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A-37 Free Communication/Poster - Clinical Exercise Physiology-Diabetes (Clinical Exercise Physiology Association)

Medicine & Science in Sports & Exercise: May 2013 - Volume 45 - Issue 5S - p 40–43
doi: 10.1249/01.mss.0000433612.20932.a0

May 29, 2013, 7:30 AM - 12:30 PM

Room: Hall C

218 Board #70 May 29, 11:00 AM - 12:30 PM

Associations of Insulin Resistance with Metabolic Syndrome Risk Factors in Young, Hispanic Women

Katrina Taylor, Chantal A. Vella. University of Idaho, Moscow, ID. (Sponsor: Dan Heil, FACSM)

(No relationships reported)

Approximately 65% of Hispanic women aged 20-39 years are overweight or obese. As Hispanic women age from 12-19 years to 20-39 years the prevalence of overweight and obesity increases from 42% to 65%. Concurrent with this rise in overweight and obesity is an increase in risk of the metabolic syndrome, a precursor to cardiovascular disease. The reasons for this are unknown but may be related to the development of central obesity and insulin resistance in young Hispanic women.

PURPOSE: To determine the associations between insulin resistance and metabolic syndrome risk factors in young Hispanic women.

METHODS: 131 Hispanic women (mean ± SD: age 25.0 ± 5.0 y; BMI 22.8 ± 3.1 kgm2; body fat 31.8 ± 6.9 %) participated in the study. Metabolic syndrome risk factors measured were waist circumference, fasting glucose, triglycerides (TG), high-density lipoprotein cholesterol (HDL), and systolic (SBP) and diastolic (DBP) blood pressure. Markers of insulin resistance included homeostasis model assessment (HOMA) and fasting insulin. Pearson product-moment correlation analyses were used to assess associations between variables with alpha level set at 0.05.

RESULTS: The majority of participants were normal weight (86%) with only 14% overweight or obese, based on BMI. Prevalence of 1, 2, or 3 or more risk factors was 39%, 14%, and 3%, respectively. Fifty six percent of women had at least one metabolic syndrome risk factor and only 44% were risk factor free. The most prevalent risk factor in this sample was a low HDL with 40% of women exhibiting this risk factor. HOMA and fasting insulin were positively and significantly (p < 0.01) related to waist circumference (r = 0.53 and r = 0.54), TG (r = 0.29 and r =0 .30), SBP (r = 0.25 and r = 0.28) and DBP (r = 0.24 and r = 0.25), respectively, and significantly (p < 0.05) and negatively associated with HDL (r = -0.25 and r = -0.21, respectively).

CONCLUSIONS: 56% of women had at least one metabolic syndrome risk factor and 17% had two or more risk factors. HOMA and fasting insulin were associated with individual metabolic syndrome risk factors and may be important clinical markers for identifying Hispanic women at-risk for developing metabolic syndrome. These findings highlight the importance of prevention efforts in normal-weight and overweight young, Hispanic women. Supported by NIH NIDDK 1SC2DK083061.

219 Board #71 May 29, 11:00 AM - 12:30 PM

Factors Associated with Diabetes Risk in South Texas College Students

Jordan Stack, Christine Brumley, Mansi Parikh, Adley Canales, Sara E. Mahoney, Christopher M. Hearon, FACSM. Texas A&M University - Kingsville, Kingsville, TX.

(No relationships reported)

South Texas has a high prevalence of diabetes and college students may be particularly at risk for developing diabetes. Early detection and prevention are crucial to reducing the prevalence of this disease. While increased BMI, sedentary activity and depression have been associated with diabetes progression in the general population, it has not been established whether these factors contribute to increased risk for developing diabetes in college students.

PURPOSE: To assess diabetes risk and to determine whether depressive symptoms or physical activity patterns are associated with increased diabetes risk in college students.

METHODS: 69 college students were assessed for diabetes risk using the Finnish Diabetes Risk Score (FINDRISC) questionnaire. Each subject also completed the International Physical Activity Questionnaire (IPAQ) long form which includes a sitting subscale, the Zung Self-Rated Depression Scale and had anthropometric measures taken. Relationships were determined using Pearson Product Movement correlation, α=0.05.

RESULTS: 21.7% of students reported an elevated risk (FINDRISC score 7-11), and 4.3% of subjects had a moderate to high risk of developing diabetes (FINDRISC >12). On average, the sample of students were overweight (BMI = 26.81±0.75 kg . m-2), and BMI was associated with diabetes risk (r = 0.626, p = 0.001). While diabetes risk was not correlated with the IPAQ total physical activity score (r = 0.019, p = 0.874), it had a modest correlation with time spent sitting (r = 0.295, p = 0.015). There was no association between self-reported depressive symptoms and diabetes risk (r =0.078, p = 0.525).

CONCLUSION: A substantial number of college students in South Texas are at risk for developing diabetes. Although diabetes risk was not associated with total physical activity and depressive symptoms, it was associated with time spent sitting and BMI. This suggests that in this college-age population, sitting less and reducing weight may help lower the risk of developing diabetes.

220 Board #72 May 29, 11:00 AM - 12:30 PM

Sedentary Behavior, Central Obesity And Cardiovascular Disease Risk Factors In Young Women

Amber N. Green, David R. Paul, Ryan P. McGrath, Vanessa Martinez, Katrina Taylor, Chantal A. Vella. University of Idaho, Moscow, ID. (Sponsor: Dan Heil, FACSM)

(No relationships reported)

Recent data suggest nearly a 2-fold increase in the prevalence of overweight and obesity as women age from adolescence to young adulthood, such that 56% of young women are overweight or obese. Concurrent with this rise in obesity is an increased risk of cardiovascular disease (CVD). The reasons for the increased risk of CVD are unknown but may be related to the time spent in sedentary behaviors and the development of central obesity.

PURPOSE: To investigate the associations between sedentary behaviors and central obesity, and the individual CVD risk factors in young women. We also investigated whether these associations were independent of body composition.

METHODS: 38 women (mean ± SD: age 24.4 ± 5.0 y; BMI 26.3 ± 5.3 kgm2; body fat 32.1 ± 7.2%) participated in the study. CVD risk factors measured were fasting glucose, triglycerides (TG), high-density lipoprotein, low density lipoprotein, and systolic and diastolic blood pressure. Body composition and central obesity were estimated by BodPod and waist circumference, respectively. Sedentary behavior, measured by 7 days of accelerometer wear, was defined as <100 counts/min and data were analyzed as mean min/day. Simple and multiple regression analyses were used to assess associations between variables. Regression models were adjusted for body composition by including body fat mass and fat free mass as covariates. Alpha level was set at 0.05.

RESULTS: Time spent in sedentary behaviors averaged 1037.3 ± 92.7 min/day and waist circumference averaged 88.6 ± 10.8 cm. Time spent in sedentary behaviors was positively and significantly related to TG (r = 0.418, p = 0.009) and this relationship was independent of body composition (Beta = 0.362, p = 0.036). Time spent in sedentary behaviors was not related to other CVD risk factors (p > 0.05). Waist circumference was positively and significantly related to TG (r = 0.392, p = 0.015) and glucose (r = 0.323, p = 0.048) but these relationships were not independent of body composition (p > 0.05).

CONCLUSIONS: Sedentary behavior and central obesity were associated with individual CVD risk factors in young women. These findings have important implications for CVD prevention programs for young women and suggest that public health guidelines with regards to minimizing sedentary behaviors are warranted. Supported by University of Idaho Seed Grant.

221 Board #73 May 29, 11:00 AM - 12:30 PM

Effects Of Aerobic And Resistance Exercise Training On RMR In Elderly Women With Diabetes

Soon-Mi Choi1, Ji-Wan Yoon2, Yae-Young Kim3, Man-Gyoon Lee3, Soo Lim2. 1Texas A&M International University, Laredo, TX. 2Seoul National University Bundang Hospital, Seongnam, Republic of Korea. 3Kyung Hee University, Yongin, Republic of Korea.

(No relationships reported)

Aerobic exercise is important for prevention and management of type 2 diabetes (T2D). Resistance exercise also has been reported to be beneficial for T2D patients.

PURPOSE: This study examined the effects of 12 weeks of aerobic or resistance exercise on body composition, aerobic capacity, muscular strength, resting metabolic rate (RMR), and RMR-related blood variables.

METHODS: Thirty-six Korean female T2D patients, aged 69.3±5.6 yrs, were randomly assigned into three groups, i.e., aerobic training group (AT; n=13), resistance

training group (RT; n=13), and control group (CON; n=10). Subjects in training groups performed the assigned exercise at 60-70% of HRmax or 1RM, 20-40 min/session, and 3 sessions/wk for 12 weeks, whereas subjects in CON maintained their normal life patterns. Body composition, aerobic capacity, muscular strength, RMR, and RMR-related blood variables were measured pre- and post-intervention, and the results were analyzed utilizing a repeated measures two-way ANOVA.

RESULTS: Body weight, body mass index, and waist circumference decreased significantly (P<0.05) in AT, and hip circumference decreased significantly (P<0.001) in both AT and RT. Fat mass and percent body fat decreased in AT (P<0.001) and RT (P<0.01). Fat-free mass increased significantly in RT (36.0±3.6 to 36.7±3.4 kg, P<0.01) and AT (37.3±3.7 to 37.7±3.4 kg, P<0.05). VO2max increased significantly (P<0.05) in both AT and RT. One-RM for seated row and leg press but not bench press increased significantly in RT (P<0.001). RMR increased significantly in RT (0.69±0.23 to 0.79±0.23 kcal/min, Δ% = 19.09%, P<0.05). Epinephrine in AT and thyroid stimulating hormone in RT decreased significantly (P<0.01). Fasting glucose (126.4±25.1 to 105.9±16.6 mg/dl) and total cholesterol (189.2±32.8 to 158.9±33.9 mg/dl) decreased significantly (P<0.01) in the AT.

CONCLUSIONS: Both AT and RT were effective in reducing body fat mass in elderly T2D patients. AT was more beneficial in improving fasting glucose and total cholesterol, whereas RT resulted in an increased RMR (perhaps due to favorable adaptations in FFM) which may be beneficial in the long-term. These results provide meaningful information for developing specific exercise programs for elderly T2D patients.

222 Board #74 May 29, 11:00 AM - 12:30 PM

Non-response of Peak Exercise Oxygen Consumption in Response to Exercise Training in Type 2 Diabetes

Damon L. Swift1, Neil M. Johannsen2, Conrad P. Earnest, FACSM3, Carl J. Lavie4, Timothy S. Church5. 1Pennington Biomedical Research Center, Charlottesville, LA. 2Louisiana State University, Baton Rouge, LA. 3University of Bath, Bath, United Kingdom. 4John Ochsner Heart and Vascular Institute Ochsner Clinical School - The University of Queensland School of Medicine, New Orleans, LA. 5Pennington Biomedical Research Center, Baton Rogue, LA.

(No relationships reported)

Despite participating in aerobic training, a proportion of individuals do not increase cardiorespiratory fitness (CRF) as assessed by peak oxygen consumption (peak VO2). However, non-response has not been specifically investigated in individuals with type 2 diabetes (T2D). In addition, no data exists regarding the training responses in other cardiovascular disease (CVD) risk factors in individuals who do not improve peak VO2 with exercise training.

PURPOSE: To evaluate the prevalence of non-response to peak VO2 following aerobic alone or a combination of aerobic training and resistance training in men and women with T2D. We also investigated the changes in cardiometabolic and glucose control measures in individuals who did not improve peak VO2 following aerobic training.

METHODS: A subset of men and women (n=81) from the Health Benefits of Aerobic and Resistance Training in Type 2 Diabetes (HART-D) study performed a maximal treadmill test at baseline and following 9 months of exercise training. Participants were categorized by the change in absolute peak VO2 (Response: >0 L/min, Non-Response: ≤ 0 L/min). Analysis of covariance was used to evaluate the change in cardiometabolic risk factors in participants who did not increase peak VO2 following training with adjustments for baseline value and randomization group.

RESULTS: Following exercise training, 36.6% and 40.0% did not increase peak VO2 in the aerobic and combination groups respectively. However, these individuals had significant reductions in body weight (-1.3 kg, CI: -2.3, -0.3), waist circumference (-2.4 cm, CI: -3.7, -1.0), hemoglobin A1C (-0.28%, CI: -0.45, -0.11), and systolic blood pressure (-5.6 mmHg, CI: -9.3, -1.9), and a significant increase in estimated metabolic equivalents (METs) (0.54 METs, CI: 0.2, 0.9) following aerobic training.

CONCLUSIONS: Non-response to peak VO2 is present in nearly 40% individuals with T2D following aerobic training; however, significant improvements in glucose control and other cardiometabolic variables were observed. Although, non-responders did not increase CRF when defined by peak VO2 (generally considered the gold standard for assessment of CRF), improvements in maximal estimated METs were observed, which are associated with marked reductions in CVD and mortality risk in epidemiological studies.

223 Board #75 May 29, 11:00 AM - 12:30 PM

The Aerobic Exercise Reduces Cellular Stresses Related To Muscle Insulin Resistance In Obese Humans

Flávio C. Magalhães1, Mariana A. Matos1, Vinicius O. Ottone1, Paula F. Aguiar1, Pâmela Fiche1, Tamiris Duarte1, Karine Costa1, Suzanne Schneider2, Pope Moseley2, Cândido C. Coimbra3, Etel Rocha-Vieira1, Fabiano T. Amorim1. 1Federal University of the Jequitinhonha and Mucuri Valleys, Diamantina, Brazil. 2University of New Mexico, Albuquerque, NM. 3Federal University of Minas Gerais, Belo Horizonte, Brazil.

(No relationships reported)

PURPOSE: In obesity, the activation of the c-Jun N-terminal kinase (JNK) may trigger the phosphorylation of insulin receptor substrate (IRS) on serine residues resulting in insulin resistance. Recent evidences suggest that increase or overexpression of heat shock protein 70 (Hsp70) may protect against insulin resistance, probably inhibiting JNK activation. However, it is not known if one session of aerobic exercise, which can increase insulin sensitivity, may induce expression of Hsp70 in skeletal muscle and reduce the activation of JNK and phosphorylation of IRS on serine residues of insulin resistant obese subjects. This study aimed to evaluate the effects of one aerobic exercise session on the activation of JNK, phosphorilation of IRS-1 ser612 and expression of Hsp70 in skeletal muscle of insulin-resistant obese subjects.

METHODS: 27 subjects were divided into three groups according to their body mass index and presence of insulin resistance (defined by the homeostatic model assessment/HOMA-IR): eutrophic (CON), obese insulin-sensitive (OB) or obese insulin-resistant (OBR). The volunteers performed 60 minutes of aerobic exercise on a cycle ergometer at 60% of peak oxygen consumption. Skeletal muscle biopsy of the vastus lateralis was performed before and after the exercise session. The proteins expressions were evaluated by western blot.

RESULTS: At baseline, JNK1/2 activation was dependent on obesity and insulin resistance (OBR>OB>CON or 460 ± 107%, 218 ± 67%, and 100 ± 23%, respectively, p<0.05). After exercise, a reduction in JNK1/2 activation was only observed in OBR (460 ± 328% versus 107% ± 33, OBR and OB respectively, p<0.05). At baseline, IRS-1ser612 depended on obesity but not on insulin resistance (OBR = OB > CON, p<0.05). Exercise reduced IRS-1 ser612 in both OBR (312 ± 73 versus 185% ± 36%) and OB (340 ± 67 versus 122% ± 44%, p<0.05). At baseline, OBR (46 ± 5%) and OB (63 ± 12%) groups had reduced Hsp70 expression, and this expression was depended on obesity and insulin resistance (OBR < OB < CON, p<0,05). We observed a main effect of exercise on Hsp70 in all groups (p<0.05).

CONCLUSION: One exercise session was able to reduce skeletal muscle cellular stress and increase Hsp70 expression in insulin-resistant obese individuals.

224 Board #76 May 29, 11:00 AM - 12:30 PM

The Integrated Effects Of Anaerobic Exercise And/or Vanadyl Sulfate Interventions In Streptozotocin-diabetic Rats

Wu Hao, Li Jianbing. Capital University of Physical Education and Sports, Beijing, China.

(No relationships reported)

PURPOSE: This study was designed to assess the impact of Vanadyl Sulfate supplement,anaerobic exercise on blood variables of Streptozotocin-diabetic rats (SDR).

METHODS: 40 male Wister rats with a mean initial body weight of 195±10g were used for this study. Diabetes was induced after an 18-hour fast by one time injection of streptozotocin 55mg/kg, The all SDR were divided into 4 subgroups for 6 weeks after induction of diabetes, they are sedentary (D), anaerobic exercise(R), Vanadyl Sulfate (DV, 1.25mg/ml) in drink water, and R with DV, The normal rats were randomly distributed into sedentary (N) at the same time. Glucose concentration in the tail blood of rats were assessed before, 24 hours later and every 2 weeks. Other blood parameters including insulin, free C peptide, Glucagons, blood lactate in OGTT (Oral glucose tolerance test) etc.

RESULTS:At the end of 6-week supplementation program. The integrated effects of Vanadyl Sulfate with anaerobic exercise interventions reduced fasting glucose was found in intervention group (10.28±3.89 vs.19.06±1.09 mmol/L,P<0.01), significantly reduce the sustained hyperglycemia and the area below the OGTT glucose curve (56.95±15.41 vs.98.06±4.42,P<0.05).

CONCLUSIONS: the study found that Vanadyl Sulfate treatment with anaerobic exercise could reduce diabetic syndrome more than others, and achieve a significant therapeutic effects on SDR. The safety and effect of Vanadyl Sulfate with anaerobic exercise for human diabetes need the further researches.

225 Board #77 May 29, 11:00 AM - 12:30 PM

Acute Isoenergetic Moderate- And High-intensity Exercise Improve Insulin Action In Pre-diabetic Adults

Corey A. Rynders1, Judy Y. Weltman2, Boyi Jiang2, Marc Breton2, Eugene J. Barrett2, Arthur Weltman, FACSM2. 1Old Dominion University, Norfolk, VA. 2University of Virginia, Charlottesville, VA.

(No relationships reported)

PURPOSE:We examined the effects of acute isoenergetic moderate (MIE) and high intensity (HIE) exercise on insulin action in seventeen sedentary pre-diabetic adults (8 males/9 females; age=49yrs; BMI=32.4 kg/m2; fasting glucose=106 mg/dl; 2-hour glucose= 173 mg/dl; A1c= 5.7%).

METHODS:Subjects completed 3 conditions with order randomized: MIE (50% VO2peak), HIE (82% VO2peak), and seated rest (Control). Exercise energy expenditure was equated to 200-kCal. One-hour post-exercise (or control), subjects received a 3-hr, 75-gram oral glucose tolerance test (OGTT). Plasma glucose and insulin concentrations were measured before and at frequent intervals after glucose ingestion. The oral minimal model, which incorporates the plasma glucose and insulin response observed during the OGTT and the glucose dose were used to derive insulin sensitivity (SI).

RESULTS:Compared to control, insulin sensitivity was increased by 22% (p = 0.04) and 30% (p = 0.002) after MIE and HIE, respectively. There were no differences in SI between the exercise conditions (p=0.36). The improvement in insulin action corresponded to reductions in the incremental area under the curve (AUC) for glucose previously reported by our group [compared to control 3-hr glucose AUC decreased by 13.9% (p=0.03) and 21.4% (p<0.001) after MIE and HIE, respectively].

CONCLUSIONS: These results demonstrate that changes in SI occur early in the recovery period after a single bout of exercise (at least 1-hour after the cessation of exercise) and that when calorically equated, both moderate and high intensity exercise are effective for improving SI in pre-diabetic adults.

226 Board #78 May 29, 11:00 AM - 12:30 PM

Aerobic Power And Capacity Predict Changes In Insulin Action After Acute Exercise In Pre-diabetic Adults

Arthur Weltman, FACSM1, Corey A. Rynders2, Judy Weltman1, Boyi Jiang1, Marc Breton1, Eugene Barrett1. 1University of Virginia, Charlottesville, VA. 2Old Dominion University, Norfolk, VA.

(No relationships reported)

PURPOSE:We previously reported that when exercise is calorically equated, both acute moderate (MIE) and high intensity exercise (HIE) improve insulin sensitivity in pre-diabetic adults. However, there is considerable variation in the insulin sensitizing effects of exercise as some subjects respond more favorably to MIE whereas others respond more favorably to HIE. The present study examined body composition, the lactate threshold (VO2LT), and peak oxygen consumption (VO2peak) as possible correlates of post-exercise changes in insulin action after acute isoenergetic MIE and HIE.

METHODS:Pre-diabetic subjects completed a VO2peak/LT protocol plus 3 randomly assigned conditions: MIE (50% VO2peak), HIE (82% VO2peak), and seated rest (Control). Exercise energy expenditure was equated to 200-kCal. One-hour post-exercise (or control), subjects received a 3-hr, 75-gram oral glucose tolerance test (OGTT). Insulin sensitivity (SI) was derived from minimal model fitting of plasma glucose and insulin concentrations measured at frequent intervals during the OGTT. Exercise induced changes in SI (ΔSI-MIE; ΔSI-HIE) were expressed relative to the control condition. Pearson correlation analysis was performed to examine the relationship between ΔSI and potential predictor variables [body mass, percent body fat (%BF), fat-mass (FM), lean-mass (FFM), VO2peak, and VO2LT].

RESULTS:Body composition was not related to ΔSI-MIE (range of r-values: -0.16 to -0.47, range of p-values: 0.06 to 0.54). %BF and FFM correlated with ΔSI-HIE (%BF: r= -0.53, p=0.03; LM: r=0.52, p=0.03). VO2LT was significantly correlated with ΔSI-MIE (r=0.67; p=0.003) and ΔSI-HIE (r=0.57; p=0.02). VO2peak was related to ΔSI-HIE (r=0.56, p=0.02), but not to ΔSI-MIE (r=0.24, p=0.35). The relationship of VO2LT and VO2peak to ΔSI persisted after statistical control for FFM (range of partial-r values: 0.45 to 0.67, P =0.004 to 0.08). Correlations between body composition and ΔSI-HIE were no longer significant after statistical control for VO2peak.

CONCLUSIONS:These data highlight the importance of the LT and VO2peak as determinants insulin action after acute isoenergetic moderate and high intensity exercise and suggest LT and VO2peak are stronger determinants of SI than body composition in pre-diabetic adults.

227 Board #79 May 29, 11:00 AM - 12:30 PM

Influences of Vascular Restriction on the Obese Female Substrate Utilization

Lesly I. Flores, Sonio D. Garcia, Benjamin Alaniz, Guillermo Perez, Murat Karabulut. University of Texas at Brownsville, Brownsville, TX.

(No relationships reported)

Increase in exercise intensity increases the dependence of substrate utilization (RER) from fat to carbohydrates. Even though moderate to vigorous intensity exercise promotes greater health benefits in the cardiorespiratory system, obese populations find engaging in physical activity a challenge due to an increased risk in injuries and strain put onto the body. Vascular restriction (VR), a training technique that decreases mechanical load, mimics moderate to vigorous intensity exercises while using lower load and/or intensity. It is plausible that because VR alters intensity, there can be changes in RER, oxygen consumption (O2 C), and carbon dioxide production (CO2 P) during low intensity exercise.

PURPOSE: To investigate the acute effects of different initial restrictive pressures (IRP) on RER, O2 C, and CO2P in the obese female at a constant cycling load.

METHODS: Eight sedentary female (age=22.8(0.9); BMI=35.4 (1.3)) subjects visited the lab on three different occasions and completed the appropriate documentation. Participants were attached to a metabolic cart that was calibrated according to the manufacturer’s guidelines. The randomized sessions were separated by 24-48 hours and consisted of a nonvascular restriction (CON) and two different IRPs of 40-45 mmHg and 60-65 mmHg with the VR cuffs positioned over the inguinal region of the thigh. Subjects performed two ten-minute bouts on the cycle-ergometer set at 50 rpm and 1kp, separated by a one-minute rest interval.

RESULTS: There was a significant time effect for RER, O2 C, and CO2 P (p< 0.05), however no significant condition main effect was observed for any of the aforementioned variables tested. There was a trend for condition main effect for CO2

P (p= 0.09) indicating that there might be VR-induced increases in CO2 P.

CONCLUSIONS: The trend seen for CO2 P indicates that changes in substrate utilization may happen over time or when higher IRPs are used. The rationale for not seeing any significant differences in substrate utilization could be due to females having a greater amount of subcutaneous fat accumulated around the thighs. IRPs used in this study might not be high enough for the female population; therefore future studies should investigate the effects of subcutaneous fat on various IRPs and substrate utilization.

228 Board #80 May 29, 11:00 AM - 12:30 PM

The Effect Of 10- Versus 30-minutes Of Acute Aerobic Exercise On Insulin And Glucose In Obese Adults

Anne E. Mishler1, Bethany Barone Gibbs2, Brett Goodpaster2, Elizabeth Nagle2, Lori Portzer2, Jackson Coppock2. 1Mercyhurst University, Erie, PA. 2University of Pittsburgh, Pittsburgh, PA.

(No relationships reported)

Obesity is associated with insulin resistance often accompanied by hyperinsulinemia and hyperglycemia, placing obese individuals at risk for type 2 diabetes and other chronic diseases. Acute exercise is associated with a decrease in postprandial insulin and glucose, but it is unknown how exercise of varying duration affects these variables.

PURPOSE: The purpose of this study was to compare changes in postprandial insulin and glucose following 10-minutes (10-EX) and 30-minutes (30-EX) of aerobic exercise to a resting (REST) condition.

METHODS: 9 healthy, sedentary obese men and women (BMI: 33.6±3.2 kg/m2; Age: 45.3±5.7 years) each performed 10-EX, 30-EX and REST in a randomized fashion. Blood was collected in the fasting state, and at 30-minute intervals following breakfast for 120-minutes. All exercise sessions were performed at 70-75% maximal heart rate.

RESULTS: Data was collected at all time points for five subjects, which were included in area under the curve (AUC) analyses. There was no significant difference in plasma insulin AUC between REST (12,270±6,148), 10-EX (10,633±5,162), and 30-EX (11,479±4,810) (p=0.354). There was no significant difference in plasma glucose AUC between REST (23,184±6,023), 10-EX (21,735±2,680), and 30-EX (22,899±3,328) (p=0.554). However, the patterns of change were not consistent across experimental conditions. A significant main effect for condition (p=0.018) was detected at 60-MIN for insulin, with lower insulin observed in 30-EX (32.3±12.3) compared to 10-EX (66.8±30.3) or REST (94.9±48.0). Insulin rebounded following exercise and was significantly higher at 120-MIN in 30-EX (74.3±45.2) compared to REST (55.4±45.7) (p=0.042). Plasma glucose followed a similar pattern, and a significant main effect was observed at 90-MIN (p=0.037), and was elevated in 30-EX (147.6±29.0) compared to 10-EX (122.2±21.5) or REST (121.4±38.0).

CONCLUSION: There was no significant difference in plasma insulin or glucose AUC between 10-EX, 30-EX and REST, but pattern of change was not consistent across conditions. Additional research should explore if differences in pattern of change following 10- or 30-minutes of exercise affect health outcomes in obese adults.

© 2013 American College of Sports Medicine