Jill A Kanaley

University of Missouri, Columbia, Missouri, United States

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Publications (129)257.06 Total impact

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    ABSTRACT: Adolescents consume more sugar-sweetened beverages than do individuals in any other age group, but it is unknown how the type of sugar-sweetened beverage affects metabolic health in this population.OBJECTIVE: The objective was to compare the metabolic health effects of short-term (2-wk) consumption of high-fructose (HF) and high-glucose (HG)-sweetened beverages in adolescents (15-20 y of age).DESIGN: In a counterbalanced, single-blind fashion, 40 male and female adolescents completed two 2-wk trials that included 1) an HF trial in which they consumed 710 mL of a sugar-sweetened beverage/d (equivalent to 50 g fructose/d and 15 g glucose/d) for 2 wk and 2) an HG trial in which they consumed 710 mL of a sugar-sweetened beverage/d (equivalent to 50 g glucose/d and 15 g fructose/d) for 2 wk in addition to their normal ad libitum diet. In addition, the participants maintained similar physical activity levels during each trial. The day after each trial, insulin sensitivity and resistance [assessed via Quantitative Insulin Sensitivity Check Index (QUICKI) and homeostatic model assessment of insulin resistance (HOMA-IR) index] and fasting and postprandial glucose, lactate, lipid, cholesterol, insulin, C-peptide, insulin secretion, and clearance responses to HF or HG mixed meals were assessed.RESULTS: Body weight, QUICKI (whole-body insulin sensitivity), HOMA-IR (hepatic insulin resistance), and fasting lipids, cholesterol, glucose, lactate, and insulin secretion or clearance were not different between trials. Fasting HDL- and HDL3-cholesterol concentrations were ∼10-31% greater (P < 0.05) in female adolescents than in male adolescents. Postprandial triacylglycerol, HDL-cholesterol, HDL3-cholesterol, and glucose concentrations were not different between HF and HG trials. The lactate incremental area under the curve was ∼3.7-fold greater during the HF trial (P < 0.05), whereas insulin secretion was 19% greater during the HG trial (P < 0.05).Conclusions: Moderate amounts of HF- or HG-sweetened beverages for 2 wk did not have differential effects on fasting or postprandial cholesterol, triacylglycerol, glucose, or hepatic insulin clearance in weight-stable, physically active adolescents. This trial was registered at clinicaltrials.gov as NCT02058914.
    American Journal of Clinical Nutrition 07/2014; · 6.50 Impact Factor
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    ABSTRACT: Background/Objectives:The purpose of the current study was to determine whether increased physical activity (PA) altered glycemic control while ingesting an energy-balanced high-fructose diet.Subjects/Methods:Twenty-two normal-weight men and women (age: 21.2±0.6 years; body mass index: 22.6 ±0.6 kg/m(2)) participated in a randomized, cross-over design study in which they ingested an additional 75 g of fructose for 14 days while either maintaining low PA (FR+inactive) (<4500 steps/day) or high PA (FR+active) (>12 000 steps/day). Before and following the 2-week loading period, a fructose-rich meal challenge was administered and blood was sampled at baseline and for 6 h after the meal and analyzed for glucagon-like peptide-1 (GLP-1), glucose-dependent insulinotropic peptide (GIP), c-peptide, glucose and insulin concentrations.Results:Plasma insulin, glucose, c-peptide, GIP and GLP-1 concentrations significantly increased in response to the test meal on all test visits (P<0.05). C-peptide incremental area under the curve (AUC) decreased by 10 208 ±120 pmol/l × min for 6 h from pre to post Fr+active intervention (P=0.02) leading to a decrease in plasma insulin total AUC (pre: 58 470.2±6261.0 pmol/l; post: 49 444.3±3883.0 pmol/l; P=0.04) resulting in a decrease Δpeak[Insulin] (P=0.009). Following the FR+active intervention, GIP total AUC significantly decreased (P=0.005) yet only males had a lower total GLP-1 AUC after both interventions (P=0.049). There were no sex differences in GIP levels.Conclusions:Increased PA attenuates the deleterious effects on glycemic control caused by a high-fructose diet. These changes in glycemic control with PA are associated with decreases in insulin and GIP concentrations.European Journal of Clinical Nutrition advance online publication, 21 May 2014; doi:10.1038/ejcn.2014.90.
    European journal of clinical nutrition. 05/2014;
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    ABSTRACT: To determine the interaction between a high fructose diet and PA levels on postprandial lipidemia and inflammation in normal weight, recreationally active individuals.
    Medicine and science in sports and exercise. 05/2014;
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    ABSTRACT: Obesity and high-fructose corn syrup (HFCS)-sweetened beverages are associated with an increased risk of chronic disease, but it is not clear whether obese (Ob) individuals are more susceptible to the detrimental effects of HFCS-sweetened beverages. The purpose of this study was to examine the endocrine and metabolic effects of consuming HFCS-sweetened beverages, and whether weight classification (normal weight (NW) vs. Ob) influences these effects. Ten NW and 10 Ob men and women who habitually consumed ≤355 mL per day of sugar-sweetened beverages were included in this study. Initially, the participants underwent a 4-h mixed-meal test after a 12-h overnight fast to assess insulin sensitivity, pancreatic and gut endocrine responses, insulin secretion and clearance, and glucose, triacylglycerol, and cholesterol responses. Next, the participants consumed their normal diet ad libitum, with 1065 mL per day (117 g·day(-1)) of HFCS-sweetened beverages added for 2 weeks. After the intervention, the participants repeated the mixed-meal test. HFCS-sweetened beverages did not significantly alter body weight, insulin sensitivity, insulin secretion or clearance, or endocrine, glucose, lipid, or cholesterol responses in either NW or Ob individuals. Regardless of previous diet, Ob individuals, compared with NW individuals, had ∼28% lower physical activity levels, 6%-9% lower insulin sensitivity, 12%-16% lower fasting high-density-lipoprotein cholesterol concentrations, 84%-144% greater postprandial triacylglycerol concentrations, and 46%-79% greater postprandial insulin concentrations. Greater insulin responses were associated with reduced insulin clearance, and there were no differences in insulin secretion. These findings suggest that weight classification does not influence the short-term endocrine and metabolic effects of HFCS-sweetened beverages.
    Applied Physiology Nutrition and Metabolism 05/2014; 39(5):544-52. · 2.01 Impact Factor
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    ABSTRACT: The purpose of this study was to compare the effects of short-term low-fat (LF) and high-fat (HF) diets on fed-state hepatic triacylglycerol (TAG) secretion, the content of proteins involved in TAG assembly and secretion, fatty acid oxidation (FAO), and the fatty acid profile of stored TAG. Using selectively bred obese-prone Sprague-Dawley rats, we directly measured fed-state hepatic TAG secretion, using Tyloxapol (a lipoprotein lipase inhibitor) and a standardized oral mixed meal (45% carbohydrate, 40% fat, 15% protein) bolus in animals fed a HF or LF diet for 2 weeks, after which the rats were maintained on their respective diet for 1 week (washout) prior to the liver being excised to measure protein content, FAO, and TAG fatty acid profiles. Hepatic DGAT-1 protein expression was ∼27% lower in HF- than in LF-fed animals (p < 0.05); the protein expression of all other molecules was similar in the 2 diets. The fed-state hepatic TAG secretion rate was ∼39% lower (p < 0.05) in HF- (4.62 ± 0.18 mmol·h(-1)) than in LF- (7.60 ± 0.57 mmol·h(-1)) fed animals. Hepatic TAG content was ∼2-fold higher (p < 0.05) in HF- (1.07 ± 0.15 nmol·g(-1) tissue) than in LF- (0.50 ± 0.16 nmol·g(-1) tissue) fed animals. In addition, the fatty acid profile of liver TAG in HF-fed animals closely resembled the diet, whereas in LF-fed animals, the fatty acid profile consisted of mostly de novo synthesized fatty acids. FAO was not altered by diet. LF and HF diets differentially alter fed-state hepatic TAG secretion, hepatic fatty acid profiles, and DGAT-1 protein expression.
    Applied Physiology Nutrition and Metabolism 04/2014; 39(4):472-9. · 2.01 Impact Factor
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    ABSTRACT: The aim of the study is to evaluate central and peripheral neuromuscular function in the knee extensors (KE) and plantar flexors (PF) after 30 days of unilateral lower limb suspension (ULLS) and to examine the effects of low-load blood flow restricted (BFR) resistance training on the KE during ULLS. Strength, cross-sectional area (CSA), central activation, evoked force, and rates of force development and relaxation were assessed in the KE and PF before and after ULLS in sixteen subjects (9 M, 7F; 18-49 years). Eight of those subjects participated in BFR on the KE three times per week during ULLS (ULLS + Exercise). The ULLS group had decrements in strength and CSA of the KE (16 and 7 %, respectively) and PF (27 and 8 %, respectively) and the ULLS + Exercise maintained strength and CSA of the KE (P > 0.05), but significantly lost strength and CSA in the PF (21 and 5 %; P > 0.05). KE central activation declined 6 % in the ULLS group and was maintained in the ULLS + Exercise group, but a time × group interaction was not evident (P = 0.31). PF central activation was reduced in both groups (ULLS: -7.6 ± 9.9 and -7.9 ±11.6 %; time main effect P = 0.01). A time × group interaction for KE-evoked twitch force (P = 0.04) demonstrated a 9 % decline in the ULLS + Exercise group following the intervention. Evoked PF doublet torque decreased 12 % in both groups (P = 0.002). Central and peripheral neuromuscular function is compromised during unloading. While BFR resistance training on the KE during unloading can maintain muscle mass and strength, it may only partially attenuate neuromuscular dysfunction.
    Arbeitsphysiologie 03/2014; · 2.66 Impact Factor
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    ABSTRACT: Background. Exercise training intervention is underused in the management of type 2 diabetes mellitus in East Africa. Methods. 41 physically-active males with type 2 diabetes mellitus living in Mozambique were recruited and randomly assigned to 12 weeks of supervised exercise of low intensity exercise (LEX), vigorous intensity exercise (VEX), or to a control group (CON). Since there were no differences for any outcome variables between the exercise groups, VEX and LEX were combined into one exercise group (EX). Results. Age and baseline body weight were similar between EX and CON. Plasma glucose at 120 min following glucose load (Glu 120) was significantly reduced in the EX group after training (Glu 120 : 17.3 mmol/L to 15.0 mmol/L, P < 0.05), whereas Glu 120 remained unchanged in the CON (Glu 120 : 16.6 mmol/L to 18.7 mmol/L). After controlling for baseline blood pressure (BP), posttraining systolic BP and diastolic BP were lower in the EX group than in the CON group (EX: 129/77 mm Hg, CON: 152/83 mm Hg, P < 0.05). Conclusion. Adding exercise to already active African men with type 2 diabetes improved glucose control and BP levels without concomitant changes in weight.
    ISRN endocrinology. 01/2014; 2014:864897.
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    ABSTRACT: Type 2 diabetes is associated with poor exercise tolerance and peak aerobic capacity (VO2peak) even when compared to obese non-diabetic peers. Exercise training studies have demonstrated improvements in VO2peak among T2D, yet there is a large amount of variability in this response. Recent evidence suggests that cardiac autonomic modulation may be an important factor when considering improvements in aerobic capacity. To determine the effects of a 16 wk aerobic exercise program on VO2peak in obese individuals, with and without T2D, who were classified as having either high or low cardiovagal modulation (HCVM or LCVM) at baseline. Obese individuals (38 women/19 men; BMI = 36.1 kg/m) were studied in the fasted state. ECG recordings were obtained while seated for 3 min, prior to and after 4 mo of exercise training (4 d/wk, 65% VO2peak). The ECG recording was analyzed for HRV in the spectral domain. Groups were split on a marker of CVM (normalized high frequency (HFnu)) at the 50th percentile, as either high (H) or low (L) CVM. VO2peak only increased with exercise training among those classified as having HCVM, regardless of diabetes status (T2D: HCVM 20.3 to 22.5 mL/kg/min, LCVM 24.3 to 25.0 mL/kg/min; Obese non-diabetics: HCVM 24.5 to 26.3 mL/kg/min, LCVM 23.1 to 23.7 mL/kg/min) (p<0.05). No change in VO2peak was observed for the LCVM group. Changes in weight do not explain the change in VO2peak among the HCVM group. Glucose tolerance only improved among the LCVM group with T2D. Obese individuals, with or without T2D, when classified as having relatively HCVM prior to exercise training, have a greater propensity to improve VO2peak following a 16-week aerobic training program.
    Medicine and science in sports and exercise 07/2013; · 4.48 Impact Factor
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    ABSTRACT: Elevated postprandial glycemic excursions (PPG) are significant risk factors for cardiovascular disease in type 2 diabetes patients. Here we tested if and for how many meals a single bout of exercise would reduce PPG responses to subsequent meals in type 2 diabetes (T2D) patients using continuous glucose monitors (CGMS). We recruited 9 sedentary (<30 minutes/week of exercise) individuals with T2D (BMI: 36.0 ± 1.1 kg/m; age 60.3 ± 1.0 years; HbA1c: 6.3 ± 0.2 %). The subjects consumed a eucaloric diet (51% carbohydrate, 31% fat, 18% protein) consisting of 3 meals, identical in composition, over a 2-day period while wearing CGMS in two different conditions (exercise (EX; one 60 minute bout at 60-75% of heart rate reserve performed prior to breakfast) vs. a sedentary (SED) condition). We quantified 24-h average glucose, PPG-AUC (4 h glucose AUC following meals) and PPG-2 h (2 hour post-prandial glucose). EX significantly reduced average [glucose] during the first 24 hour period (p=0.03). EX caused a reduction in PPG-AUC (p=0.02) for all of the meals over the two days (main effect between conditions). Comparison between the EX and SED conditions at each meal revealed that EX reduced PPG-AUC following the second meal of day 1 (lunch) (p=0.04). PPG-2 h was not significantly different between EX and SED. Although a single EX bout does lower 24-h average [glucose], it only significantly lowered PPG-AUC at the second meal following the bout suggesting that daily exercise may be needed to most effectively improve PPG at the advent of exercise training in T2D patients.
    Medicine and science in sports and exercise 07/2013; · 4.48 Impact Factor
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    ABSTRACT: Adiposity alters acylated ghrelin concentrations, but it is unknown if adiposity alters the effect of exercise and feeding on acylated ghrelin responses. Therefore, the purpose of this study was to determine if adiposity (normal-weight [NW] vs. obese [Ob]) influences the effect of exercise and feeding on acylated ghrelin, hunger, and fullness. Fourteen NW and 14 Ob individuals completed two trials in a randomized counterbalanced fashion including a prior exercise trial (EX) and a no exercise trial (NoEX). During the EX trial the participants performed 1 h of treadmill walking (55-60% VO2peak) during the evening, 12 h prior to a 4 h standardized mixed meal test. Frequent blood samples were taken and analyzed for acylated ghrelin and a visual analogue scale was used to assess perceived hunger and fullness. In NW individuals, EX, compared to NoEX, reduced fasting acylated ghrelin concentrations by 18% (P=0.03) and in response to feeding the change in acylated ghrelin (P=0.02) was attenuated by 39%, but perceived hunger and fullness were unaltered. In Ob individuals, despite no changes in fasting or postprandial acylated ghrelin concentrations with EX, postprandial fullness was attenuated by 46% compared to NoEX (P=0.05). In summary, exercise performed the night prior to a meal suppresses acylated ghrelin concentrations in NW individuals without altering perceived hunger or fullness. In Ob individuals, despite no changes in acylated ghrelin concentrations, EX reduced the fullness response to the test meal. Acylated ghrelin and perceived fullness responses are differently altered by acute aerobic exercise in NW and Ob individuals.
    Journal of Applied Physiology 07/2013; · 3.48 Impact Factor
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    ABSTRACT: We hypothesized that insulin alters plasma free fatty acid (FFA) trafficking into intramyocellular (im) long chain acyl-carnitines (imLCAC) and triglycerides (imTG). Overnight fasted adults (n=41) received intravenous infusions of [U-(13)C]palmitate (0400-0900 h) and [U-(13)C]oleate (0800-1400 h) to label imTG and imLCAC. A euglycemic, hyperinsulinemic (1.0 mU•kg FFM(-1)•min(-1)) clamp (0800-1400 h) and two muscle biopsies (0900 h, 1400 h) were performed. The patterns of [U-(13)C]palmitate incorporation into imTG-palmitate and palmitoyl-carnitine were similar to those we reported in overnight postabsorptive adults (saline control) - the im-palmitoyl-carnitine enrichment was not different than and correlated with imTG-palmitate enrichment for both the morning (r=0.38, P=0.02) and afternoon biopsy samples (r=0.44, P=0.006). Plasma FFA concentrations, flux and the incorporation of plasma oleate into imTG-oleate during hyperinsulinemia were ~ 1/10th of that observed in the previous saline control studies (P<0.001). At the time of the second biopsy the enrichment in oleoyl-carnitine was <25% of that in imTG-oleate and was not correlated with imTG-oleate enrichment. The imNEFA-palmitate:imTG-palmitate enrichment ratio was greater (P<0.05) in women than men, suggesting that sex differences in im-palmitate trafficking may occur under hyperinsulinemic conditions. We conclude that plasma FFA trafficking into imTG during hyperinsulinemia is markedly suppressed and these newly incorporated FFA fatty acids do not readily enter the LCAC pre-oxidative pools. Hyperinsulinemia does not seem to inhibit the entry of fatty acids from imTG pools that were labeled under fasting conditions, possibly reflecting the presence of two distinct imTG pools that are differentially regulated by insulin.
    AJP Endocrinology and Metabolism 07/2013; · 4.51 Impact Factor
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    ABSTRACT: Objective:Short-term exercise training improves glycemic control, but the effect of short-term training on postprandial satiety peptide responses or perceived satiety remains unknown. We tested the hypothesis that short-term aerobic exercise training (15 days) would alter postprandial pancreatic and gut peptide [pancreatic polypeptide (PP) and peptide YY (PYY)] responses and perceived appetite and satiety in obese individuals.Subjects:Thirteen healthy obese men and women (age: 42±2 y; BMI: 30-45 kg/m(2))Measurements:Subjects were studied before and after 15 days of training (walking 1 h at 70-75% VO2peak). On the study day, subjects consumed 1500 kcal as 6 meals (250 kcal: 9 g protein, 40 g CHO, 6 g fat) while blood samples and satiety measurements were taken at baseline and every 20 min for 12 h. Blood was analyzed for pancreatic polypeptide (PP), peptide YY (PYY), glucose, and insulin levels. Appetite and satiety was assessed with a visual analog scale throughout the day.Results:Incremental area under the curve (iAUC) for PP increased significantly with training (pre 2788±753; post 3845±830 pg/ml·min for 12-h, P<0.001), but there was no difference in the PP response to each meal. The initial PP response to the first meal increased (ΔPPmin 20-0: pre 86±25; post 140±36 pg/ml, P<0.05) with training. PYY iAUC showed no significant changes with training but showed a significant main effect of time across meals, with the largest response being to the first meal (P<0.005). There were no changes in satiety, glucose, or insulin levels with training.Conclusion:Short-term exercise training increases postprandial PP concentrations in obese individuals; however, PYY levels and glycemic control remain unaffected. Both PP and PYY show meal-induced increases at all meals but PYY has a greater response at the first meal with reduced responses at subsequent meals.International Journal of Obesity accepted article preview online, 22 May 2013; doi:10.1038/ijo.2013.84.
    International journal of obesity (2005) 05/2013; · 5.22 Impact Factor
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    ABSTRACT: PURPOSE: The incretin hormones glucagon-like peptide-1 (GLP-1) and glucose-dependent insulinotropic polypeptide (GIP) help regulate postprandial triacylglycerol (TAG) and insulin concentrations, but the effects of acute aerobic exercise on GLP-1 or GIP responses are unclear. The purpose of this study was to determine if reductions in postprandial TAG and insulin with exercise are associated with GLP-1 and GIP responses. METHODS: Thirteen normal-weight (NW) and 13 Obese (Ob) individuals participated in two, 4-d trials in random order including an exercise (EX) and a no exercise (NoEX) trial. Diet was controlled during both trials. The EX trial consisted of 1 h of treadmill walking (55-60% of VO2peak) during the evening of day 3 of the trial, 12 h prior to a 4 h mixed meal test on day 4, during which frequent blood samples were taken to assess postprandial lipemia, glycemia, insulin, c-peptide, GIP, and GLP-1 responses. Insulin secretion was estimated using the Insulinogenic Index and insulin clearance was estimated using the ratio of insulin to c-peptide. RESULTS: Postprandial TAG's were 29% lower after EX in Ob individuals (P<0.05) but were not significantly altered in NW individuals (P>0.05). The drop in postprandial high-density lipoprotein cholesterol was attenuated with EX in Ob individuals (P<0.05). Insulin responses were 14% lower after EX in Ob individuals (P<0.05), and this was associated with reduced insulin secretion (P<0.05), with no change in insulin clearance (P>0.05). Glucose, c-peptide, GIP, and GLP-1 were not different between trials. CONCLUSION: A 1 h bout of moderate intensity aerobic exercise the night prior to a mixed meal attenuates TAG and insulin responses in Ob, but not NW, individuals, an effect not associated with altered GLP-1 or GIP responses.
    Medicine and science in sports and exercise 04/2013; · 4.48 Impact Factor
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    ABSTRACT: OBJECTIVE: The purpose of this study was to compare postprandial satiety regulating hormone responses (pancreatic polypeptide [PP], peptide tyrosine tyrosine [PYY]) and visual analogue scale (VAS) assessed perceived appetite and satiety between liquid high protein (HP) and high carbohydrate (HC) meals in obese women during acute (24-h) caloric restriction. DESIGN: Eleven obese pre menopausal women completed two conditions in random order in which they consumed 1500 calories as six 250 calorie HP meals or six 250 calorie HC meals over a 12 h period. Blood samples were taken at baseline and every 20 min thereafter and analyzed for PP and PYY concentrations and related to VAS assessed perceived hunger and fullness. The incremental area under the curve (iAUC) was used to compare postprandial responses. RESULTS: The 12 h PP and PYY iAUC were greater (P≤0.05) during the HP condition (PP: 4727±1306 pg/ml•12 h, PYY: 1373±357 pg/ml•12 h) compared to the HC condition (PP: 2300±528 pg/ml•12 h, PYY: 754±246 pg/ml•12 h). Perceived hunger and fullness were not different between conditions (P>0.05). The greatest changes in PYY and perceived fullness occurred after the morning meals during both conditions. CONCLUSIONS: These data suggest that in obese women during acute caloric restriction prior to weight loss 1) liquid HP meals, compared to HC meals, result in greater postprandial PP and PYY concentrations, an effect not associated with differential appetite or satiety responses, and 2) meal induced changes in PYY and satiety are greatest during the morning period, regardless of dietary macronutrient composition.
    European Journal of Endocrinology 01/2013; · 3.14 Impact Factor
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    ABSTRACT: Objective Long, uninterrupted bouts of sedentary behavior are thought to negatively influence postprandial glucose and insulin concentrations. We examined the effects of a 1-h bout of morning exercise versus intermittent walking bouts of short duration on glucose excursions and insulin secretion over 12-h. Materials/Methods Eleven young, obese individuals (18-35y, BMI > 30 kg/m2) with impaired glucose tolerance were studied on three 12-h study days: 1) sedentary behavior (SED); 2) sedentary behavior with 1-h morning exercise (EX) at 60-65% VO2peak; and 3) sedentary behavior with 12-hourly, 5-min intervals of exercise (INT) at 60-65% VO2peak. Meals (1046 kJ/meal) were provided every 2-h. Blood samples were collected every 10 min and measured for glucose, insulin, and c-peptide concentrations. Results Glucose iAUC (12-h) was attenuated in the INT and SED conditions compared to the EX condition (P < 0.05). Glucose concentrations were higher in the EX compared to the SED condition for ~ 150 min (20% of the study day), and comparison of the EX-INT study days revealed that glucose concentrations were greater for ~ 240 minutes (~ 1/3 of the 12-h day). In the SED condition, the 12-h insulin iAUC was ~ 15% higher (P < 0.05) compared to the INT and EX conditions. Insulin production rate was found to increase ~ 20% with INT exercise vs. the SED and EX condition (P < 0.05). Conclusions Short, frequent periods of exercise attenuated glucose excursions and insulin concentrations in obese individuals to a greater degree than an equal amount of exercise performed continuously in the morning.
    Metabolism: clinical and experimental 01/2013; · 3.10 Impact Factor
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    ABSTRACT: The aim of this study was to compare postprandial lipemia, oxidative stress, antioxidant activity, and insulinemia between a three and six isocaloric high-carbohydrate meal frequency pattern in obese women. In a counterbalanced order, eight obese women completed two, 12-h conditions in which they consumed 1,500 calories (14% protein, 21% fat, and 65% carbohydrate) either as three 500 calorie liquid meals every 4-h or six 250 calorie liquid meals every 2-h. Blood samples were taken every 30 min and analyzed for triacylglycerol (TAG), total cholesterol, high-density lipoprotein cholesterol, low-density lipoprotein cholesterol, oxidized low-density lipoprotein cholesterol, myeloperoxidase, paraoxonase-1 activity, and insulin. The TAG incremental area under the curve (iAUC) during the three meal condition (321 ± 129 mg/dl·12 h) was significantly lower (P = 0.04) compared with the six meal condition (481 ± 155 mg/dl·12 h). The insulin iAUC during the three meal condition (5,549 ± 1,007 pmol/l(.) 12 h) was significantly higher (P = 0.05) compared with the six meal condition (4,230 ± 757 pmol/l(.) 12 h). Meal frequency had no influence on the other biochemical variables. Collectively, a three and six isocaloric high-carbohydrate meal frequency pattern differentially alters postprandial TAG and insulin concentrations but has no effect on postprandial cholesterol, oxidative stress, or antioxidant activity in obese women.
    Obesity 01/2013; 21(1):123-9. · 3.92 Impact Factor
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    ABSTRACT: Persons with Down syndrome (DS) exhibit low muscle strength that significantly impairs their physical functioning. The Ts65Dn mouse model of DS also exhibits muscle weakness in vivo and may be a useful model to examine DS-associated muscle dysfunction. Therefore, the purpose of this experiment was to directly assess skeletal muscle function in the Ts65Dn mouse and to reveal potential mechanisms of DS-associated muscle weakness. Soleus muscles were harvested from anesthetized male Ts65Dn and wild-type (WT) colony controls. In vitro muscle contractile experiments revealed normal force generation of non-fatigued Ts65Dn soleus, but a 12% reduction in force was observed during recovery from fatiguing contractions compared to WT muscle (p<0.05). Indicators of oxidative stress and mitochondrial oxidative capacity were assessed to reveal potential mechanisms of DS-associated muscle weakness. Protein expression of copper-zinc superoxide dismutase (SOD1), a triplicated gene in persons with DS and Ts65Dn mice, was increased 25% (p<0.05) in Ts65Dn soleus. Non-triplicated antioxidant protein expression was similar between groups. Lipid peroxidation was unaltered in Ts65Dn animals but protein oxidation was 20% greater compared to controls (p<0.05). Cytochrome c oxidase expression was 22% lower in Ts65Dn muscle (p<0.05) while expression of citrate synthase was similar between groups. Microarray analysis revealed alteration of numerous pathways in Ts65Dn muscle, including: proteolysis, glucose and fat metabolism, neuromuscular transmission, and ATP biosynthesis. In summary, despite biochemical and gene expression differences in soleus muscle of Ts65Dn animals, the functional properties of skeletal muscle likely contribute a minor part to the in vivo muscle weakness.
    AJP Regulatory Integrative and Comparative Physiology 10/2012; · 3.28 Impact Factor
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    ABSTRACT: OBJECTIVES: Women with type 2 diabetes (T2D) show greater rates of mortality due to ischemic heart disease than men with T2D. We aimed to examine cardiovascular and autonomic function responses to isometric handgrip (IHG) exercise between men and women with T2D, before and after an exercise training program. MATERIALS/METHODS: Hemodynamic responses were measured in 22 men and women with T2D during and following a 3-min IHG test, and before and after 16 wks of aerobic exercise training. RESULTS: Women had a smaller decrease in mean arterial pressure (MAP) and systolic blood pressure (BP) during recovery from IHG (ΔMAP(REC)) than men pre- and post-training (P<0.05). Men showed a greater reduction in diastolic BP during recovery from IHG (P<0.05), and exercise training improved this response in men but not in women (men, pre-training: -13.9±1.8, post-training: -20.5±5.3mmHg vs. women, pre-training: -10.7±1.7, post-training: -4.1±4.9mmHg; P<0.05). Men had a greater reduction in sympathetic modulation of vasomotor tone (P<0.05), as estimated by blood pressure variability, following IHG. This response was accentuated after training, while this training effect was not seen in women. Post-training ΔMAP(REC) was correlated with recovery of low frequency component of the BP spectrum (ΔLF(SBPrec), r=0.52, P<0.05). CONCLUSIONS: Differences in BP recovery immediately following IHG may be attributed to gender differences in cardiovascular autonomic modulation. An improvement in these responses occurs following aerobic exercise training in obese men, but not in obese women with T2D which reflects a better adaptive autonomic response to exercise training.
    Metabolism: clinical and experimental 08/2012; · 3.10 Impact Factor
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    ABSTRACT: Individuals with asthma frequently suffer with a decrease in quality of life. Yoga has been shown to improve autonomic function in the healthy population and has been used as an alternative therapy to help improve symptoms associated with various diseases. The purpose of this study was to assess whether 10 weeks of yoga training can improve quality of life and heart rate variability (HRV) in patients with asthma. Nineteen (19) females were randomly assigned to a yoga group or a control group for a 10-week intervention while still following guidelines established by their physician. All subjects answered the St. George's Respiratory Questionnaire (SGRQ) to assess quality of life and performed an isometric handgrip exercise test to assess HRV. Based on the SGRQ, significant improvements (45%, p < 0.05) in quality of life were observed with the yoga training, while no changes were found in the control group. Resting hemodynamic measures improved significantly in the yoga group compared to the control group (p < 0.05). The yoga group decreased parasympathetic modulation (HFnu [normalized units]) pre- to postintervention (0.45 ± 0.60 to 0.35 ± 0.06 nu, p<0.05, respectively) in response to the isometric forearm exercise (IFE), whereas the control group did not change. Additionally, the yoga group increased sympathetic (LFnu) (pre 0.47 ± 0.07 to post 0.60 ± 0.07 nu, p < 0.05) and sympathovagal modulation (logLF/HF) (pre 4.61 ± 0.39 to post 5.31 ± 0.44, p < 0.05, respectively) during IFE with no change in the control group. Conclusions: Yoga training improved quality of life in women with mild-to-moderate asthma and resulted in decreased parasympathetic and increased sympathetic modulation in response to an IFE.
    Journal of alternative and complementary medicine (New York, N.Y.) 07/2012; 18(8):749-55. · 1.69 Impact Factor
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    ABSTRACT: The vascular endothelium secretes a balance of dilator and constrictor substances which regulate vascular tone. During ischemic stress, this balance changes. After a short period of ischemia, a protective mechanism known as reactive hyperemia (RH) contributes to a post-ischemic increase in blood flow. The agents regulating this phenomenon remain controversial. The purpose of this study was to examine whether aspirin regulates vascular endothelial function following ischemia. Sixteen healthy volunteers presented for two visits, each serving as their own control, and randomized to receive 500 mg aspirin or placebo. Forearm blood flow (FBF) was measured at baseline and during reactive hyperemia (RH) which was induced by five minutes of arterial occlusion. Blood samples were analyzed for vWF and lipids. After ischemia, RH was attenuated when subjects were pre-medicated with 500 mg aspirin compared to placebo: AUC[aspirin] = 1450 +/- 201 mL/100 mL tissue/min vs. AUC[pIacebo] = 2207 +/- 294 mL/100 mL tissue/min; (p < 0.05). Separation of the subjects with high HDL or low HDL levels resulted in a similar peak FBF response with placebo, but in the high-HDL group only, aspirin ingestion attenuated peak FBF after ischemia compared to the placebo condition (22.6 +/- 1.7 m/100 mL tissue/min vs. 33.5 +/- 3.2 mL/100 mL tissue/min, respectively) (p < 0.05). Aspirin partially regulates the RH response following ischemia compared to placebo, and this effect appears to be more profound when adjusting for plasma HDL concentration in healthy individuals. This suggests that the post-ischemic RH response may be partially mediated by arachidonic acid-derived mediators such as the prostaglandins.
    European review for medical and pharmacological sciences 02/2012; 16(2):143-50. · 1.09 Impact Factor

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1k Citations
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Institutions

  • 2011–2014
    • University of Missouri
      • Department of Nutrition and Exercise Physiology
      Columbia, Missouri, United States
  • 2013
    • Duke University Medical Center
      Durham, North Carolina, United States
    • University of Illinois, Urbana-Champaign
      • Department of Kinesiology and Community Health
      Urbana, IL, United States
  • 2002–2012
    • State University of New York Upstate Medical University
      • • Department of Medicine
      • • Department of Orthopedic Surgery
      Syracuse, NY, United States
  • 1999–2012
    • Syracuse University
      • Department of Exercise Science
      Syracuse, NY, United States
  • 2007
    • Florida State University
      • Department of Nutrition, Food & Exercise Sciences
      Tallahassee, FL, United States
    • Mayo Clinic - Rochester
      Rochester, Minnesota, United States
  • 1997–2001
    • University of Virginia
      • • Division of Endocrinology and Metabolism
      • • Division of Maternal Fetal Medicine
      Charlottesville, VA, United States