Choline plays a central role in many physiological pathways, including neurotransmitter synthesis (acetylcholine), cell-membrane signaling (phospholipids), lipid transport (lipoproteins), and methyl-group metabolism (homocysteine reduction). Endurance exercise might stress several of these pathways, increasing the demand for choline as a metabolic substrate. This review examines the current literature linking endurance exercise and choline demand in the human body. Also reviewed are the mechanisms by which exercise might affect blood choline levels, and the links between methyl metabolism and the availability of free choline are highlighted. Finally, the ability of oral choline supplements to augment endurance performance is assessed. Most individuals consume adequate amounts of choline, although there is evidence that current recommendations might be insufficient for some adult men. Only strenuous and prolonged physical activity appears sufficient to significantly decrease circulating choline stores. Moreover, oral choline supplementation might only increase endurance performance in activities that reduce circulating choline levels below normal.
Jason T. Penry and Melinda M. Manore
Lindsey E. Miller, Graham R. McGinnis, Brian Kliszczewicz, Dustin Slivka, Walter Hailes, John Cuddy, Charles Dumke, Brent Ruby and John C. Quindry
Oxidative stress occurs as a result of altitude-induced hypobaric hypoxia and physical exercise. The effect of exercise on oxidative stress under hypobaric hypoxia is not well understood.
To determine the effect of high-altitude exercise on blood oxidative stress. Nine male participants completed a 2-d trek up and down Mt Rainer, in North America, at a peak altitude of 4,393 m. Day 1 consisted of steady-pace climbing for 6.25 hr to a final elevation of 3,000 m. The 4,393-m summit was reached on Day 2 in approximately 5 hr. Climb–rest intervals varied but were consistent between participants, with approximately 14 hr of total time including rest periods. Blood samples were assayed for biomarkers of oxidative stress and antioxidant potential at the following time points: Pre (before the trek), 3Kup (at ascent to 3,000 m), 3Kdown (at 3,000 m on the descent), and Post (posttrek at base elevation). Blood serum variables included ferric-reducing antioxidant potential (FRAP), Trolox equivalent antioxidant capacity (TEAC), protein carbonyls (PC), and lipid hydroperoxides. Serum FRAP was elevated at 3Kup and 3Kdown compared with Pre and Post values (p = .004, 8% and 11% increase from Pre). Serum TEAC values were increased at 3Kdown and Post (p = .032, 10% and 18% increase from Pre). Serum PC were elevated at 3Kup and 3Kdown time points (p = .034, 194% and 138% increase from Pre), while lipid hydroperoxides were elevated Post only (p = .004, 257% increase from Pre).
Findings indicate that high-altitude trekking is associated with increased blood oxidative stress.
Jingmei Dong, Peijie Chen, Qing Liu, Ru Wang, Weihua Xiao and Yajun Zhang
To examine the excessive reactive oxygen species (ROS) mediated by nicotinamide adenine dinucleotide phosphate (NADPH) oxidase and the combined effect of glutamine supplementation and diphenyleneiodonium (DPI) on the function of neutrophils induced by overtraining.
Fifty male Wistar rats were randomly divided into 5 groups: control group (C), overtraining group (E), DPI-administration group (D), glutamine-supplementation group (G), and combined DPI and glutamine group (DG). Blood was sampled from the orbital vein after rats were trained on treadmill for 11 wk. Cytokine and lipid peroxidation in blood plasma were measured by enzyme-linked immunosorbent assay. The colocalization between gp91phox and p47phox of the NADPH oxidase was detected using immunocytochemistry and confocal microscopy. The activity of NADPH oxidase was assessed by chemiluminescence. Neutrophils’ respiratory burst and phagocytosis function were measured by flow cytometry.
NADPH oxidase was activated by overtraining. Cytokine and lipid peroxidation in blood plasma and the activity of NADPH oxidase were markedly increased in Group E compared with Group C. Neutrophil function was lower in Group E than Group C. Both lower neutrophils function and higher ROS production were reversed in Group DG. The glutamine and DPI interference alone in Group D and Group G was less effective than DPI and glutamine combined in group DG.
Activation of NADPH oxidase is responsible for the production of superoxide anions, which leads to excessive ROS and is related to the decrease in neutrophil function induced by overtraining. The combined DPI administration and glutamine supplementation reversed the decreased neutrophil function after overtraining.
Edith Filaire, Alain Massart, Hugues Portier, Matthieu Rouveix, Fatima Rosado, Anne S. Bage, Mylène Gobert and Denys Durand
The aim of this investigation was to assess the effects of 6 wk of eicosapentanoic acid (EPA) and docosahexanoic acid (DHA) supplementation on resting and exercise-induced lipid peroxidation and antioxidant status in judoists. Subjects were randomly assigned to receive a placebo or a capsule of polyunsaturated fatty acids (PUFAs; 600 mg EPA and 400 mg DHA). Blood samples were collected in preexercise and postexercise conditions (judo-training session), both before and after the supplementation period. The following parameters were analyzed: α-tocopherol, retinol, lag phase, maximum rate of oxidation (Rmax) during the propagating chain reaction, maximum amount of conjugated dienes (CDmax) accumulated after the propagation phase, nitric oxide (NO) and malondyaldehide (MDA) concentrations, salivary glutathione peroxidase activity, and the lipid profile. Dietary data were collected using a 7-day dietary record. A significant interaction effect between supplementation and time (p < .01) on triglycerides was noted, with values significantly lower in the n-3 long-chain-PUFA (LCPUFA) group after supplementation than in the placebo group. Significant interaction effects between supplementation and time on resting MDA concentrations and Rmax were found (p = .03 and p = .04, respectively), with elevated values in the n-3 LCPUFA group after supplementation and no change in the placebo group’s levels. The authors observed a significantly greater NO and oxidative-stress increase with exercise (MDA, Rmax, CDmax, and NO) in the n-3 LCPUFA group than with placebo. No main or interaction effects were found for retinol and α-tocopherol. These results indicate that supplementation with n-3 LCPUFAs significantly increased oxidative stress at rest and after a judo-training session.
Arlette C. Perry, Linda S. Crane, Brooks Applegate, Sylvia Marquez-Sterling, Joseph F. Signorile and Paul C. Miller
The present study showed that amenorrheic athletes (AAs) scored higher on the Eating Attitudes Test (EAT) (p < .05) than eumenorrheic athletes (EAs), indicating more aberrant eating patterns in the first group. Scores on the EAT were inversely correlated with fat intake (p < .05), simple carbohydrate intake (p < .01), and percentage saturation of iron (p < .05) and were positively correlated with total iron binding capacity (p < .01) for the total sample. Physiological assessment of athletes revealed that there were no significant differences between groups in serum lipoproteins, with both EAs and AAs having serum lipid profiles indicative of low cardiovascular risk. Furthermore, low-density lipoprotein cholesterol was the only lipoprotein significantly and positively correlated with serum estradiol levels for the entire sample (p = .01). The present study was in agreement with previous work showing that scores on the EAT represent a primary difference between EAs and AAs; the present study was somewhat different than previous work in that serum lipoproteins were not significantly related to menstrual status.
James H. Rimmer, David Braddock and Glenn Fujiura
A body mass index (BMI) greater than 27 has been cited as a risk factor for heart disease and diabetes mellitus resulting from excess weight. The purpose of this study was to determine the association between BMI (>27) and two other obesity indices–height-weight and percent body fat–as well as to investigate the relationship between BMI and three blood lipid parameters–total cholesterol, low-density lipoprotein cholesterol (LDL-C), and high-density lipoprotein cholesterol (HDL-C) in 329 adults with mental retardation (MR). Males were significantly taller and heavier than females, but females had a significantly higher BMI. Kendall’s Tau-C revealed a significant association between BMI and each of the following: height-weight, percent body fat, LDL-C, and HDL-C. However, there were a significant number of false negatives and false positives on each of the criteria. The congruence between at-risk BMI and two other obesity parameters (height-weight and percent body fat) in a population of adults with MR is not strong. Professionals should employ the BMI along with skinfold measures to assess a person’s at-risk status for excess weight.
Yandiswa Y. Yako, Mogamat S. Hassan, Rajiv T. Erasmus, Lize van der Merwe, Susan Janse van Rensburg and Tandi Edith Matsha
There is evidence demonstrating that the contribution of sedentary behavior and effect of physical activity on metabolic phenotypes is mediated by polymorphisms in genes.
The type and frequency of physical activity was assessed by means of structured questionnaires in 1555 South African school learners. Anthropometric measurements, blood pressure, fasting blood glucose and lipids were measured using standard procedures. The effect of different types and frequency of physical activity on obesity-related traits was assessed in relation to MC3R T6K and V81I genotypes in 430 of the learners.
Levels of total cholesterol were significantly lower in learners carrying the MC3R T6K and V81I minor alleles, after adjusting for age, race, gender, and each specific physical activity category. An activity-by-genotype interaction was also detected: learners heterozygous for the V81I polymorphism and performed house chores often had reduced total cholesterol. Though no association was observed between frequency of physical activity and BMI, television viewing was significantly associated with an increase in height, weight and marginally with waist circumference.
Our findings suggest that physical activity even in the form of house chores has a positive effect on metabolic traits and this effect is further enhanced in the presence of MC3R polymorphisms.
Alexis C. Frazier-Wood, Ingrid B. Borecki, Mary F. Feitosa, Paul N. Hopkins, Caren E. Smith and Donna K. Arnett
Time spent in sedentary activities (such as watching television) has previously been associated with several risk factors for cardiovascular disease (CVD) such as increased low-density lipoprotein cholesterol (LDL-C). Little is known about associations with lipoprotein subfractions. Using television and computer screen time in hours per day as a measure of sedentary time, we examined the association of screen time with lipoprotein subfractions.
Data were used from men and women forming the Genetics of Lipid Lowering Drugs and Diet Network (GOLDN) study population. Mixed linear models specified lipoprotein measures as the outcome, and screen time as the predictor for fourteen lipoprotein subfraction measures, and included age, smoking status, pedigree, and fat, carbohydrate daily alcohol and energy intake as covariates. Analyses were run separately for men (n = 623) and women (n = 671). A step-down Bonferroni correction was applied to results. The analysis was repeated for significant results (p < .05), additionally controlling for body mass index (BMI) and moderate and vigorous physical activity.
Linear models indicated that screen time was associated with five lipoprotein parameters in women: the concentration of large VLDL particles (p = .01), LDL particle number (p = .01), concentration of small LDL particles (p = .04), the concentration of large HDL particles (p = .04), and HDL diameter (p = .02). All associations remained after controlling for moderate or vigorous physical activity and BMI.
We show that sedentary time is associated with lipoprotein measures, markers of cardiometabolic disease, independently of physical activity and BMI, in women but not men.
Roy J. Shephard
The pediatric sports physician faces an epidemic of obesity. A preliminary triage of individual patients can be based on the body mass index (BMI). The 80th and 95th percentiles of age-specific BMI suggest overweight and obesity, respectively; the diagnosis is confirmed by measurements of triceps and subscapular skinfolds. Over the last twenty years, the proportions of overweight and obese children have increased in both indigenous populations and most developed societies. The increase in body fat content seems to be associated with a decline in daily energy expenditure. Immediate health consequences include an increased prevalence of atherosclerotic plaques, hypertension, and an adverse lipid profile; in addition, the resulting poor self-image limits sport participation. Many obese children become obese adults, facing increased risks of cardiovascular and all-cause deaths. A combination of increased lifestyle activities, behavioral modification techniques to reduce sedentary behavior, and an appropriate diet seems to be the most effective approach to both prevention and treatment of obesity. Such initiatives should be supported by quality daily physical education and changes in the urban environment that encourage an active lifestyle.
John C. Quindry, Steven R. McAnulty, Matthew B. Hudson, Peter Hosick, Charles Dumke, Lisa S. McAnulty, Dru Henson, Jason D. Morrow and David Nieman
Previous research indicates that ultramarathon exercise can result in blood oxidative stress. The purpose of this investigation was to examine the efficacy of oral supplementation with quercetin, a naturally occurring compound with known antioxidant properties, as a potential countermeasure against blood oxidative stress during an ultramarathon competition. In double-blind fashion, 63 participants received either oral quercetin (250 mg, 4×/day; 1,000 mg/day total) or quercetin-free supplements 3 weeks before and during the 160-km Western States Endurance Run. Blood drawn before and immediately after (quercetin finishers n = 18, quercetin-free finishers n = 21) the event was analyzed for changes in blood redox status and oxidative damage. Results show that quercetin supplementation did not affect race performance. In response to the ultramarathon challenge, aqueous-phase antioxidant capacity (ferric-reducing ability of plasma) was similarly elevated in athletes in both quercetin and quercetin-free treatments and likely reflects significant increases in plasma urate levels. Alternatively, trolox-equivalent antioxidant capacity was not altered by exercise or quercetin. Accordingly, neither F2-isoprostances nor protein carbonyls were influenced by either exercise or quercetin supplementation. In the absence of postrace blood oxidative damage, these findings suggest that oral quercetin supplementation does not alter blood plasma lipid or aqueous-phase antioxidant capacity or oxidative damage during an ultramarathon challenge.