Biomedical subjects

Conrad P Earnest

Publications and source records attributed to Conrad P Earnest.

At least 19 recordsLinked to original sources

PubMed2006

Does creatine supplementation improve functional capacity in elderly women?

The purpose of this study was to determine the effects of short-term (7 days) oral creatine supplementation (0.3 g.kg(-1)) in elderly women during exercise tests that reflect functional capacity during daily living tasks. We assessed several indices of endurance capacity (1-mile walk test, gross mechanical efficiency, ventilatory threshold, and peak oxygen intake determined during cycle-ergometry) and lower-extremity functional performance (time to complete sit-stand test). Subjects were assigned to a creatine (n = 10; age 67 +/- 6 years) or placebo (n = 6; age 68 +/- 4 years) group. We found a significant improvement only after creatine loading in the sit-stand test (placebo: 9.7 +/- 0.9 seconds for pretest and 9.3 +/- 0.7 seconds for posttest, p > 0.05; creatine: 10.0 +/- 0.7 seconds for pretest and 8.8 +/- 1.1 seconds for posttest). Significance was recorded at p < 0.05 for the interaction effect (group [creatine, placebo] x time [pretest, posttest]). In elderly women, short-term oral creatine supplementation does not improve endurance capacity but increases the ability to perform lower-body functional living tasks involving rapid movements.

Activities of Daily Living↗

PubMed2006

Is cardiorespiratory fitness related to quality of life in survivors of breast cancer?

The purpose of this study was to investigate whether indices of cardiorespiratory fitness are related to quality of life (QOL) in women survivors of breast cancer. Using the European Organization for Research and Treatment of Cancer QLQ-30 questionnaire, we assessed the QOL of 16 participants (age, 50 +/- 9 years; body mass, 66.6 +/- 9.6 kg). All participants performed incremental cycle ergometer exercise to determine several indices of cardiorespiratory fitness (e.g., peak oxygen uptake [.V(O2)peak, in L.min(-1), ml.kg(-1).min(-1)]), peak power output (PPO, in W), PPO/ body mass (W.kg(-1), peak heart rate (HRpeak, b.min(-1), peak ventilation (VEpeak), and .V(O2) and heart rate (HR) at the ventilatory (VT) and respiratory compensation (RCT) thresholds. Relationships between QOL and variables were assessed using Spearman rank-difference correlation tests. A significant inverse relationship (p < 0.05) was found for QOL scores and values for age (years) and body mass (kg) ( = -0.53), %HRpeak@VT ( = -0.59) and %VEpeak@VT ( = -0.61). A significant positive relationship (p < 0.05) was found for QOL and PPO/body mass ( = 0.59) and HRpeak ( = 0.78), .V(O2)@RCT (ml.kg(-1.min(-1) ( = 0.51), power output (PO, expressed as either W or W.kg(-1) at RCT, and HR at RCT ( = 0.54). No other significant relationship was found between QOL and variables obtained from the tests. In conclusion, these findings highlight possible relationships between cardiorespiratory fitness and well-being in survivors of breast cancer. From a practical point of view, our data emphasize the need for this population to engage in programmed cardiorespiratory exercise training, mainly designed to improve VT and RCT. The improvement of both submaximal indices can have a beneficial effect on QOL.

Age Factors↗

PubMed2006

The effects of protein and amino acid supplementation on performance and training adaptations during ten weeks of resistance training.

The purpose of this study was to examine the effects of whey protein supplementation on body composition, muscular strength, muscular endurance, and anaerobic capacity during 10 weeks of resistance training. Thirty-six resistance-trained males (31.0 +/- 8.0 years, 179.1 +/- 8.0 cm, 84.0 +/- 12.9 kg, 17.8 +/- 6.6%) followed a 4 days-per-week split body part resistance training program for 10 weeks. Three groups of supplements were randomly assigned, prior to the beginning of the exercise program, in a double-blind manner to all subjects: 48 g per day (g.d(-1)) carbohydrate placebo (P), 40 g.d(-1) of whey protein + 8 g.d(-1) of casein (WC), or 40 g.d(-1) of whey protein + 3 g.d(-1) branched-chain amino acids + 5 g.d(-1) L-glutamine (WBG). At 0, 5, and 10 weeks, subjects were tested for fasting blood samples, body mass, body composition using dual-energy x-ray absorptiometry (DEXA), 1 repetition maximum (1RM) bench and leg press, 80% 1RM maximal repetitions to fatigue for bench press and leg press, and 30-second Wingate anaerobic capacity tests. No changes (p > 0.05) were noted in all groups for energy intake, training volume, blood parameters, and anaerobic capacity. WC experienced the greatest increases in DEXA lean mass (P = 0.0 +/- 0.9; WC = 1.9 +/- 0.6; WBG = -0.1 +/- 0.3 kg, p < 0.05) and DEXA fat-free mass (P = 0.1 +/- 1.0; WC = 1.8 +/- 0.6; WBG = -0.1 +/- 0.2 kg, p < 0.05). Significant increases in 1RM bench press and leg press were observed in all groups after 10 weeks. In this study, the combination of whey and casein protein promoted the greatest increases in fat-free mass after 10 weeks of heavy resistance training. Athletes, coaches, and nutritionists can use these findings to increase fat-free mass and to improve body composition during resistance training.

Absorptiometry, Photon↗

PubMed2005

PPARGC1A genotype (Gly482Ser) predicts exceptional endurance capacity in European men.

Animal and human data indicate a role for the peroxisome proliferator-activated receptor-gamma coactivator 1alpha (PPARGC1A) gene product in the development of maximal oxygen uptake (V(O2 max)), a determinant of endurance capacity, diabetes, and early death. We tested the hypothesis that the frequency of the minor Ser482 allele at the PPARGC1A locus is lower in World-class Spanish male endurance athletes (cases) [n = 104; mean (SD) age: 26.8 (3.8) yr] than in unfit United Kingdom (UK) Caucasian male controls [n = 100; mean (SD) age: 49.3 (8.1) yr]. In cases and controls, the Gly482Ser genotype met Hardy-Weinberg expectations (P > 0.05 in both groups tested separately). Cases had significantly higher V(O2 max) [73.4 (5.7) vs. 29.4 ml x kg(-1) x min(-1) (3.8); P < 0.0001] and were leaner [body mass index: 20.6 (1.5) vs. 27.6 kg/m2 (3.9); P < 0.0001] than controls. In unadjusted chi2 analyses, the frequency of the minor Ser482 allele was significantly lower in cases than in controls (29.1 vs. 40.0%; P = 0.01). To assess the possibility that genetic stratification could confound these observations, we also compared Gly482Ser genotype frequencies in Spanish (n = 164) and UK Caucasian men (n = 381) who were unselected for their level of fitness. In these analyses, Ser482 allele frequencies were very similar (36.9% in Spanish vs. 37.5% in UK Caucasians, P = 0.83), suggesting that confounding by genetic stratification is unlikely to explain the association between Gly482Ser genotype and endurance capacity. In summary, our data indicate a role for the Gly482Ser genotype in determining aerobic fitness. This finding has relevance from the perspective of physical performance, but it may also be informative for the targeted prevention of diseases associated with low fitness such as Type 2 diabetes.

Adult↗

PubMed2005

Cholesterol-lowering effects of bovine serum immunoglobulin in participants with mild hypercholesterolemia.

BACKGROUND: The consumption of milk products has been shown to lower cholesterol. The mechanism of action surrounding this observation has been attributed to the protein fraction of milk and serum. OBJECTIVE: We examined the effect of an oral serum bovine immunoglobulin protein fraction (bIg) derived from US Department of Agriculture-approved beef (aged <30 mo) on lipid indexes in humans. DESIGN: Participants included men and women (aged 25-70 y) with hypercholesterolemia (5.44-6.99 mmol/L) who were not receiving cholesterol-lowering medication. Treatment consisted of the randomized, double-blind, parallel-group, placebo-controlled administration of 5 g bIg for 6 wk in 52 participants (n = 26 each in treatment and control groups). RESULTS: Mean (+/-SD) total cholesterol (TC) at baseline was 6.33 +/- 0.1 mmol/L for bIg and 6.16 +/- 0.1 mmol/L for placebo. A repeated-measures multivariate analysis of covariance covaried for change in total energy and alcohol intake and Tukey's post hoc examination of our data showed that the bIg-treated group had a significant reduction in TC at 3 wk (5.98 +/- 0.5 mmol/L; P < 0.05) and 6 wk (5.97 +/- 0.7 mmol/L; P < 0.05). The concentration at 6 wk was significantly different from that in the placebo group (P < 0.05). This reduction was largely due to a decrease in LDL cholesterol in the bIg-treated group from baseline (4.12 +/- 0.6 mmol/L) at 3 wk (3.92 +/- 0.7 mmol/L, P < 0.05) and at 6 wk (3.84 +/- 0.6 mmol/L, P < 0.05); the 6-wk concentration differed significantly between the treatment and placebo groups (P < 0.05). We observed no significant changes in the placebo group or in any other lipid indexes or markers associated with hepatorenal or cardiovascular function. CONCLUSION: Consumption of bIg appears to positively modulate the primary lipid indexes associated with cardiovascular disease.

Adult↗

PubMed2005

Does intermittent hypoxia increase erythropoiesis in professional cyclists during a 3-week race?

In this study we examined the effects of intermittent hypoxia exposure (IHE) in a group of professional cyclists (n = 6; age 26 +/- 1 yr) competing in the 2001 Vuelta a España. After each daily stage, treated subjects received four 5-min bouts of normobaric IHE (mean O2 concentration of 12.6%, simulating a mean altitude of 4,000 m) interspersed with 5-min bouts of breathing hotel room air (normoxia) until completing a total IHE of 20-min duration. The primary outcome, compared to a control group of similar characteristics not receiving IHE (n = 5; age 25 +/- 1 yr), was the % increase in erythropoietin (Epo) from the beginning to the end of the Vuelta. Statistical analysis showed that Epo increase tended to be higher (p = 0.052) in the IHE group than in controls (37.4 +/- 5.8% vs. -4.4 +/- 19.5%, respectively). However IHE had no effect on reticulocytes or erythrocyte count (p > 0.05).

Adult↗

PubMed2005

How do endurance runners actually train? Relationship with competition performance.

PURPOSE: To quantify the relationship between total training load and running performance during the most important competitions of the season (national cross-country championships, 4.175- and 10.130-km races). METHODS: Eight well-trained, subelite endurance runners (age (mean+/-SD): 23+/-2 yr; VO2max: 70.0+/-7.3 mL.kg.min) performed a maximal cardiorespiratory exercise test before the training period to determine ventilatory threshold (VT) and respiratory compensation threshold (RCT). Heart rate was continuously recorded using telemetry during each training session over a 6-month macrocycle, designed to achieve peak performance during the aforementioned cross-country races, lasting from late August to the time that these races were held, that is, mid-February. This allowed us to quantify the total cumulative time spent in three intensity zones calculated as zone 1 (low intensity, lower than the VT); zone 2 (moderate intensity, between VT and RCT); and zone 3 (high intensity, above the RCT). RESULTS: Total training time in zone 1 (4581+/-979 min) was significantly higher (P<0.001) than that accumulated in zones 2 (1354+/-583 min) and 3 (487+/-154 min). Total time in zone 2 was significantly higher than time in zone 3 (P<0.05). A correlation coefficient of r=-0.79 (P=0.06) and r=-0.97 (P=0.008) was found between the total training time spent in zone 1 and performance time during the short and long cross-country races, respectively. CONCLUSIONS: Our findings suggest that total training time spent at low intensities might be associated with improved performance during highly intense endurance events, especially if the event duration is approximately 35 min. Interventional studies (i.e., improving or reducing training time in zone 1) are needed to corroborate our findings and to elucidate the physiological mechanisms behind them.

Adaptation, Physiological↗

PubMed2005

Reliability of the Lode Excalibur Sport Ergometer and applicability to Computrainer electromagnetically braked cycling training device.

New technology allows cyclists to train via power output (PO) in addition to heart rate (HR). For those athletes undertaking seasonal laboratory testing (e.g., Vo(2), lactate threshold), it is imperative that athletes be able to directly apply this information to their training device. We examined the reliability of a standardized laboratory ergometer (Lode Excalibur Sport) and its applicability to an electromagnetically braked ergometer (Computrainer) in 2 phases. Phase I (n = 12) examined the reliability of the Lode. Phase II (n = 14) compared the Lode to the Computrainer using a randomized, counterbalance assignment. Following warm-up, each trial started at 100 W, progressing 50 W every 3 minutes to exhaustion. Outcomes were time-to-exhaustion (TTE), peak PO (W) (PO(peak)), peak HR (HR(peak)), and ventilatory (VT) and respiratory compensation (RCP) thresholds. We used a repeated measures analysis of variance (ANOVA), Tukey post hoc analysis, regression analysis, Bland-Altman plots, and coefficient of variation (CV) analysis for each variable. During phase I, we found no significant difference for any variable, minimal dispersion of Vo(2) during Bland-Altman analysis, and a low CV at each test stage (</= 5%). During phase II, significant differences and higher CV for most parameters (all data; p < 0.001) were observed for Lode versus Computrainer: TTE (21 minutes, 12 seconds +/- 3 minutes, 12 seconds vs. 19 minutes, 9 seconds +/- 2 minutes, 36 seconds; CV = 16%), PO(peak) (335 +/- 57.8 W vs. 295 +/- 47.1 W, CV = 17%), as well as PO at VT (CV = 51%) and RCP (CV = 24%; p < 0.01). We conclude that coaches and cyclists may need to use some caution when directly transferring results obtained from laboratory testing to the Computrainer training device.

Bicycling↗

PubMed2005

Cordyceps sinensis- and Rhodiola rosea-based supplementation in male cyclists and its effect on muscle tissue oxygen saturation.

Cordyceps sinensis (Cs) and Rhodiola rosea (Rr) are herbs used in traditional Chinese medicine to treat a multitude of ailments as well as to enhance performance. The purpose of this research was to examine the effects of a formula containing Cs and Rr (Cs-Rr) on circulatory dynamics, specifically muscle tissue oxygen saturation (Sto(2)), in male subjects during maximal exercise. This study followed a double blind, randomized, placebo-treatment, pre-post test design. Capsules were administered to 8 subjects who were randomly assigned to 1 of 2 groups. The treatment group received Cs-Rr, and the control group received a placebo. All subjects performed 2 exercise stress tests to volitional fatigue on a cycle load ergometer. There were no significant (p </= 0.05) differences in Sto(2) slope, Sto(2) threshold (Sto(2T)), Vo(2)max, ventilatory threshold (V(T)), or time to exhaustion (T(E)) between or within the treatment or control group. In conclusion, Cs-Rr did not significantly enhance Sto(2).

Adolescent↗

PubMed2004

Eight weeks of moderate-intensity exercise training increases heart rate variability in sedentary postmenopausal women.

BACKGROUND: Regular exercise is associated with increased heart rate variability (HRV). However, results from studies examining the effect of exercise training on HRV in postmenopausal women are inconclusive. In addition, the effect of hormone replacement therapy (HRT) on HRV remains a subject of speculation. METHODS: We examined 88 sedentary postmenopausal women in a randomized controlled trial who were assigned to exercise (n = 49) or control (n = 39) groups. The exercising women performed 8 weeks of aerobic exercise training at a heart rate equivalent to 50% of VO2max, consisting on average of 44 minutes per session, 3 to 4 times per week. Resting HRV was measured in each participant at baseline and after 8 weeks of intervention. Ten minutes of resting R-R intervals were analyzed by time (standard deviation of mean R-R intervals, root of mean square successive differences) and frequency domain methods: low-frequency (LF) was defined as 0.04 to 0.15 Hz, high-frequency (HF) as 0.15 to 0.40 Hz, and total spectral power as 0.00 to 0.40 Hz. The LF and HF components in normalized units were also calculated. RESULTS: At baseline, there were no significant differences in HRV between control and exercise groups. Additionally, there were no differences in any HRV variables when women were grouped by HRT use (no HRT, estrogen-only HRT, and progestin-containing HRT). After 8 weeks, women randomly assigned to the exercise group increased all absolute time and frequency domain indexes (all P <.001) and reduced resting heart rate (P =.002) compared with women in the control group. The LF and HF components expressed as normalized units remained unchanged after exercise intervention. Additionally, HRT use did not modify the exercise-induced changes in HRV. CONCLUSIONS: We conclude that moderate aerobic exercise increases HRV in sedentary postmenopausal women. This benefit is not influenced by the use of HRT.

Analysis of Variance↗

PubMed2004

Dose Response to Exercise in Women aged 45-75 yr (DREW): design and rationale.

INTRODUCTION AND PURPOSE: Physical inactivity in postmenopausal women contributes to a rise in atherogenic risk factors associated with the metabolic syndrome. Although regular physical activity positively contributes to health, inactivity progressively increases with age. The Dose Response to Exercise in Women aged 45-75 yr (DREW) study is designed to investigate the effect of different amounts of exercise training on cardiorespiratory fitness and risk factors for cardiovascular disease (CVD) in postmenopausal women at moderately increased risk of CVD. METHODS: DREW will recruit 450 sedentary, healthy, postmenopausal women with a body mass index of 25-40 kg.m-2, resting systolic blood pressure (BP) of 120-159 mm Hg, and a resting diastolic BP of < or = 99 mm Hg. Laboratory and self-report measures completed at baseline and 6 months include maximal oxygen consumption (.VO2max), resting BP, anthropometry, dietary habits, physical activity history, medication use, menstrual history, personal and family medical history, and fasting HDL cholesterol, LDL cholesterol, triglycerides, and glucose. Eligible participants are randomly assigned to a nonexercise group or one of three exercise groups. Participants exercise 3 to 4x wk-1 at a heart rate equivalent to 50% of .VO2max expending 4, 8, or 12 kcal.kg-1.wk-1, depending on group assignment. This study will allow quantification of possible dose-response relations (50%, 100%, and 150% of the consensus physical activity recommendation) between exercise training and study outcomes. CONCLUSION: DREW can make important contributions to our understanding of the effects of physical activity in postmenopausal women and help refine public health and clinical recommendations for this group.

Adaptation, Physiological↗

PubMed2004

Effects of a commercial herbal-based formula on exercise performance in cyclists.

INTRODUCTION/PURPOSE: We examined the effects of a commercially marketed herbal-based formula purported to increase endurance on oxygen consumption (VO2) in 17 competitive category III/IV amateur cyclists [mean (SEM) age: 31.1 (1.8) yr; height: 178.5 (1.8) cm; weight: 77.1 (1.6) kg]. METHODS: Each cyclist participated in two (pre/post) cycling tests progressing 25 W.4 min(-1) starting at 100 W administered in a randomized, placebo-controlled, double-blind fashion. The second trial was performed 14 d after the ingestion of a manufacturer recommended loading phase (4 d x 6 caps.d(-1)) and a maintenance phase (11 d x 3 caps.d(-1)). Three treatment capsules contained 1000 mg of Cordyceps sinensis (CS-4) and 300 mg Rhodiola rosea root extract as the primary ingredients; 800 mg of other ingredients included calcium pyruvate, sodium phosphate, potassium phosphate, ribose, and adenosine and 200 mcg of chromium. RESULTS: Using a 2 x 2 ANOVA, we observed no significant treatment effect for any between or within group variables including peak VO2 [treatment 4.14 (0.2) L.min(-1); placebo 4.10 (0.2) L.min(-1)], time to exhaustion [treatment 38.47 (1.7) min; placebo 36.95 (1.8) min], peak power output (PO) [treatment 300.00 (12.1) W; placebo 290.63 (12.9) W], or peak heart rate. We also observed no differences for any subpeak exercise variable including the PO eliciting 2 mmol.L(-1) blood lactate (BLa) [treatment 201.00 (18.1) W; placebo 167.50 (19.2) W] and 4 mmol.L(-1) BLa [treatment 235.88 (15.8) W; placebo 244.78 (14.9) W], ventilatory threshold, respiratory compensation point, or Vo2 L.min(-1) gross efficiency at each stage. CONCLUSION: A 2-wk ingestion schema of a commercial herbal-based formula is insufficient to elicit positive changes in cycling performance.

Adult↗

PubMed2004

Effects of oral ATP supplementation on anaerobic power and muscular strength.

PURPOSE: We examined 14 d of oral adenosine 5'-triphosphate (ATP) supplementation on indices of anaerobic capacity and muscular strength. METHODS: Twenty-seven healthy males successfully completed the trial, after randomly receiving in a double-blind manner an oral dose of low dose (150 mg) or high dose (225 mg) ATP, or matched placebo. To improve absorption characteristics, the ATP was enterically coated. Total blood ATP (whole blood and plasma ATP) concentrations, two Wingate anaerobic power tests (30 s), and muscular strength (1RM and three sets of repetitions to fatigue at 70% of 1RM) were measured under three conditions: (i) baseline; (ii) acutely (7d later, no prior supplementation and 75 min after ATP ingestion); and (iii) after 14 d of daily ingestion (post). RESULTS: Statistical analyses showed no significant between or within group treatment effects for whole blood ATP or plasma ATP concentrations for any treatment condition. We also did not observe any treatment effects for any Wingate testing parameter including peak PO, total work, average PO for 30 s, or post-Wingate lactate accumulation. Overall, we observed no significant between group treatment effects for any muscular strength parameter. We did observe several within group differences for the group ingesting the high ATP dosage including 1RM (6.6%; P < 0.04) and repetitions to fatigue during set 1 of posttesting (18.5%; P < 0.007) and total lifting volume at post (22%; P < 0.003). CONCLUSIONS: We conclude that enterically coated oral ATP supplementation may provide small ergogenic effects on muscular strength under some treatment conditions.

Adenosine Triphosphate↗

PubMed2004

Associations of muscle strength and fitness with metabolic syndrome in men.

PURPOSE: To examine the associations for muscular strength and cardiorespiratory fitness with the prevalence of metabolic syndrome among men. METHODS: Participants were 8570 men (20-75 yr) for whom an age-specific muscular strength score was computed by combining the body weight adjusted one-repetition maximum measures for the leg press and the bench press. Cardiorespiratory fitness was quantified by age-specific maximal treadmill exercise test time. RESULTS: Separate age and smoking adjusted logistic regression models revealed a graded inverse association for metabolic syndrome prevalence with muscular strength (beta = -0.37, P < 0.0001) and cardiorespiratory fitness (beta = -1.2, P < 0.0001). The association between strength and metabolic syndrome was attenuated (beta = -0.08, P < 0.01) when further adjusted for cardiorespiratory fitness. The association between cardiorespiratory fitness and metabolic syndrome was unchanged (beta = -1.2, P < 0.0001) after adjusting for strength. Muscular strength added to the protective effect of fitness among men with low (P trend = 0.0002) and moderate (P trend < 0.0001) fitness levels. Among normal weight (BMI < 25), overweight (BMI 25-30), and obese (BMI >or= 30) men, respectively, being strong and fit was associated with lower odds (73%, 69%, and 62% respectively, P < 0.0001) of having prevalent metabolic syndrome. CONCLUSIONS: Muscular strength and cardiorespiratory fitness have independent and joint inverse associations with metabolic syndrome prevalence.

Adult↗

PubMed2004

Effects of cardiorespiratory fitness on healthcare utilization.

BACKGROUND: Prospective study examining the relationship between cardiorespiratory fitness level and incidence of medical treatments during a 1-yr period before each of two examinations. A subset was also evaluated to assess whether improvement in fitness affected incidence of treatments. METHODS AND RESULTS: Part I: Six thousand six hundred seventy-nine healthy male subjects underwent medical examinations on two occasions, including a maximal exercise test. Division of subjects by fitness into quartiles (Q1 = low fitness through Q4 = high fitness) revealed an inverse relationship between fitness and outcome measures. Men in the low-fitness group had more office visits and overnight hospital stays than men in the high-fitness group (3.5% (Q1) vs 1.6% (Q4) men had 10+ office visits, and 10% (Q1) vs 5.0% (Q4) men had overnight hospital stays, P < 0.0001). These differences held after adjustment for potential confounding variables (age, follow-up yr, blood pressure, cholesterol, and smoking). Part II: Subjects in this subset (N = 2974) were evaluated to compare overnight hospital stays between low-fit men who remained low fit at the second examination, and low-fit men who became fit by the second examination. This cohort was divided into fitness tertiles (T1 = low fitness through T3 = high fitness). Those who improved their fitness by the time of the second examination had a decreased number of overnight hospital stays, compared with those who remained unfit at the time of the second examination (10.2% (T1 at second visit) vs 5.9% (T3 at second visit) had overnight hospital stays, P < 0.03). CONCLUSIONS: Men who maintain or become fit are less likely to have physician visits or overnight hospital stays, compared with men who are unfit.

Adult↗

PubMed2004

Low vs. high glycemic index carbohydrate gel ingestion during simulated 64-km cycling time trial performance.

We examined the effect of low and high glycemic index (GI) carbohydrate (CHO) feedings during a simulated 64-km cycling time trial (TT) in nine subjects ([mean +/- SEM], age = 30 +/- 1 years; weight = 77.0 +/- 2.6 kg). Each rider completed three randomized, double blind, counter-balanced, crossover rides, where riders ingested 15 g of low GI (honey; GI = 35) and high GI (dextrose; GI = 100) CHO every 16 km. Our results showed no differences between groups for the time to complete the entire TT (honey = 128 minutes, 42 seconds +/- 3.6 minutes; dextrose = 128 minutes, 18 seconds +/- 3.8 minutes; placebo = 131 minutes, 18 seconds +/- 3.9 minutes). However, an analysis of total time alone may not portray an accurate picture of TT performance under CHO-supplemented conditions. For example, when the CHO data were collapsed, the CHO condition (128 minutes, 30 seconds) proved faster than placebo condition (131 minutes, 18 seconds; p < 0.02). Furthermore, examining the percent differences and 95% confidence intervals (CI) shows the two CHO conditions to be generally faster, as the majority of the CI lies in the positive range: placebo vs. dextrose (2.36% [95% CI; -0.69, 4.64]) and honey (1.98% [95% CI; -0.30, 5.02]). Dextrose vs. honey was 0.39% (95% CI; -3.39, 4.15). Within treatment analysis also showed that subjects generated more watts (W) over the last 16 km vs. preceding segments for dextrose (p < 0.002) and honey (p < 0.0004) treatments. When the final 16-km W was expressed as a percentage of pretest maximal W, the dextrose treatment was greater than placebo (p < 0.05). A strong trend was noted for the honey condition (p < 0.06), despite no differences in heart rate (HR) or rate of perceived exertion (RPE). Our results show a trend for improvement in time and wattage over the last 16 km of a 64-km simulated TT regardless of glycemic index.

Adult↗

PubMed2004

Exercise capacity and body composition as predictors of mortality among men with diabetes.

OBJECTIVE: To quantify the relation of fitness to mortality among men with diabetes, adjusted for BMI and within levels of BMI. RESEARCH DESIGN AND METHODS: In this observational cohort study, we calculated all-cause death rates in men with diabetes across quartiles of fitness and BMI categories. Study participants were 2,196 men with diabetes (average age 49.3 years, SD 9.5) who underwent a medical examination, including a maximal exercise test, during 1970 to 1995, with mortality follow-up to 31 December 1996. RESULTS: We identified 275 deaths during 32,161 person-years of observation. Risk of all-cause mortality was inversely related to fitness. For example, in the fully adjusted model, the risk of mortality was 4.5 (2.6-7.6), 2.8 (1.6-4.7), and 1.6 (0.93-2.76) for the first, second, and third fitness quartiles, respectively, with the fourth quartile (highest fitness level) as the referent (P for trend <0.0001). There was no significant trend across BMI categories for mortality after adjustment for fitness. Similar results were found when the fitness-mortality relation was examined within levels of body composition. In normal-weight men with diabetes, the relative risks of mortality were 6.6 (2.8-15.0), 3.2 (1.4-7.0), and 2.2 (1.1-4.6) for the first, second, and third quartiles of fitness, respectively, as compared with the fourth quartile (P for trend <0.0001). We found similar results in the overweight and obese weight categories. CONCLUSIONS: There was a steep inverse gradient between fitness and mortality in this cohort of men with documented diabetes, and this association was independent of BMI.

Blood Pressure↗

PubMed2003

Reduction of C-reactive protein levels through use of a multivitamin.

PURPOSE: Elevated C-reactive protein levels are associated with the risk of cardiovascular disease and diabetes. We examined whether multivitamins reduce C-reactive protein levels. METHODS: We performed a post hoc subgroup analysis of a 6-month, randomized, double-blind, placebo-controlled trial. Patients (n = 87; mean age, 53 years) for whom frozen plasma samples were available; who did not have an inflammatory condition at baseline; and who were not hospitalized, taking antibiotics, smoking, or starting statin therapy during the study were included. C-reactive protein and plasma vitamin levels were measured at baseline and 6 months. RESULTS: At 6 months, C-reactive protein levels were significantly lower in the multivitamin group than in the placebo group (between-group difference = -0.91 mg/L; 95% confidence interval: -1.52 to -0.30; P= 0.005). The reduction in C-reactive protein levels was most evident in patients who had elevated levels (> or =1.0 mg/L) at baseline. Of the six vitamins measured (C, E, B(6), B(12), folate, and beta carotene), only vitamin B(6) (baseline: r = -0.31, P= 0.003; 6 months: r = -0.29, P= 0.006) and vitamin C (baseline: r = -0.25, P= 0.02) were inversely associated with C-reactive protein level. CONCLUSION: In a post hoc analysis of a randomized, double-blind, placebo-controlled study, multivitamin use was associated with lower C-reactive protein levels. Other similarly formulated multivitamins may yield comparable results.

Adult↗