Plasma Lipid, Glucose, and Immune Responses to Consumption of Nutritive and Nonnutritive Sweeteners and Exercise

Although nonnutritive sweeteners are widely used as substitutes for nutritive sweeteners, it is currently uncertain how these commonly available sweeteners affect plasma glucose and lipid metabolism. PURPOSE: To examine how nutritive and nonnutritive sweeteners influence plasma lipid profiles, complete blood counts, and plasma glucose content at rest and during exercise. METHODS: This randomized, double-blinded, cross-over design study included 9 healthy, college aged, individuals (4 females and 5 males). In four separate visits, participants consumed 8 oz of sweetened drink in random order with either 445mg of stevia, 507mg of aspartame, 169mg of sucralose, or 110,000mg of sucrose mixed into water. Each sweetened drink contained the equivalent to 3 sodas worth of sweetener. Participants had 2 minutes to consume each drink, then they rested in a chair for 30 minutes. At completion of 30 minutes of resting, participants completed a single bout of aerobic exercise on a cycle ergometer at 70% of HRmax for 45 minutes. Overnight fasting blood samples were collected at baseline, 30-min post-consumption of sweetened drink, and immediately post-exercise. RESULTS: At the 30-min post-consumption of the sweetened drink, plasma glucose level was significantly higher after consumption of sucrose (115.8 ± 6.14 mg/dL) than either sucralose (87.2 ± 7.09 mg/dL, p=.032) or stevia (86.1 ± 5.79 mg/dL, p=.010). However, the elevated plasma glucose level with sucrose was no longer significant immediately post-exercise. Following exercise, total cholesterol (TC), triglyceride (TG), and HDL-C were elevated (TC: 152.7 ± 9.66 to 158.6 ± 9.26 mg/dL, pCONCLUSIONS: A rise in plasma glucose 30-min post-consumption of sucrose, which returned to baseline levels post-exercise, indicates that the plasma glucose may have been used as a substrate during exercise. Nonnutritive sweeteners, however, likely had no effect on substrate utilization throughout exercise, since there was no significant change in plasma glucose from baseline through exercise. The decrease in lymphocytes, along with a rise in neutrophils, while still in their respective normal range, may suggest an acute immune response to sweetener consumption

Exercise Attenuated Plasma Oxidized Low-density Lipoprotein and Myeloperoxidase

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Effects of a Single Bout of Exercise on Lipoprotein Fractions in Hypercholesterolemic Women

Effects of a Single Bout of Exercise on Lipoprotein Fractions in Hypercholesterolemic Women Allen Sexton, Kavya Chelikani, and Yunsuk Koh Department of Health and Kinesiology, Lamar University, Beaumont, TX 77710 Classification of First Author: Master’s Background: Abnormal lipoprotein profiles are strongly associated with premature cardiovascular disease. Sedentary lifestyle and menopause may accelerate abnormal lipid and lipoprotein metabolism in women. A single bout of aerobic exercise at moderate intensity may positively alter serum lipoprotein fractions in postmenopausal women with high cholesterol levels. Objectives: The current study investigated how a single bout of exercise affects lipoprotein fractions in sedentary, postmenopausal women with hypercholesterolemia. Methods: Thirteen (N=13) sedentary, hypercholesterolemic (defined as total cholesterol \u3e 200 mg/dl; average TC = 241.7 ± 5.8 mg/dl) postmenopausal women (age = 57.4 ± 2.0 years) randomly performed both exercise and rest trials. For the exercise trial, participants performed a single bout of exercise at 60% of heart rate reserve on a treadmill until 400 kcal were expended. Serum samples were collected at pre (0), 24, and 48 hours following each trial to analyze the lipoprotein fractions (α, pre-β, and β) using electrophoresis. A 2 (trial: rest and exercise) x 3 (time: 0, 24, and 48 hours) repeated ANOVA was employed to determine the significant changes in serum lipoprotein fractions. The p value \u3c .05 was considered to be statistically significant. Results: The α-lipoprotein fraction in the exercise trial was significantly higher than the rest trial (35.7 vs. 34.9%, p=.006), while the β-lipoprotein fraction in the exercise trial was significantly lower than the rest trial (56.8 vs. 57.6%, p=.001). Additionally, the β-lipoprotein fraction at 24 hours (56.3%) was significantly lower (p=.008) than 0 (57.8%) or 48 hours (57.5%). The pre-β fraction remained unchanged. Conclusion: A single bout of moderate intensity aerobic exercise can favorably alter serum α- and β- lipoprotein fractions in postmenopausal women with hypercholesterolemia

Estimation of Visceral Fat via Ultrasound Sonography

Although visceral fat (VF) can be quantified via computed tomography or dual-energy X-ray absorptiometry (DXA), their application for frequent VF assessment is limited because both methods are radiating in nature. Research suggests that ultrasound imaging can be used to predict VF safely without the risk of radiation exposure. However, the complexity and/or lack of replicability limits such application. PURPOSE: To develop an easy-to-replicate ultrasound protocol and a regression model that can accurately estimate VF area (VFA, cm2). METHODS: Thirty healthy adults (9 males and 21 females, age: 23.2 ± 7.4 yr, body mass index: 22.3 ± 3.2 kg/m2, body fat percentage: 22.3 ± 5.9 %) fasted for 8 hours or more before a DXA scan and ultrasound imaging were performed to estimate VFA. Ultrasound imaging (with a 3.5-MHz convex-array probe) was used to measure the thickness of 15 different sites within the abdominal cavity. Thickness was defined as the distance in cm from the internal abdominal wall to the anterior aortic wall. Stepwise linear regression was utilized to develop a regression model for VFA using the estimated VFA by DXA as a dependent variable, followed by a Bland-Altman plot and Pearson correlation to compare the technique reliability. RESULTS: The developed regression model (F(4, 25) = 46.869, p = 0.001) was (37.677 + (1.456*Age) - (26.963*Sex) - (11.336*VFT2) + (13.554*VFT4)), where age = years, sex: 1 = male or 2 = female, and VFT2/4 = ultrasound probe placement 2 cm to the left (VFT2) and right (VFT4) of the superior umbilical border, respectively. The regression model had high accuracy (adjusted R2 = 0.864) and test reliability (r = 0.927, p = 0.001) at estimating VFA (31.4 ± 21.4 cm2) when compared to the VFA (31.1 ± 21.1 cm2) estimated by DEXA. CONCLUSION: Visceral fat area can be accurately estimated using an easy-to-replicate ultrasound protocol and regression model that eliminates the exposure to radiation caused by other body scanning methods

Role of High-intensity Resistance Exercise in Vascular Inflammation in Recreationally Trained Men

Soluble intracellular adhesion molecule-1 (sICAM-1) and soluble vascular cell adhesion molecule-1 (sVCAM-1) are known as vascular inflammatory markers and play a key role in the development of atherosclerosis. Although low to moderate intensity exercise may positively influence inflammatory markers, the role of high-intensity resistance exercise in sICAM-1 and sVCAM-1 has not been fully examined. The current study examined the effects of resistance exercise at different intensities (low vs. high) on acute responses of sICAM-1 and sVCAM-1. In a randomized, cross-over design, 10 recreationally trained (resistance-trained 3 to 6 days per week for at least one year) college-aged men performed a single bout of lower body resistance exercise, consisting of the leg press and unilateral knee extension exercises, at two different intensities (low intensity: 50% of 1-RM and high intensity: 80% of 1-RM). The volume of two intensities of exercise was similar. Overnight fasting blood samples were collected at baseline and 3-hr, 24-hr, and 48-hr post exercise (PE) for each exercise intensity to determine sICAM-1 and sVCAM-1. A 2 X 4 ANOVA with repeated measures was used to examine the mean differences in intensities and time on sICAM-1 and sVCAM-1, and the Least Significant Difference (LSD) tests were conducted as post hoc tests. If a significant interaction was found, the follow-up simple effects test was conducted. A p-value \u3c .05 was set for the statistical significance. Low-intensity resistance exercise did not significantly alter sICAM-1; however, during the high-intensity resistance exercise trial, sICAM-1 at 48-hr PE (364.85 ± 34.40 ng/ml) significantly (p = .037) decreased by 14.27% from 3-hr PE (425.60 ± 36.71 ng/ml). Following low-intensity resistance exercise, sVCAM-1 significantly (p = .001) increased by 27.6 % at 24-hr PE (p = .001) and remained elevated up to 48-hr PE (p = .001). In addition, sVCAM-1 at 24-hr PE (715.70 ± 38.14 ng/ml) and 48-hr PE (716.32 ± 34.79 ng/ml) for the low-intensity resistance exercise trial were significantly higher (p = .003 and p = .002, respectively) than the same time points of the high-intensity resistance exercise trial (24-hr PE: 532.57 ± 38.14 ng/ml and 48-hr PE: 533.18 ± 34.79 ng/ml). Thus, the current study suggests that high-intensity resistance exercise can also be an effective method to improve cardiovascular health since it reduced vascular inflammatory markers by decreasing sICAM-1 without altering sVCAM-1

Relationship of Cellular Adhesion Molecules and Stress Hormones in Obese Males Following Exercise

The development of atherosclerosis is associated with a steady accumulation of inflammatory molecules. Exercise-induced hormones such as cortisol and catecholamines (epinephrine and norepinephrine) may play a role in endothelial inflammation. Methods: Fifteen obese (BMI \u3e 30 kg/m2) sedentary (less than 2 days per week of physical activity) male volunteers, the ages between 18 and30, participated in the study. The participants performed a single bout of cycling exercise (average energy expenditure ~ 300 kcal) at two different intensities in random order [low-intensity: 50% of maximal heart rate and high-intensity: 80% of maximal heart rate]. Overnight fasting blood samples were collected at baseline, immediate post-exercise (IPE), 1-hr PE, and 24-hr PE for each intensity of exercise to determine the responses of soluble cell adhesion molecules [intercellular adhesion molecule-1 (sICAM-1), vascular cell adhesion molecule-1 (sVCAM-1), and E-selectin (sE-selectin)] and exercise-induced stress hormones. Data were analyzed by an analysis of variance with repeated measures along with the Bonferroni multiple comparisons. The linear regression analysis was used to examine the interaction between exercise-induced hormones and vascular inflammation markers (p \u3c .05). RESULTS: There exhibited no significant change in sICAM-1, sVCAM-1, E or NE, while sE-selectin at 1-hr PE (10.25±1.07 ng/mL) significantly decreased (p = .045) from baseline (12.22±1.39 ng/mL). COR at IPE (262.12±31.09 ng/ml) was significantly higher (p = .001) than 1-hr PE (189.35±31.11 ng/ml) during high-intensity exercise. In contrast, COR at IPE (187.52±31.09 ng/ml, p = .009) and 1-hr PE (156.24±31.11 ng/ml, p = .001) were significantly lower than baseline (259.75±23.07 ng/ml) during low-intensity exercise. COR and sICAM-1 had a negative relationship at 1-hr PE during low-intensity exercise (r2 = .34, p = .02), whereas COR and sVCAM-1 had a positive relationship at IPE during high-intensity exercise (r2 = .36, p = .02). CONCLUSION: sE-selectin was favorably reduced following exercise, and changes in cortisol were exercise-intensity dependent. Although sICAM-1 and sVCAM-1 did not significantly change following exercise, a significant interaction between cortisol and these cell adhesion molecules suggests that cortisol is one of the responsible exercise-induced hormones that may be associated with cell adhesion molecule metabolism

Changes in Creatine Phosphokinase Isoenzymes After Varying Levels of Resistance Exercise

Creatine phosphokinase (CK) isoenzymes are found in various tissues, such as skeletal muscle (CK-MM), cardiac muscle (CK-MB), and the brain (CK-BB). Elevated CK isoenzymes indicate damage or injury to specific tissue. Using CK isoenzymes as a marker in order to indicate muscle damage as a result of different degrees of resistance exercise has not been clearly examined. Purpose: To determine the changes in CK isoenzymes following resistance exercise at different intensities. Methods: Ten healthy recreationally resistance-trained (at least 3 - 6 days per week for a minimum of one year) men participated in the study. The participants performed a lower body resistance exercise, composed of leg press and unilateral knee extension, at two different intensities (low: 50% of 1-RM and high: 80% of 1-RM) in random order. The volume of two intensities was similar. Overnight fasting serum samples were collected at baseline and 3-hr, 24-hr, and 48-hr post exercise for each intensity to determine CK-MM, CK-MB, and CK-BB using electrophoresis. A 2 X 4 ANOVA with repeated measures was used to examine the mean differences in intensity and time on dependent variables. The Bonferroni pairwise comparisons were conducted to locate the significant mean differences. If a significant interaction was found, the follow-up simple effects test was conducted. A p-value \u3c .05 was set for the statistical significance. Results: There was no significant main effect for intensity or time on CK-MM, CK-MB, or CK-BB. However, the significant interaction between intensity and time indicated that CK-MM was significantly higher (93.00±4.03 vs. 86.39±4.15%, p = 0.002) and CK-MB was significantly lower (7.13±4.22 vs. 12.37±3.30%, p = 0.006) at 48-hr following the high-intensity exercise trial as compared with the same time point of low intensity exercise trial. Conclusion: An increase in CK-MM several days following high intensity resistance indicates potential skeletal muscle damage associated with high intensity resistance exercise. Interestingly, high intensity resistance exercise yields less cardiac muscle damage than low intensity resistance exercise in recreationally-trained men

Relationship Between Matrix Metalloproteinases and Tissue Inhibitor of Metalloproteinases Following High-fat Diet and Acute Exercise

Matrix metalloproteinases (MMPs) are involved in the degradation of the extracellular matrix of the tissue and inflammation. Several tissue inhibitors of MMPs (TIMPs) are known to inhibit the activity of MMPs. PURPOSE: The current study investigated the responses of MMP-1, -2, -9, and -10 and TIMP-1, -2, -3, and -4 after a 3-week high-fat, low-carbohydrate (HFLC) diet following an acute aerobic exercise. METHODS: Physically active (unprofessional, competitive marathon runners) male subjects (N=8, age= 39.5 ± 9.9 years) volunteered for the study. Subjects maintained their habitual high carbohydrate (HC) diets before switching to the HFLC diet (70% total caloric intake from fat, not exceeding 50 g of carbohydrates) for 3 weeks. Subjects performed an acute bout of aerobic exercise before and 24 hours after each HC and HFLC diet trial. The exercise protocol consisted of treadmill running at varying paces (personal race paces) for 50 minutes (split into 5, 10-minute periods with 2 minutes of rest in between). Following a 20-minute recovery, subjects additionally performed a 5-km time trial on an outdoor course. Overnight fasting blood samples were collected at pre- and 24-hours post-exercise for each diet trial to analyze changes in MMPs and TIMPs. The data were analyzed using an ANOVA [(HC and HFLC) X (pre- and post-exercise)]. If a significant interaction was found, a Tukey’s post-hoc test was performed (p \u3c 0.05). RESULTS: There was no significant difference in MMPs or TIMPs between the HC and HFLC diet trials, and an acute bout of aerobic exercise did not alter MMPs or TIMPs. There were, however, significant positive correlations between MMP-2 and TIMP-2 (r (14) = 0.51, p = 0.01) and MMP-9 and TIMP-2 (r (14) = 0.49, p = 0.01). Additionally, a significant negative correlation was found between TIMP-4 and MMP-4 (r (14) = -0.57, p = 0.02). CONCLUSION: A relatively short-term high-fat diet and an acute aerobic exercise did not influence serum MMPs or TIMPs in healthy, trained male runners. The activity of MMP-4 may be related to TIMP-4, while the activity of both MMP-2 and -9 may be dependent on TIMP-2. It is highly recommended that future studies focus on examining the effects of a long-term HFLC diet on metabolic pathways of circulating or tissue MMPs and TIMPs in a variety of populations

Effects of Dietary Fish-oil Supplement and Acute Eccentric Exercise on Inflammatory Markers during Different Phases of Menstrual Cycle

Fish-oil supplementation may play a positive role in inflammation. Matrix Metalloproteinases (MMPs) are important in controlling tumor growth, metastasis, angiogenesis, and inflammation. Several tissue inhibitors of MMPs (TIMPs) are known to regulate the activity of specific MMPs. PURPOSE: To examine the effects of dietary fish-oil supplementation and acute eccentric exercise on MMP-1, -2, -9, and -10 and TIMP-1, -2, -3, and -4 during two different phases of menstrual cycle. METHODS: As a randomized, double-blind, and placebo-controlled design, 22 college-aged women (age= 20.86 ± 1.39 years) were randomly assigned to either a fish oil (FOG, N=11) or a placebo group (PG, N=11). Participants in the FOG ingested 6 capsules of fish oil per day (total 6.0g, containing 2.4g eicosapentaenoic acid and 1.8g docosahexaenoic acid), while the PG took 6 capsules of safflower oil per day for 3 weeks. Participants in each group performed an acute bout of eccentric single-leg exercise (10 sets of 10 repetitions with a 3-min rest between sets at an isokinetic speed of 30⁰/second) during the mid-follicular (MF) and mid-luteal (ML) phases. The leg exercised for the MF phase was randomly selected and the opposing leg exercised during the ML phase. Overnight blood samples were collected at baseline, 6-hr post-exercise (6hr-PE), and 24-hr PE during the MF and ML phases. Data were analyzed by a separate 2 x 2 x 3 ANOVA with repeated measures along with an appropriate post-hoc test for any significant interactions (p \u3c 0.05). RESULTS: A significant interaction effect (p=0.005) in MMP-1 indicated that MMP-1 in the FOG (193.71±21.72 pg/mL) was higher than that of the placebo group (120.79±21.72 pg/mL) during the MF phase. Both TIMP-1 and -3 were significantly higher (p=.043 and p=.037, respectively) in the FOG (68674.71±2238.56 and 3827.12±193.67 pg/mL, respectively) than the placebo group (62119.26±2178.86 and 3238.94±186.73 pg/mL, respectively). CONCLUSION: Acute eccentric exercise did not affect MMPs and TIMPs in healthy, young females. MMP-1 was the only proteinase affected by the menstrual cycle and a decrease in MMP-1 during the ML phase might be related to elevated estradiol levels. Elevated TIMP-1 and -3 following the 3-weeks of fish-oil supplementation suggested a potential anti-inflammatory effect of the fish-oil supplementation by inhibiting activation of MMPs. It is recommended that an extended period of fish oil supplementation be implemented to further examine its anti-inflammatory effect on other inflammatory biomarkers in different sample groups including both pre- and post-menopausal women

The Role of University-Required Fitness Courses in Students\u27 Health and Exercise Practices

Lifetime fitness (LF) classes include exercise, sport, and recreational activity courses. The main purposes of LF classes are to give health education that elicits mental, social, and physical preparation for a lifelong experience of fitness. However, previous research has not extensively investigated the role of LF classes on students’ motivations to exercise during and after completing the course. PURPOSE: To determine whether or not taking an LF class contributes to a student’s motivation to exercise, to determine a motivation for signing up for an LF course, to determine why they chose that specific class, and to determine the degree to which an LF class effectively changes a student’s view on exercise. METHODS: Male and female college students (n=183) were recruited from LF classes, including aerobic walking, aerobic running, volleyball, softball, strength training, golf, bowling, and fitness theory. At the beginning of the semester, a survey was given via Qualtrics that asked four open-ended questions about the students’ views of LF classes. RESULTS: In response to the first question, “Why did you choose this LF course?”, 30% of the students responded it was to play a fun sport. Other responses included to maintain a healthy lifestyle (15%), to continue to play a sport they played before the LF class (17%), or to learn how to play a new sport (17%). The second question asked, “Why are you taking an LF course?”, and 87% of the students responded it was required. The other 13% responded they took it for fun, or they wanted to take it with a friend. The third question asked, “Why do you think Baylor requires you to take an LF class?”. 86% of the students felt that Baylor requires LF classes for the well-being of students, while 14% were not sure why or believed it was for monetary purposes. The final question asked, “What is your motivation for exercising, both in an LF and outside of class?” To this question, 98% of participants responded saying their motivation was to maintain health or for fun, social reasons. The other 2% responded saying their motivation was a GPA boost. CONCLUSIONS: When asked why students are taking an LF class, the majority of students indicated they did so for reasons from a negative approach. However, when asked about exercise motivation as a whole, the majority of the students indicated reasons for wanting to exercise from a positive approach. The disparity between answers given for these two questions may indicate a motivational distinction between LF classes and exercise in general. Therefore, further research exploring the intrinsic and extrinsic motivations between exercise and LF classes is warranted