjuvant to traditional treatment approaches (i.e. psychotherapy or pharmacotherapy), and the internet is a potentially useful means of delivering physical activity information to the college-aged population. This randomized pilot trial examined the effects of an internet-based physical activity intervention on physical activity, self-efficacy, depression, and anxiety in college students (n = 47) receiving mental health counseling. Physical activity, depression, anxiety, exercise self-efficacy, and barriers self-efficacy were assessed at baseline and post-intervention. There was a significant time effect for physical activity, with both groups increasing their physical activity levels across the 10-week intervention but with a larger increase in the intervention condition (d = 0.68) than the control con...

Construct validation of a non-exercise measure of cardiorespiratory fitness in older adults

Abstract: Cardiorespiratory fitness (CRF) is associated with a decreased risk of all-cause mortality but is rarely assessed in medical settings due to burdens of time, cost, risk, and resources. The purpose of this study was to test the construct validity of a regression equation developed by Jurca and colleagues (2005) to estimate CRF without exercise testing in community dwelling older adults. Participants (n = 172) aged 60 to 80 years with no contraindications to submaximal or maximal exercise testing completed a maximal graded exercise test (GXT) and the submaximal Rockport 1-mile walk test on separate occasions. Data included in the regression equation (age, sex, body mass index, resting heart rate, and physical activity) were obtained via measurement or self-report. Participants also reported presence of cardiovascular conditions. The multiple R for the regression equation was .72, p < .001 and CRF estimated from this equation was significantly correlated with the MET value from the GXT (r = 0.66) and with CRF estimated from submaximal field testing (r = 0.67). All three CRF indices were significantly and inversely associated with reporting more cardiovascular conditions. This research provides preliminary evidence that a non-exercise estimate of CRF is at least as valid as field test estimates of CRF and represents a low-risk, low-cost, and expedient method for estimating fitness in older adults.