Biomedical subjects

Alan C Utter

Publications and source records attributed to Alan C Utter.

At least 19 recordsLinked to original sources

PubMed2006

Ibuprofen use, endotoxemia, inflammation, and plasma cytokines during ultramarathon competition.

The primary purpose of this study was to measure the influence of ibuprofen use during the 160-km Western States Endurance Run on endotoxemia, inflammation, and plasma cytokines. Subjects included 29 ultramarathoners who consumed 600 and 1200 mg ibuprofen the day before and on race day, respectively, and 25 controls that competed in the race but avoided ibuprofen and all other medications. Blood and urine samples were collected the morning prior to and immediately following the race, and subjects recorded muscle soreness during the week following the race using a 10-point Likert scale (DOMS). Race time (25.8+/-.6 and 25.6+/-.8 h, respectively) and ratings of perceived exertion (RPE, 6-20 scale) (14.6+/-.4 and 14.5+/-.2, respectively) did not differ significantly between ibuprofen users and nonusers. Ibuprofen use compared to nonuse was linked to a smaller increase in urine creatinine (P=.038), higher plasma levels of lipopolysaccharide (group effect, P=.042), and greater increases (pre-to-post race) in serum C-reactive protein and plasma cytokine levels for interleukin (IL)-6, IL-10, IL-8, IL-1 ra, granulocyte colony-stimulating factor, monocyte chemotactic protein 1, and macrophage inflammatory protein 1 beta, but not tumor necrosis factor alpha. Post-race DOMS and serum creatine kinase levels did not differ significantly between ibuprofen users and nonusers (20,621+/-3565 and 13,886+/-3068 microcal/L, respectively, P=.163). In conclusion, ibuprofen use compared to nonuse by athletes competing in a 160-km race did not alter muscle damage or soreness, and was related to elevated indicators of endotoxemia and inflammation.

Adult↗

PubMed2006

Blood leukocyte mRNA expression for IL-10, IL-1Ra, and IL-8, but not IL-6, increases after exercise.

The primary purpose of this project was to study exercise-induced leukocyte cytokine mRNA expression. Changes in plasma cytokine levels and blood leukocyte mRNA expression for interleukin-6 (IL-6), IL-8, IL- 10, and IL-1 receptor antagonist (IL-1Ra) were measured in 12 athletes following 2 h of intensive cycling ( approximately 64% Watts(max)) while ingesting a carbohydrate or placebo beverage (randomized and double blinded). Blood samples were collected 30 min preexercise and immediately and 1 h postexercise. Carbohydate compared with placebo ingestion attenuated exercise-induced changes in plasma cortisol (8.8% vs. 62%, respectively), epinephrine (-9.2% vs. 138%), IL-6 (10-fold vs. 40-fold), IL-10 (8.9-fold vs. 26-fold, and IL-1Ra (2.1-fold vs. 5.6-fold). Significant time effects were measured for blood leukocyte IL-8 (2.4-fold increase 1 h postexercise), IL-10 (2.7-fold increase), IL-1Ra (2.2-fold increase), and IL-6 (0.8-fold decrease) mRNA content, with no significant differences between Cho and Pla test conditions. In summary, gene expression for IL-8, IL-10, and IL-1Ra, but not IL-6, is increased in blood leukocytes taken from athletes following 2 h of intensive cycling and is not influenced by carbohydrate compared with placebo ingestion. mRNA expression was high enough to indicate a substantial contribution of blood leukocytes to plasma levels of IL-8, IL-10, and IL-1Ra during prolonged exercise.

Adult↗

PubMed2006

Validation of Omni scale of perceived exertion during prolonged cycling.

PURPOSE: The present investigation was conducted to validate the OMNI ratings of perceived exertion (RPE) scale during prolonged cycle exercise when subjects were supplemented with either carbohydrate or placebo. METHODS: Fifteen trained cyclists cycled for 2.5 h at approximately 60% maximal watts on two occasions while receiving 4 mL x kg(-1) x 15 min(-1) carbohydrate (6%) (C) or placebo (P) beverages in a randomized, counterbalanced design. Concurrent and construct validity was established by evaluating perceptual responses with both the OMNI and Borg RPE scales every 20 min throughout the trials. RESULTS: The pattern of change in RPE over time was significantly different between C and P ingestion (P < 0.05), with an attenuated RPE response in C found at the hundredth minute for both the OMNI and Borg scales. The pattern of change in the respiratory exchange ratio and carbohydrate oxidation rates were significantly greater (P < 0.001) in the C than P condition. RPE-OMNI was positively and linearly related to the RPE-BORG; r = 0.60-0.98 (P < 0.01) throughout exercise for both the C and P conditions. CONCLUSIONS: Concurrent and construct evidence supports the use of the OMNI-cycle scale by adult men to estimate RPE during prolonged cycle exercise under differing conditions of carbohydrate supplementation.

Adult↗

PubMed2006

NCAA rule change improves weight loss among national championship wrestlers.

PURPOSE: The present investigation was initiated to examine the weight management practices among wrestlers participating in the NCAA Division I, II, and III wrestling tournaments. Part 1 examined the efficacy of body composition assessment between preseason (PRE) and postseason (POST). Part 2 examined rapid weight loss (RWL) during the 20 h preceding the weigh-in and the rapid weight gained (RWG) during the first day's competition. METHODS: Subjects include 811 competitors from Divisions I, II, and III participating in the NCAA national championship tournaments between 1999 and 2004. Measurements included relative body fatness (% BF) and weight (WT) on the day preceding the tournament and the evening of the first day. Minimal weight (MW) was computed with 5% BF. Retrospectively, MW, % BF, and WT from the previous fall were obtained for comparisons from NCAA records. RESULTS: Part 1: WT and % BF decreased significantly PRE (WT 74.0 +/- 11.1 kg; % BF 12.3 +/- 3.4%) to POST (WT 71.5 +/- 10.4 kg; % BF 9.5 +/- 1.8%), but MW (PRE MW 68.0 +/- 9.2 kg, POST MW 67.9 +/- 9.1 kg) remained unchanged. Heavier wrestlers and Division I and II wrestlers showed the greatest changes in WT and % BF. Part 2: RWL averaged (+/- SD) 1.2 +/- 0.9 kg and relative to weight 1.7 +/- 1.2%. Division I and lighter wrestlers showed the greatest change. RWG averaged 0.9 +/- 0.8 kg, or 1.3 +/- 1.2%. RWG was greater among lighter and Division I and II wrestlers. CONCLUSIONS: Minimal weight estimates PRE appear valid compared with POST. RWL and RWG are reduced significantly over previous investigations with only mat-side weigh-ins. The NCAA weight management program appears effective in reducing unhealthy weight cutting behaviors and promoting competitive equity. Efforts to institute similar programs among younger wrestlers seem warranted.

Body Composition↗

PubMed2005

Effect of resistance exercise and carbohydrate ingestion on oxidative stress.

Some research studies have produced data indicating that resistance exercise induces oxidative stress, despite minimal increases in VO(2). These studies have primarily relied on oxidative stress markers with low sensitivity and debatable reliability. However, F(2)-isoprostanes as measured by gas chromatography mass spectrometry are considered to be a reliable and precise indicator of oxidative stress. Carbohydrate ingestion during exercise is associated with reduced levels of stress hormones, which may influence oxidative stress and plasma antioxidant potential. Therefore, the purpose of this study was to investigate the influence of carbohydrate ingestion during resistance training on F(2)-isoprostanes and plasma antioxidant potential. Thirty strength-trained subjects were randomized to carbohydrate (CHO) or placebo (PLA) groups that lifted weights for 2 h. Subjects received 10 ml kg(- 1) h(- 1) CHO (6%) or PLA beverages during the exercise. Blood and vastus lateralis muscle biopsy samples were collected before and after exercise and analyzed for cortisol as a marker of general stress, F(2)-isoprostanes as a measure of oxidative stress, and ferric reducing ability of plasma (FRAP) as a measure of antioxidant potential, and for muscle glycogen, respectively. Decreases in muscle glycogen content did not differ between CHO and PLA. Cortisol and FRAP increased significantly in CHO and PLA (P = 0.008 and 0.044, respectively), but the pattern of change was not different between groups. F(2)-isoprostanes were unaffected by exercise. These results indicate that exhaustive resistance exercise and carbohydrate ingestion have no effect on oxidative stress or plasma antioxidant potential in trained subjects.

Adult↗

PubMed2005

Evaluation of leg-to-leg BIA in assessing body composition of high-school wrestlers.

PURPOSE: To evaluate the accuracy of leg-to-leg bioelectrical impedance analysis (BIA) in assessing fat-free mass (FFM) using the TBF-300WA in comparison with hydrostatic weighing (HW) and skinfolds (SK) in high-school (HS) wrestlers in a hydrated state. METHODS: Body composition was determined by BIA, HW, and three-site SK in 129 HS wrestlers (mean +/- SD, age: 15.5 +/- 1.3, height 1.70 +/- 0.08 m, body mass 65.6 +/- 13.1 kg). For all methods, body density (Db) was converted to percent body fat (%BF) using the Brozek equation. Hydration state was quantified by evaluating urine specific gravity. RESULTS: There were no significant differences for estimated FFM between BIA (56.9 +/- 8.4 kg) and HW (56.2 +/- 9.9 kg) or between SK (56.1 +/- 8.9 kg) and HW. The standard errors of estimate for FFM with HW as the reference method were 3.64 kg for BIA and 1.97 kg for SK. Significant correlations were found for FFM between HW and BIA (r = 0.93, P < 0.001), and between HW and SK (r = 0.98, P < 0.001). The FFM difference between BIA and HW was significantly correlated with the FFM average of the two methods (r = -0.39, P < 0.001). The FFM difference between SK and HW was also significantly correlated with the FFM average (r = -0.44, P < 0.001). CONCLUSIONS: This study demonstrates that SK should be considered as the preferred field method of estimating the FFM of HS wrestlers because of its greater individual precision than the leg-to-leg BIA method. Although the BIA is an attractive assessment tool and easy to use, it should be recommended as an alternative to the SK method only when trained skinfold technicians are not available.

Adolescent↗

PubMed2005

Muscle cytokine mRNA changes after 2.5 h of cycling: influence of carbohydrate.

PURPOSE: To study the effect of carbohydrate compared to placebo ingestion on plasma cytokines and muscle cytokine mRNA following 2.5 h of intensive cycling in 15 trained cyclists. METHODS: Fifteen trained cyclists cycled for 2.5 h at 60% Wmax on two occasions while receiving 4 mL.kg.15 min carbohydrate (6%) (CHO) or placebo (PLA) beverages in a randomized, counterbalanced design. Blood and vastus lateralis muscle biopsy samples were collected before and after exercise and 12 h postexercise and compared to samples taken from five cyclists who rested in the lab during the exercise sessions. Blood cell counts were determined, and plasma was analyzed for interleukin (IL)-6, IL-10, IL-1 receptor antagonist (ra), IL-8, cortisol, epinephrine, glucose, and insulin. Muscle was analyzed for glycogen content and relative gene expression of four cytokines, IL-6, IL-8, tumor necrosis factor (TNF) alpha, and IL-1beta, using real-time quantitative reverse transcriptase polymerase chain reaction. RESULTS: Plasma glucose and insulin were higher, and epinephrine, cortisol, IL-6, IL-10, and IL-1ra, but not IL-8, were significantly lower postexercise in CHO versus PLA. Muscle glycogen content decreased 68% immediately postexercise and the pattern of change did not differ between CHO and PLA. Muscle IL-6, IL-8, TNF-alpha, but not IL-1beta mRNA increased immediately postexercise compared to controls, with no differences between CHO and PLA. CONCLUSION: CHO compared to PLA beverage ingestion attenuated the increase in plasma cortisol, epinephrine, IL-6, IL-10, and IL-1ra, but not muscle IL-6, IL-8, and TNF-alpha mRNA in athletes cycling 2.5 h at 60% Wmax.

Bicycling↗

PubMed2005

Carbohydrate supplementation and perceived exertion during resistance exercise.

The purpose of the present study was to investigate the relationship between carbohydrate energy substrate and the perception of exertion during resistance exercise. Thirty strength-trained subjects were randomized to a carbohydrate group (C) or a placebo group (P), and lifted weights for 2 hours (4 sets; 10 repetitions maximum; 10 exercises; 2-3-minute rest intervals). Subjects ingested 10 ml.kg(-1).h(-1) of 6% carbohydrate or placebo beverages during the resistance-training bout. The 15-category Borg Perceived Exertion Scale was used to assess overall body (RPE-O) and active muscle (RPE-AM) perceived exertion after completion of the last repetition in each set for each exercise. No significant differences were found between the C and P groups for either RPE-O or RPE-AM, with the exception of RPE-O for the upright row and back squat (p < 0.05). Carbohydrate supplementation exerted no attenuating effect on ratings of perceived exertion (RPE) during resistance training.

Adult↗

PubMed2004

Carbohydrate supplementation and perceived exertion during prolonged running.

PURPOSE: The purpose of this study was to investigate the relationship between carbohydrate energy substrate and hormonal regulation on the perception of exertion during prolonged running. METHODS: Sixteen experienced marathoners ran on treadmills for 3 h at approximately 70% VO2max on two occasions while receiving 1 L x h carbohydrate (C) or placebo (P) beverages. Blood and vastus lateralis muscle biopsy samples were collected before and after exercise. RESULTS: The pattern of change in ratings of perceived exertion (RPE) over time was significantly different between C and P ingestion (P < 0.01) with attenuated RPE responses found in the latter part of the 3 h run. The pattern of change in the respiratory exchange ratio and carbohydrate oxidation rates were significantly greater (P < 0.01) in the C than P condition. Change in muscle glycogen content did not differ between C and P (P = 0.246). C relative to P ingestion was associated with higher plasma levels of glucose, insulin, and lactate and lower levels plasma cortisol. CONCLUSIONS: These data indicate that a lower RPE was associated with a higher carbohydrate oxidation, plasma glucose, and insulin levels, and lower plasma cortisol during prolonged running after C supplementation as compared with P feeding despite no differences in muscle glycogen content. These findings support a physiological link between RPE and carbohydrate substrate availability as well as selected hormonal regulation during prolonged running.

Adult↗

PubMed2004

Validation of the Adult OMNI Scale of perceived exertion for walking/running exercise.

PURPOSE: Concurrent and construct validity of the OMNI-Walk/Run Scale of Perceived Exertion was examined using young adult women and men (18-36 yr). METHODS: Concurrent validity was established by correlating OMNI-Walk/Run Scale ratings of perceived exertion (RPE-OMNI) with oxygen uptake (VO2), relative maximal oxygen uptake (%VO2(max)), ventilation (VE), respiratory rate (RR), respiratory exchange ratio (RER), and heart rate (HR) to a graded exercise test on a treadmill. Construct validity was established by correlating RPE-OMNI with RPE from the Borg (6-20) Scale (RPE-BORG). Measurements were made every min throughout the test. RESULTS: The range of exercise responses across the incremental walking/running test for the female and male groups were: VO2 = 0.99-3.9 L x min(-1), HR = 98-190 beats x min(-1) and RPE-OMNI = 1.3-9.4. Correlation/regression analyses indicated that RPE-OMNI distributed as a positive linear function for all criterion measures; r = 0.67 to 0.88 (P < 0.05). RPE-OMNI was positively and linearly related to the RPE-BORG; r = 0.96 (P < 0.01) for both the female and male groups. CONCLUSIONS: Concurrent and construct evidence supports use of the OMNI-Walk/Run Scale by adult women and men to estimate RPE during graded exercise test on a treadmill.

Adolescent↗

PubMed2004

Comparison of measured and predicted residual lung volume in determining body composition of collegiate wrestlers.

This investigation compared percent fat obtained via underwater weighing using measured and predicted residual lung volume (RLV) in euhydrated and hypohydrated collegiate wrestlers (N = 67). RLV was measured using O(2) rebreathing or O(2) dilution and predicted using 3 equations-Equation 1: (0.019 x height [cm]) + (0.0115 x age [years]) - 2.24; Equation 2: (0.017 x age [years]) + (0.06858 x height [in.]) - 3.477; and Equation 3: (0.0275 age [years]) + (0.0189 height [cm]) - 2.6139. Percent fat determined using RLV Equation 2 did not differ from the value obtained using measured RLV in the euhydrated (10.9 +/- 5.1 vs. 11.5 +/- 5.6% fat) or hypohydrated (10.8 +/- 5.1 vs. 12.3 +/- 5.6% fat) trials. All other percent fat values differed (p < 0.05) from the value obtained using measured RLV in euhydrated subjects. The use of RLV Equation 2 may be a practical alternative to measured RLV in determining percent fat in euhydrated and hypohydrated collegiate wrestlers.

Adipose Tissue↗

PubMed2003

Regulating intensity using perceived exertion during extended exercise periods.

The present study was undertaken to examine the validity of using the OMNI scale of perceived exertion to regulate intensity during extended exercise periods. Forty-eight subjects (24 male, 24 female) were recruited and each subject completed a maximal graded exercise test (GXT) and two 20-min submaximal exercises. During the GXT, ratings of perceived exertion (RPE) as well as oxygen uptake (VO(2)) and heart rate (HR) equivalent to 50 and 70% of maximum VO(2) (VO(2max)) were estimated. During each submaximal exercise, subjects were instructed to produce and maintain a workload equivalent to the RPE estimated at 50 or 70% VO(2max), and VO(2) and HR were measured every 5 min throughout the exercise. Of the 48 subjects, 12 (6 male and 6 female) performed both the estimation and production trials on a treadmill (TM/TM), 12 (6 male and 6 female) performed both the estimation and production trials on a cycle ergometer (C/C), 12 (6 male and 6 female) performed the estimation trial on a treadmill and the production trial on a cycle ergometer (TM/C), and 12 (6 male and 6 female) performed the estimation trial on a cycle ergometer and the production trial on a treadmill (C/TM). No differences in VO(2) between the estimation and any 5 min of the production trial were observed at either intensity in TM/TM and C/C. No differences in HR between the estimation and any 5 min of the production trial were also observed at 50% VO(2max) in TM/TM and at both 50 and 70% VO(2max) in C/C. However, HR was higher at 20th min of the production trial at 70% VO(2max) in TM/TM. Both the VO(2) and HR were generally lower in TM/C and higher in C/TM. However, these differences diminished when values were normalized using VO(2max) of the same mode that other groups had attained. These data suggest that under both intra- and intermodal conditions, using the OMNI perceived exertion scale is effective not only in establishing the target intensity at the onset of exercise, but also in maintaining the intensity throughout a 20-min exercise session.

Adaptation, Physiological↗

PubMed2003

Influence of vitamin C supplementation on oxidative and salivary IgA changes following an ultramarathon.

This randomized study measured the influence of vitamin C ( N=15) compared to placebo ( N=13) supplementation on oxidative and salivary immunoglobulin A (sIgA) changes in runners competing in an ultramarathon race. Seven days prior to the race, subjects ingested in randomized, double-blind fashion three 500-mg tablets of vitamin C or placebo each day. On race day, blood and saliva samples were collected 1 h pre-race, after 32 km of running, and then again immediately post-race. During the race, runners received 1 l/h carbohydrate beverages (60 g/l) with vitamin C (150 mg/l) or without in a double-blinded fashion. The runners also ingested two to three carbohydrate gel packs per hour (25 g each). Subjects in both groups ran a mean of 69 km (range 48-80 km) in 9.8 h (range 5-12 h) and maintained an intensity of approximately 75% maximal heart rate (HR(max)) throughout the ultramarathon race. Plasma ascorbic acid was higher in the vitamin C compared to placebo group pre-race, and increased significantly in the vitamin C group during the race [post-race, 3.21 (0.29) and 1.28 (0.12) microg/100 microl, respectively, P<0.001]. No significant group or interaction effects were measured for lipid hydroperoxide and F(2)-isoprostane, but both oxidative measures rose significantly during the ultramarathon race. Saliva volume, sIgA concentration, sIgA secretion and sIgA:saliva protein ratio all decreased significantly (P<0.001) during the race, but the pattern of change in all saliva measures did not differ significantly between groups. No significant correlations were found between post-race plasma vitamin C, oxidative, and saliva measures, except for a positive correlation between post-race serum cortisol and serum vitamin C (r=0.50, P=0.006). These data indicate that vitamin C supplementation in carbohydrate-fed runners does not serve as a countermeasure to oxidative and sIgA changes during or following a competitive ultramarathon race.

Administration, Oral↗

PubMed2003

Influence of carbohydrate ingestion on oxidative stress and plasma antioxidant potential following a 3 h run.

Concentrations of reactive oxygen species (ROS) increase during exercise secondary to increased oxygen uptake, xanthine oxidase activity, and immune system activation. Carbohydrate compared to placebo beverage ingestion is associated with an attenuated cortisol and catecholamine response. Catecholamines can undergo autooxidation to form ROS. We hypothesized that during intense exercise, ingestion of carbohydrate compared to placebo would diminish oxidative stress. Sixteen experienced marathoners ran on treadmills for 3 h at approximately 70% VO2(max) on two occasions while receiving carbohydrate or placebo beverages (11/h, double-blinded) in a randomized, counterbalanced order. Blood samples were collected before and immediately after exercise, snap frozen in liquid nitrogen, and stored at -80 degrees C until analysis. Plasma samples were analyzed for F2-isoprostanes (FIP) and lipid hydroperoxides (ROOH) as measures for lipid peroxidation, ferric reducing ability of plasma (FRAP) as a measure of plasma antioxidant potential and for cortisol. The pattern of change in cortisol was significantly different between carbohydrate and placebo conditions (P = 0.024), with post-exercise levels higher in the placebo condition. Under both carbohydrate and placebo conditions, significant increases in FIP, ROOH, and FRAP were measured, but the pattern of increase was not different (FIP, interaction effect, P = 0.472; ROOH, P = 0.572; FRAP, P = 0.668). Despite an attenuation in the cortisol response, carbohydrate compared to placebo ingestion does not counter the increase in oxidative stress or modulate plasma antioxidant potential in athletes running 3 h at 70% VO2(max).

Adult↗

PubMed2003

Evaluation of air displacement for assessing body composition of collegiate wrestlers.

PURPOSE: To evaluate the accuracy of air displacement plethysmography (ADP) by using the BOD POD in comparison with hydrostatic weighing (HW) in a collegiate wrestling population in hydrated and acutely dehydrated states. METHODS: Body composition was determined by ADP, HW, and three-site skinfolds (SK) in 66 NCAA Division I collegiate wrestlers before and after acute dehydration (2.6% reduction in body mass). For all methods, body density (D(b)) was converted to percent body fat (%BF) by using the Brozek equation for Euro-Americans and the Schutte equation for African-Americans. RESULTS: There were no significant differences between ADP and HW for D(b), %BF, and fat-free mass (FFM) in either the hydrated or dehydrated states. The standard errors of the estimate for %BF estimated from ADP with HW as the reference method were 2.12% (hydrated) and 2.16% (dehydrated); prediction errors were 2.35% (hydrated) and 2.49% (dehydrated). Bland-Altman plots of D(b) and %BF showed no systematic bias, and 64 out 66 subjects fell within the 95% limits of agreement (mean difference +/- 2 SD) for both variables. For SK, %BF was significantly higher than HW in both the hydrated and dehydrated state. All methods (ADP, HW, and SK) showed a significant decrease in FFM from the hydrated to the dehydrated state. CONCLUSIONS: This study demonstrates that the BOD POD air displacement method provides similar estimates of D (b), %BF, and FFM when compared with HW in a heterogeneous collegiate wrestling population during hydrated and acutely dehydrated states. Pretest guidelines to ensure normal hydration status before body composition assessment using any method must be followed to minimize measurement error in %BF.

Adipose Tissue↗

PubMed2003

Ratings of perceived exertion throughout an ultramarathon during carbohydrate ingestion.

Ratings of perceived exertion (RPE) and their relation to selected physiological mediators during endurance exercise have been limited to laboratory settings. The present study characterized the pattern of change in perceptual responses and examined the relation between RPE and selected physiological variables during a long competitive sporting event, i.e., an ultramarathon race (68 km). A single-group design was employed in which all of the 28 subjects provided their perceptual ratings 11.9 +/- 0.2) and heart rate (HR) (138 +/- 3) periodically (every 5 km) throughout the ultramarathon, and selected physiological responses were measured before, once during (32 km), and immediately after the race. Runners drank approximately 1,000 ml of carbohydrate beverage each hour (60 gm carbohydrate hr.(-1)) and ate 2 or 3 carbohydrate gel packs per hour (25 gm each(-1)). RPE increased significantly throughout the course of the ultramarathon. No significant correlations were found between RPE and HR at any time throughout the ultramarathon. RPE averaged 10.4 +/- 0.4 at the beginning of the race (6.4 km) and 15.4 +/- 0.4 at the conclusion of the race. Subjects maintained 76.9 +/- 1.1% of maximal heart rate; however, there was a tendency for heart rate to drop significantly after 32 km. Significant time main effects were found for serum glucose, insulin, and cortisol throughout the race. However, no significant correlations were found between RPE and any of these physiological mediators. These data indicate that during an ultramarathon race there is a progressive increase in RPE without an accompanying increase in HR or decrease in blood glucose. Therefore, during competitive self-paced exercise the perceptual responses may be mediated through other neurological and physiological mechanisms.

Adult↗

PubMed2002

Reducing diet and/or exercise training decreases the lipid and lipoprotein risk factors of moderately obese women.

OBJECTIVE: This study was designed to measure the influence of diet, exercise or both on serum lipids and lipoproteins in obese women. METHODS: Obese subjects were randomly divided into one of four groups: diet alone (1,200-1,300 kcal/day, NCEP, Step I), exercise alone (five 45 minute sessions per week at 78.4+/-0.5% maximum heart rate), exercise and diet, and controls. Maximal aerobic power, body composition, diet, serum lipids and lipoproteins were measured in all subjects at baseline and after a 12-week intervention period. Subjects included 91 moderately obese (45.6+/-1.1 y, body mass index 33.1+/-0.6 kg/m2) and 30 nonobese (43.2+/-2.3 y, body mass index 21.4+/-0.34 kg/m2) women who were recruited from the surrounding community. Independent t tests were used to compare obese and nonobese subjects at baseline. The 12-week intervention data from the obese groups were analyzed using a 4 x 2 repeated measures ANOVA design. RESULTS: Cross-sectional comparisons at baseline showed obese subjects had significantly higher total cholesterol, triacylglycerol. total cholesterol/HDL-C and LDL-C values and lower HDL-C values. Prospective results showed that subjects in diet and exercise and diet lost 7.8+/-0.7 and 8.1+/-0.6 kg body mass, with no significant change for exercise relative to control. Serum cholesterol and triacylglycerol improved in both diet and in exercise and diet after 12 weeks of intervention, and was most strongly related to weight loss. CONCLUSION: Weight loss is the most effective means of reducing lipid and lipoprotein risk factors in obese women.

Adult↗

PubMed2002

Physical activity among ethnically diverse college students.

The authors compared physical activity patterns among 874 Asian, 332 African, 1,101 White, and 529 Hispanic American college students aged 18 to 25 years. According to self-report responses, 46.7% of the sample did not engage in vigorous physical activity and 16.7% were physically inactive. Among women, ethnic-specific rates of physical inactivity were Asian, 28.1%; African, 23.5%; White, 17.4%; and Hispanic, 20.3%. For men, rates of inactivity were Asian 11.7%; African, 7.7%; White, 12.0%; and Hispanic, 13.8. Weight-training activity, youthful physical activity, and TV viewing accounted for a significant portion of the variance in physical activity levels (13.1% for women and 14.8% for men). The results of this study support the need for physical activity interventions for college students, particularly minorities.

Adolescent↗