Lisa M. Guth

Short-term exercise training improves flow-mediated dilation and circulating angiogenic cell number in older sedentary adults.

Cardiovascular disease risk increases with age due, in part, to impaired endothelial function and decreased circulating angiogenic cell (CAC) number and function. We sought to determine if 10 days of aerobic exercise training improves endothelial function, CAC number, and intracellular redox balance in older sedentary adults. Eleven healthy subjects (4 men, 7 women), 61 ± 2 years of age participated in 60 min of aerobic exercise at 70% maximal oxygen consumption for 10 consecutive days while maintaining body weight. Before and after training, endothelial function was measured as flow-mediated dilation of the brachial artery and fasting blood was drawn to enumerate 3 CAC subtypes. Intracellular reactive oxygen species (ROS) and nitric oxide (NO) in CD34+ CACs were measured using fluorescent probes and reinforced via real-time quantitative polymerase chain reaction. Flow-mediated dilation improved significantly following training (10% ± 1.3% before vs. 16% ± 1.4% after training; P < 0.05). Likewise, CD34+/KDR+ number increased 104% and KDR+ number increased 151% (P < 0.05 for both), although CD34+ number was not significantly altered (P > 0.05). Intracellular NO and ROS levels in CD34+ CACs were not different after training (P > 0.05 for both). Messenger RNA expression of SOD1, endothelial nitric oxide synthase, and NADPH oxidase 2 and neutrophil cytosolic factor 1 in CD34+ CACs was not significantly altered with training (P > 0.05). In conclusion, 10 consecutive days of aerobic exercise increased flow-mediated dilation and CAC number in older, previously sedentary adults, but did not affect intracellular redox balance in CD34+ CACs. Overall, these data indicate that even short-term aerobic exercise training can have a significant impact on cardiovascular disease risk factors.

Lifelong Parental Voluntary Wheel Running Increases Offspring Hippocampal Pgc-1α mRNA Expression But Not Mitochondrial Content or Bdnf Expression

When exercise is initiated during pregnancy, offspring of physically active mothers have higher hippocampal expression of brain-derived neurotrophic factor (Bdnf) and other plasticity-associated and mitochondria-associated genes, resulting in hippocampal structural and functional adaptations. In the present study, we examined the effects of lifelong parental voluntary wheel running (before, during, and after pregnancy) on offspring hippocampal mRNA expression of genes implicated in the exercise-induced improvement of cognitive function. C57BL/6 mice were individually housed at 8 weeks of age with (EX, n=20) or without (SED, n=20) access to a computer-monitored voluntary running wheel for 12 weeks before breeding. EX breeders maintained access to the voluntary running wheel throughout breeding, pregnancy, and lactation. Male offspring were housed in sedentary cages, regardless of the parental group, and were killed at 8 (n=18) or 28 weeks (n=19). PCR was used to assess mRNA expression of several genes and mitochondrial content (ratio of mitochondrial to nuclear DNA) in hippocampal homogenates. We found significantly higher peroxisome proliferator-activated receptor &ggr; coactivator 1 &agr; (Pgc-1&agr;) mRNA expression in EX offspring compared with SED offspring at 8 weeks (P=0.04), although the effect was no longer present at 28 weeks. There was no difference in mitochondrial content or expression of Bdnf or any other mRNA target between offspring at 8 and 28 weeks. In contrast to exercise initiated during pregnancy, parental voluntary physical activity initiated early in life and maintained throughout pregnancy has little effect on offspring mRNA expression of genes implicated in exercise-induced hippocampal plasticity.

Effects Of Carbohydrate Supplementation On Variable-intensity Exercise Responses In Boys And Men: 856

THESIS: Effects of Carbohydrate Supplementation on Variable-Intensity Exercise Responses in Boys and Men STUDENT: Lisa Guth DEGREE: Master of Science COLLEGE: Applied Technology DATE: July 2009 PAGES: 82 This study examined the physiological and perceptual effects of carbohydrate (CHO) on variable-intensity exercise (VIE) in boys and men. It was hypothesized that CHO would increase RER in boys and men and that this increase would be greater in boys. Additionally, it was hypothesized that RPE would be attenuated by CHO. Five boys (10-12 years) and seven men (18-30 years) consumed CHO or a placebo (PL) beverage before and throughout VIE. VIE included three 12-min sets of cycling; intensity varied every 20-30 seconds between 25, 50, 75, and 125% VO2max. Boys’ post-exercise glucose was higher in the CHO trial than the PL trial and RER was lower in boys than men, but was not affected by trial. RPE increased over time but was not different between groups or trials. Though VIE responses varied between boys and men, CHO ingestion before and during VIE did not provide physiological or perceptual benefits.