Matching Items (5)
Filtering by
- All Subjects: Exercise--Physiological aspects.
- Creators: Lee, Chong
Description
Cardiovascular disease (CVD) is the number one cause of death in the United States and type 2 diabetes (T2D) and obesity lead to cardiovascular disease. Obese adults are more susceptible to CVD compared to their non-obese counterparts. Exercise training leads to large reductions in the risk of CVD and T2D. Recent evidence suggests high-intensity interval training (HIT) may yield similar or superior benefits in a shorter amount of time compared to traditional continuous exercise training. The purpose of this study was to compare the effects of HIT to continuous (CONT) exercise training for the improvement of endothelial function, glucose control, and visceral adipose tissue. Seventeen obese men (N=9) and women (N=8) were randomized to eight weeks of either HIT (N=9, age=34 years, BMI=37.6 kg/m2) or CONT (N=8, age=34 years, BMI=34.6 kg/m2) exercise 3 days/week for 8 weeks. Endothelial function was assessed via flow-mediated dilation (FMD), glucose control was assessed via continuous glucose monitoring (CGM), and visceral adipose tissue and body composition was measured with an iDXA. Incremental exercise testing was performed at baseline, 4 weeks, and 8 weeks. There were no changes in weight, fat mass, or visceral adipose tissue measured by the iDXA, but there was a significant reduction in body fat that did not differ by group (46±6.3 to 45.4±6.6%, P=0.025). HIT led to a significantly greater improvement in FMD compared to CONT exercise (HIT: 5.1 to 9.0%; CONT: 5.0 to 2.6%, P=0.006). Average 24-hour glucose was not improved over the whole group and there were no group x time interactions for CGM data (HIT: 103.9 to 98.2 mg/dl; CONT: 99.9 to 100.2 mg/dl, P>0.05). When statistical analysis included only the subjects who started with an average glucose at baseline > 100 mg/dl, there was a significant improvement in glucose control overall, but no group x time interaction (107.8 to 94.2 mg/dl, P=0.027). Eight weeks of HIT led to superior improvements in endothelial function and similar improvements in glucose control in obese subjects at risk for T2D and CVD. HIT was shown to have comparable or superior health benefits in this obese sample with a 36% lower total exercise time commitment.
ContributorsSawyer, Brandon J (Author) / Gaesser, Glenn A (Thesis advisor) / Shaibi, Gabriel (Committee member) / Lee, Chong (Committee member) / Swan, Pamela (Committee member) / Buman, Matthew (Committee member) / Arizona State University (Publisher)
Created2013
Description
Purpose: The purpose of this study was to examine the acute effects of two novel intermittent exercise prescriptions on glucose regulation and ambulatory blood pressure. Methods: Ten subjects (5 men and 5 women, ages 31.5 ± 5.42 yr, height 170.38 ± 9.69 cm and weight 88.59 ± 18.91 kg) participated in this four-treatment crossover trial. All subjects participated in four trials, each taking place over three days. On the evening of the first day, subjects were fitted with a continuous glucose monitor (CGM). On the second day, subjects were fitted with an ambulatory blood pressure monitor (ABP) and underwent one of the following four conditions in a randomized order: 1) 30-min: 30 minutes of continuous exercise at 60 - 70% VO2peak; 2) Mod 2-min: twenty-one 2-min bouts of walking at 3 mph performed once every 20 minutes; 3) HI 2-min: eight 2-min bouts of walking at maximal incline performed once every hour; 4) Control: a no exercise control condition. On the morning of the third day, the CGM and ABP devices were removed. All meals were standardized during the study visits. Linear mixed models were used to compare mean differences in glucose and blood pressure regulation between the four trials. Results: Glucose concentrations were significantly lower following the 30-min (91.1 ± 14.9 mg/dl), Mod 2-min (93.7 ± 19.8 mg/dl) and HI 2-min (96.1 ± 16.4 mg/dl) trials as compared to the Control (101.1 ± 20 mg/dl) (P < 0.001 for all three comparisons). The 30-min trial was superior to the Mod 2-min, which was superior to the HI 2-min trial in lowering blood glucose levels (P < 0.001 and P = 0.003 respectively). Only the 30-min trial was effective in lowering systolic ABP (124 ± 12 mmHg) as compared to the Control trial (127 ± 14 mmHg; P < 0.001) for up to 11 hours post exercise. Conclusion: Performing frequent short (i.e., 2 minutes) bouts of moderate or high intensity exercise may be a viable alternative to traditional continuous exercise in improving glucose regulation. However, 2-min bouts of exercise are not effective in reducing ambulatory blood pressure in healthy adults.
ContributorsBhammar, Dharini Mukeshkumar (Author) / Gaesser, Glenn A (Thesis advisor) / Shaibi, Gabriel (Committee member) / Buman, Matthew (Committee member) / Swan, Pamela (Committee member) / Lee, Chong (Committee member) / Arizona State University (Publisher)
Created2013
Description
Introduction: Less than half of U.S. adults meet the aerobic physical activity guidelines to exercise at least 150 minutes a week. An individual's decision to be physically active is influenced by their perceptions of physical activity. To address perceptions, interventions need to be implemented where adults spend one third of their day; the workplace. A number of physical activity interventions have been conducted and few have been successful at improving physical activity; therefore, there is a need to explore novel approaches to improve physical activity in the worksite. The purpose of this pilot study was to examine the impact of a seven-day gratitude intervention on perceptions of physical activity and happiness in the workplace. Methods: Full-time employees at two worksites participated in a seven-day online journaling study. Participants were randomized into the intervention (gratitude) or control group and were assessed for perceptions of physical activity and happiness at baseline, immediate post-test (day 7) and one-week follow-up (day 14). Results: Results of this study indicate that the seven-day gratitude intervention may not significantly improve perceptions of physical activity or increase happiness. Future research should consider assessing the individual's readiness for change at baseline, increasing the length of the intervention, testing participant level of gratitude at baseline and employing a larger sample size.
ContributorsRowedder, Lacey (Author) / Huberty, Jennifer (Thesis advisor) / Chisum, Jack (Committee member) / Lee, Chong (Committee member) / Arizona State University (Publisher)
Created2014
Description
Voluntary exercise has been shown to generate post exercise improvements in executive function within the attention-deficit hyperactivity disorder (ADHD) population. Research is limited on the link between exercise and motor function in this population. Whether or not changes in executive and motor function are observed under assisted exercise conditions is unknown. This study examined the effect of a six-week cycling intervention on executive and motor-function responses in young adult females with ADHD. Participants were randomized to either a voluntary exercise (VE) or an assisted exercise (AE) group. Both groups performed 30 minute cycling sessions, three times per week, at either a voluntary or assisted rate, on a modified Theracycle Model 200 motorized stationary cycle ergometer. The Mann-Whitney U tests were used to detect median differences between groups, and the Wilcoxon signed-rank tests were used to test median differences within groups. Executive function improvements were greater for AE compared to VE in activation (MDNAE = 162 vs. MDNVE = 308, U = .00, p = .076, ES = .79); planning (MDNAE = 51.0 vs. MDNAE = 40.5, U = .00, p = .083, ES = .77); attention (MDNAE = 13.0 vs. MDNVE = 10.0, U = .00, p = .083, ES = .77); and working memory (MDNAE = 10.0 vs. MDNVE = 6.5, U = .00, p = .076, ES = .79). Motor function improvements were greater for AE compared to VE in manual dexterity (MDNAE = 18 vs. MDNVE = 15.8, U = .00, p = .083, ES = .77); bimanual coordination (MDNAE = 28.0 vs. MDNVE = 25.3, U = .00, p = .083, ES = .77); and gross motor movements of the fingers, hands, and arms (MDNAE = 61.7 vs. MDNVE = 56.0, U = .00, p = .083, ES = .77). Deficits in executive and motor functioning have been linked to lifelong social and psychological impairments in individuals with ADHD. Finding ways to improve functioning in these areas is important for cognitive, emotional and social stability. Compared to VE, AE is a more effective strategy for improving executive and motor functioning in young adult females with ADHD.
ContributorsBirchfield, Natasha (Author) / Ringenbach, Shannon (Thesis advisor) / Lee, Chong (Committee member) / Chisum, Jack (Committee member) / Campbell, Kathyrn (Committee member) / Arizona State University (Publisher)
Created2014
Description
The gold standard for bone measurement is DXA (dual energy X-ray absorptiometry). Typically, to observe changes in bone by DXA, a minimum of a 4-month intervention is required. Serum osteocalcin (OST) (a bone formation marker) and quantitative ultrasound (QUS) of the calcaneus can be used as indicators of bone change but the sensitivity and time course of these indices to short term interventions are unknown. The purpose of this study was twofold: to compare monthly changes in OST and QUS in response to jump training and to evaluate the relationship between DXA, OST and QUS. Young women with QUS t-scores less than 1.0 were randomized into a jump training (J) (n=16) or control (C) (n=16). J consisted of a progressive routine of 1 and 2-footed jumping performed 3 days per week for 4 months. Body composition, QUS and OST were measured at baseline, and monthly for 4 months. DXA and 24-hour dietary recalls were completed at baseline and 4 months. Low attrition rate (12.5%) and high compliance (98%) with the exercise intervention was recorded. No significant correlations between QUS and OST existed. No significant differences were observed between groups at baseline in body composition or bone variables. Monthly increases in OST were observed but there were no significant differences over time between groups in any bone variables. OST and QUS may be indicative of short term bone changes but these variables were not specifically sensitive to the jumping intervention in this population of women.
ContributorsHeumann, Kristin Joelle (Author) / Swan, Pamela D (Thesis advisor) / Alvar, Brent (Committee member) / Chisum, Jack (Committee member) / Lee, Chong (Committee member) / Vaughan, Linda (Committee member) / Arizona State University (Publisher)
Created2011