Metabolic Syndrome and Related Disorders, Jan 1, 2005
... ERIC C. WESTMAN, MDMHS,1 WILLIAM S. YANCY, Jr., MDMHS,1 MARK D. HAUB, Ph.D.,2 and JEFF S. VOL... more ... ERIC C. WESTMAN, MDMHS,1 WILLIAM S. YANCY, Jr., MDMHS,1 MARK D. HAUB, Ph.D.,2 and JEFF S. VOLEK, Ph.DRD3 ... 4. Hamilton J, Cummings E, Zdravkovic V, Finegood D, Daneman D. Metformin as an adjunct therapy in adolescents with type 1 diabetes and insulin ...
Athletes are continually searching for means to optimize their performance. Within the past 20 ye... more Athletes are continually searching for means to optimize their performance. Within the past 20 years, athletes and scientists have reported or observed that consuming a carbohydrate-restricted diet may improve performance. The original theories explaining the purported benefits centered on the fact that fat oxidation increases, thereby “sparing” muscle glycogen. More recent concepts that explain the plausibility of the ergogenicity of low-carbohydrate, or high-fat, diets on exercise performance pertain to an effect similar to altitude training. We and others have observed that although fat oxidation may be increased, the ability to maintain high-intensity exercise (above the lactate threshold) seems to be compromised or at least indifferent when compared with consumption of more carbohydrate. That said, clinical studies clearly demonstrate that ad libitum low-carbohydrate diets elicit greater decreases in body weight and fat than energy-equivalent low-fat diets, especially over a short duration. Thus, although low-carbohydrate and high-fat diets appear detrimental or indifferent relative to performance, they may be a faster means to achieve a more competitive body composition.
ABSTRACT
Objectives: To explore the relationship between adult attention deficit hyperactivity d... more ABSTRACT
Objectives: To explore the relationship between adult attention deficit hyperactivity disorder (ADHD) subtypes and neuropsychological functioning among U.S. soldiers. Methods: Deploying soldiers (N = 260) completed the World Health Organization Adult ADHD Self-Report Scale (ASRS) Screener. Cognitive tests, a deployment health-history questionnaire, and the post-traumatic stress disorder (PTSD) Checklist-Military Version were completed by subsamples of available participants. Results: The prevalence of positive ASRS screens was 10.4%. ASRS scores were correlated with PTSD avoidance (N = 63, ρ = 0.37, p = 0.003), hyperarousal (N = 63, ρ = 0.25, p = 0.047), and total PTSD scores (N = 62, ρ = 0.33, p = 0.009); and all six moods (e.g., anger, anxiety) scale scores (N = 110; ρ = −0.37 to 0.43). ASRS was also correlated with scores on the match-to-sample (N = 110, ρ = −0.23, p = 0.014) and emotional Stroop (N = 108, ρ = −0.23, p = 0.016) tasks. In addition, a differential pattern between subtypes of ADHD was noted with regard to cognitive functioning, mood, and combat stress symptomatology. Conclusions: Although the results are preliminary given the sample size, the prevalence and comorbidities of ADHD appear to be similar among military and nonmilitary populations.
Age-related increases in oxidative stress contribute to impaired skeletal muscle vascular control... more Age-related increases in oxidative stress contribute to impaired skeletal muscle vascular control. However, recent evidence indicates that antioxidant treatment with tempol (4-hydroxy-2,2,6,6-tetramethylpiperidine-1-oxyl) attenuates flow-mediated vasodilation in isolated arterioles from the highly oxidative soleus muscle of aged rats. Whether antioxidant treatment with tempol evokes similar responses in vivo at rest and during exercise in senescent individuals and whether this effect varies based on muscle fiber type composition are unknown. We tested the hypothesis that redox modulation via acute systemic tempol administration decreases vascular conductance (VC) primarily in oxidative hindlimb locomotor muscles at rest and during submaximal whole body exercise (treadmill running at 20 m/min, 5% grade) in aged rats. Eighteen old (25-26 mo) male Fischer 344 x Brown Norway rats were assigned to either rest (n = 8) or exercise (n = 10) groups. Regional VC was determined via radiolabeled microspheres before and after intra-arterial administration of tempol (302 μmol/kg). Tempol decreased mean arterial pressure significantly by 9% at rest and 16% during exercise. At rest, similar VC in 26 out of 28 individual hindlimb muscles or muscle parts following tempol administration compared with control resulted in unchanged total hindlimb muscle VC (control: 0.18 ± 0.02; tempol: 0.17 ± 0.05 ml·min(-1)·100 g(-1)·mmHg(-1); P > 0.05). During exercise, all individual hindlimb muscles or muscle parts irrespective of fiber type composition exhibited either an increase or no change in VC with tempol (i.e., ↑11 and ↔17 muscles or muscle parts), such that total hindlimb VC increased by 25% (control: 0.93 ± 0.04; tempol: 1.15 ± 0.09 ml·min(-1)·100 g(-1)·mmHg(-1); P ≤ 0.05). These results demonstrate that acute systemic administration of the antioxidant tempol significantly impacts the control of regional vascular tone in vivo presumably via redox modulation and improves skeletal muscle vasodilation independently of fiber type composition during submaximal whole body exercise in aged rats.
BackgroundFor elderly women, insufficient data exist to assess the accuracy of the assumed mean p... more BackgroundFor elderly women, insufficient data exist to assess the accuracy of the assumed mean protein requirement of 0.6 g of protein · kg−1 · day−1, and the adequacy of the current Recommended Dietary Allowance (RDA) of 0.8 g of protein · kg−1 · day−1. The aims of this study were to assess the mean protein requirement and suggested safe and adequate protein intake (protein allowance) of elderly women using a shorter-term nitrogen balance protocol.MethodsDuring three separate 18-day trials, 11 elderly women (age range, 70–81 years) were randomly fed eucaloric diets designed to provide either 0.50, 0.75, or 1.00 g of protein · kg−1 · day−1. Nitrogen balance was determined at Weeks 2 and 3 (Days 7–10 and 14–17, respectively) of each trial using data from total nitrogen analyses of duplicate food composites, 24-hour urine collections, and stool collections. The mean protein requirement was calculated using linear regression of individual women's data from all three trials and inverse prediction.ResultsAt protein intakes of 0.53 ± 0.02, 0.76 ± 0.02, or 1.06 ± 0.05 g of protein · kg−1 · day−1, net nitrogen balances during Week 2 were −14.5 ± 3.1, 3.8 ± 2.5 and 23.4 ± 3.3 mg of nitrogen · kg−1 · day−1, respectively, for these body weight– and body composition–stable women. At Week 3, the net nitrogen balances were −0.1 ± 2.7, 8.5 ± 3.6 and 42.0 ± 3.0 mg of nitrogen · kg−1 · day−1. From Week 2 to Week 3, shifts to more positive nitrogen balances occurred due to decreases in urinary nitrogen excretion. The mean protein requirement at Week 2 was calculated to be 0.70 ± 0.09 g of protein · kg−1 · day−1 (coefficient of variation [CV] = 13%) and at Week 3 was calculated to be 0.56 ± 0.09 g of protein · kg−1 · day−1 (CV = 17%). From these data, an adequate protein allowance was estimated to be greater than the RDA at Week 2 (0.90 g of protein · kg−1 · day [d]−1), and not different than the RDA at Week 3 (0.76 g of protein · kg−1 · d−1).ConclusionsThe decrease over time in urinary nitrogen excretion from Week 2 to Week 3 suggests that these elderly women did not achieve a metabolic steady state during this shorter-term nitrogen balance study. Collectively, these data suggest that the total protein needs of elderly women are at or above the current RDA for protein. However, the results of this study indicate that shorter-term nitrogen balance protocols are insufficient to firmly establish the RDA for protein of elderly women, and further research is required using alternative criteria measures.
Abstract It is obvious that buffers elicit a physiological response by increasing the buffering c... more Abstract It is obvious that buffers elicit a physiological response by increasing the buffering capacity of blood and muscle. Also, there is convincing data that these compounds can enhance performance. 51 However, an athlete's decision to use these compounds should ...
Metabolic Syndrome and Related Disorders, Jan 1, 2005
... ERIC C. WESTMAN, MDMHS,1 WILLIAM S. YANCY, Jr., MDMHS,1 MARK D. HAUB, Ph.D.,2 and JEFF S. VOL... more ... ERIC C. WESTMAN, MDMHS,1 WILLIAM S. YANCY, Jr., MDMHS,1 MARK D. HAUB, Ph.D.,2 and JEFF S. VOLEK, Ph.DRD3 ... 4. Hamilton J, Cummings E, Zdravkovic V, Finegood D, Daneman D. Metformin as an adjunct therapy in adolescents with type 1 diabetes and insulin ...
Athletes are continually searching for means to optimize their performance. Within the past 20 ye... more Athletes are continually searching for means to optimize their performance. Within the past 20 years, athletes and scientists have reported or observed that consuming a carbohydrate-restricted diet may improve performance. The original theories explaining the purported benefits centered on the fact that fat oxidation increases, thereby “sparing” muscle glycogen. More recent concepts that explain the plausibility of the ergogenicity of low-carbohydrate, or high-fat, diets on exercise performance pertain to an effect similar to altitude training. We and others have observed that although fat oxidation may be increased, the ability to maintain high-intensity exercise (above the lactate threshold) seems to be compromised or at least indifferent when compared with consumption of more carbohydrate. That said, clinical studies clearly demonstrate that ad libitum low-carbohydrate diets elicit greater decreases in body weight and fat than energy-equivalent low-fat diets, especially over a short duration. Thus, although low-carbohydrate and high-fat diets appear detrimental or indifferent relative to performance, they may be a faster means to achieve a more competitive body composition.
ABSTRACT
Objectives: To explore the relationship between adult attention deficit hyperactivity d... more ABSTRACT
Objectives: To explore the relationship between adult attention deficit hyperactivity disorder (ADHD) subtypes and neuropsychological functioning among U.S. soldiers. Methods: Deploying soldiers (N = 260) completed the World Health Organization Adult ADHD Self-Report Scale (ASRS) Screener. Cognitive tests, a deployment health-history questionnaire, and the post-traumatic stress disorder (PTSD) Checklist-Military Version were completed by subsamples of available participants. Results: The prevalence of positive ASRS screens was 10.4%. ASRS scores were correlated with PTSD avoidance (N = 63, ρ = 0.37, p = 0.003), hyperarousal (N = 63, ρ = 0.25, p = 0.047), and total PTSD scores (N = 62, ρ = 0.33, p = 0.009); and all six moods (e.g., anger, anxiety) scale scores (N = 110; ρ = −0.37 to 0.43). ASRS was also correlated with scores on the match-to-sample (N = 110, ρ = −0.23, p = 0.014) and emotional Stroop (N = 108, ρ = −0.23, p = 0.016) tasks. In addition, a differential pattern between subtypes of ADHD was noted with regard to cognitive functioning, mood, and combat stress symptomatology. Conclusions: Although the results are preliminary given the sample size, the prevalence and comorbidities of ADHD appear to be similar among military and nonmilitary populations.
Age-related increases in oxidative stress contribute to impaired skeletal muscle vascular control... more Age-related increases in oxidative stress contribute to impaired skeletal muscle vascular control. However, recent evidence indicates that antioxidant treatment with tempol (4-hydroxy-2,2,6,6-tetramethylpiperidine-1-oxyl) attenuates flow-mediated vasodilation in isolated arterioles from the highly oxidative soleus muscle of aged rats. Whether antioxidant treatment with tempol evokes similar responses in vivo at rest and during exercise in senescent individuals and whether this effect varies based on muscle fiber type composition are unknown. We tested the hypothesis that redox modulation via acute systemic tempol administration decreases vascular conductance (VC) primarily in oxidative hindlimb locomotor muscles at rest and during submaximal whole body exercise (treadmill running at 20 m/min, 5% grade) in aged rats. Eighteen old (25-26 mo) male Fischer 344 x Brown Norway rats were assigned to either rest (n = 8) or exercise (n = 10) groups. Regional VC was determined via radiolabeled microspheres before and after intra-arterial administration of tempol (302 μmol/kg). Tempol decreased mean arterial pressure significantly by 9% at rest and 16% during exercise. At rest, similar VC in 26 out of 28 individual hindlimb muscles or muscle parts following tempol administration compared with control resulted in unchanged total hindlimb muscle VC (control: 0.18 ± 0.02; tempol: 0.17 ± 0.05 ml·min(-1)·100 g(-1)·mmHg(-1); P > 0.05). During exercise, all individual hindlimb muscles or muscle parts irrespective of fiber type composition exhibited either an increase or no change in VC with tempol (i.e., ↑11 and ↔17 muscles or muscle parts), such that total hindlimb VC increased by 25% (control: 0.93 ± 0.04; tempol: 1.15 ± 0.09 ml·min(-1)·100 g(-1)·mmHg(-1); P ≤ 0.05). These results demonstrate that acute systemic administration of the antioxidant tempol significantly impacts the control of regional vascular tone in vivo presumably via redox modulation and improves skeletal muscle vasodilation independently of fiber type composition during submaximal whole body exercise in aged rats.
BackgroundFor elderly women, insufficient data exist to assess the accuracy of the assumed mean p... more BackgroundFor elderly women, insufficient data exist to assess the accuracy of the assumed mean protein requirement of 0.6 g of protein · kg−1 · day−1, and the adequacy of the current Recommended Dietary Allowance (RDA) of 0.8 g of protein · kg−1 · day−1. The aims of this study were to assess the mean protein requirement and suggested safe and adequate protein intake (protein allowance) of elderly women using a shorter-term nitrogen balance protocol.MethodsDuring three separate 18-day trials, 11 elderly women (age range, 70–81 years) were randomly fed eucaloric diets designed to provide either 0.50, 0.75, or 1.00 g of protein · kg−1 · day−1. Nitrogen balance was determined at Weeks 2 and 3 (Days 7–10 and 14–17, respectively) of each trial using data from total nitrogen analyses of duplicate food composites, 24-hour urine collections, and stool collections. The mean protein requirement was calculated using linear regression of individual women's data from all three trials and inverse prediction.ResultsAt protein intakes of 0.53 ± 0.02, 0.76 ± 0.02, or 1.06 ± 0.05 g of protein · kg−1 · day−1, net nitrogen balances during Week 2 were −14.5 ± 3.1, 3.8 ± 2.5 and 23.4 ± 3.3 mg of nitrogen · kg−1 · day−1, respectively, for these body weight– and body composition–stable women. At Week 3, the net nitrogen balances were −0.1 ± 2.7, 8.5 ± 3.6 and 42.0 ± 3.0 mg of nitrogen · kg−1 · day−1. From Week 2 to Week 3, shifts to more positive nitrogen balances occurred due to decreases in urinary nitrogen excretion. The mean protein requirement at Week 2 was calculated to be 0.70 ± 0.09 g of protein · kg−1 · day−1 (coefficient of variation [CV] = 13%) and at Week 3 was calculated to be 0.56 ± 0.09 g of protein · kg−1 · day−1 (CV = 17%). From these data, an adequate protein allowance was estimated to be greater than the RDA at Week 2 (0.90 g of protein · kg−1 · day [d]−1), and not different than the RDA at Week 3 (0.76 g of protein · kg−1 · d−1).ConclusionsThe decrease over time in urinary nitrogen excretion from Week 2 to Week 3 suggests that these elderly women did not achieve a metabolic steady state during this shorter-term nitrogen balance study. Collectively, these data suggest that the total protein needs of elderly women are at or above the current RDA for protein. However, the results of this study indicate that shorter-term nitrogen balance protocols are insufficient to firmly establish the RDA for protein of elderly women, and further research is required using alternative criteria measures.
Abstract It is obvious that buffers elicit a physiological response by increasing the buffering c... more Abstract It is obvious that buffers elicit a physiological response by increasing the buffering capacity of blood and muscle. Also, there is convincing data that these compounds can enhance performance. 51 However, an athlete's decision to use these compounds should ...
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Papers by Mark Haub
Objectives: To explore the relationship between adult attention deficit hyperactivity disorder (ADHD) subtypes and neuropsychological functioning among U.S. soldiers. Methods: Deploying soldiers (N = 260) completed the World Health Organization Adult ADHD Self-Report Scale (ASRS) Screener. Cognitive tests, a deployment health-history questionnaire, and the post-traumatic stress disorder (PTSD) Checklist-Military Version were completed by subsamples of available participants. Results: The prevalence of positive ASRS screens was 10.4%. ASRS scores were correlated with PTSD avoidance (N = 63, ρ = 0.37, p = 0.003), hyperarousal (N = 63, ρ = 0.25, p = 0.047), and total PTSD scores (N = 62, ρ = 0.33, p = 0.009); and all six moods (e.g., anger, anxiety) scale scores (N = 110; ρ = −0.37 to 0.43). ASRS was also correlated with scores on the match-to-sample (N = 110, ρ = −0.23, p = 0.014) and emotional Stroop (N = 108, ρ = −0.23, p = 0.016) tasks. In addition, a differential pattern between subtypes of ADHD was noted with regard to cognitive functioning, mood, and combat stress symptomatology. Conclusions: Although the results are preliminary given the sample size, the prevalence and comorbidities of ADHD appear to be similar among military and nonmilitary populations.
Objectives: To explore the relationship between adult attention deficit hyperactivity disorder (ADHD) subtypes and neuropsychological functioning among U.S. soldiers. Methods: Deploying soldiers (N = 260) completed the World Health Organization Adult ADHD Self-Report Scale (ASRS) Screener. Cognitive tests, a deployment health-history questionnaire, and the post-traumatic stress disorder (PTSD) Checklist-Military Version were completed by subsamples of available participants. Results: The prevalence of positive ASRS screens was 10.4%. ASRS scores were correlated with PTSD avoidance (N = 63, ρ = 0.37, p = 0.003), hyperarousal (N = 63, ρ = 0.25, p = 0.047), and total PTSD scores (N = 62, ρ = 0.33, p = 0.009); and all six moods (e.g., anger, anxiety) scale scores (N = 110; ρ = −0.37 to 0.43). ASRS was also correlated with scores on the match-to-sample (N = 110, ρ = −0.23, p = 0.014) and emotional Stroop (N = 108, ρ = −0.23, p = 0.016) tasks. In addition, a differential pattern between subtypes of ADHD was noted with regard to cognitive functioning, mood, and combat stress symptomatology. Conclusions: Although the results are preliminary given the sample size, the prevalence and comorbidities of ADHD appear to be similar among military and nonmilitary populations.