The impact of sarcopenia on a physical activity intervention: the Lifestyle Interventions and Independence for Elders Pilot Study (LIFE-P).

OBJECTIVE: To determine if sarcopenia modulates the response to a physical activity intervention in functionally limited older adults. DESIGN: Secondary analysis of a randomized controlled trial. SETTING: Three academic centers. PARTICIPANTS: Elders aged 70 to 89 years at risk for mobility disability who underwent dual-energy x-ray absorptiometry (DXA) for body composition at enrollment and follow-up at twelve months (N = 177). INTERVENTION: Subjects participated in a physical activity program (PA) featuring aerobic, strength, balance, and flexibility training, or a successful aging (SA) educational program about healthy aging. MEASUREMENTS: Sarcopenia as determined by measuring appendicular lean mass and adjusting for height and total body fat mass (residuals method), Short Physical Performance Battery score (SPPB), and gait speed determined on 400 meter course. RESULTS: At twelve months, sarcopenic and non-sarcopenic subjects in PA tended to have higher mean SPPB scores (8.7±0.5 and 8.7±0.2 points) compared to sarcopenic and non-sarcopenic subjects in SA (8.3±0.5 and 8.4±0.2 points, p = 0.24 and 0.10), although the differences were not statistically significant. At twelve months, faster mean gait speeds were observed in PA: 0.93±0.4 and 0.95±0.03 meters/second in sarcopenic and non-sarcopenic PA subjects, and 0.89±0.4 and 0.91±0.03 meters/second in sarcopenic and non-sarcopenic SA subjects (p = 0.98 and 0.26), although not statistically significant. There was no difference between the sarcopenic and non-sarcopenic groups in intervention adherence or number of adverse events. CONCLUSION: These data suggest that older adults with sarcopenia, who represent a vulnerable segment of the elder population, are capable of improvements in physical performance after a physical activity intervention.

Measured maximal heart rates compared to commonly used age-based prediction equations in the Heritage Family Study.

OBJECTIVE: The purpose of this study was to examine how well two commonly used age-based prediction equations for maximal heart rate (HRmax ) estimate the actual HRmax measured in Black and White adults from the HERITAGE Family Study. METHODS: A total of 762 sedentary subjects (39% Black, 57% Females) from HERITAGE were included. HRmax was measured during maximal exercise tests using cycle ergometers. Age-based HRmax was predicted using the Fox (220-age) and Tanaka (208 - 0.7 × age) formulas. RESULTS: The standard error of estimate (SEE) of predicted HRmax was 12.4 and 11.4 bpm for the Fox and Tanaka formulas, respectively, indicating a wide-spread of measured-HRmax values are compared to their age-predicted values. The SEE (shown as Fox/Tanaka) was higher in Blacks (14.4/13.1 bpm) and Males (12.6/11.7 bpm) compared to Whites (11.0/10.2 bpm) and Females (12.3/11.2 bpm) for both formulas. The SEE was higher in subjects above the BMI median (12.8/11.9 bpm) and below the fitness median (13.4/12.4 bpm) when compared to those below the BMI median (12.2/11.0 bpm) and above the fitness median (11.4/10.3) for both formulas. CONCLUSION: Our findings show that based on the SEE, the prevailing age-based estimated HRmax equations do not precisely predict an individual's measured-HRmax .

Inhalation exposure to cleaning products: application of a two-zone model.

In this study, modifications were made to previously applied two-zone models to address important factors that can affect exposures during cleaning tasks. Specifically, we expand on previous applications of the two-zone model by (1) introducing the source in discrete elements (source-cells) as opposed to a complete instantaneous release, (2) placing source cells in both the inner (near person) and outer zones concurrently, (3) treating each source cell as an independent mixture of multiple constituents, and (4) tracking the time-varying liquid concentration and emission rate of each constituent in each source cell. Three experiments were performed in an environmentally controlled chamber with a thermal mannequin and a simplified pure chemical source to simulate emissions from a cleaning product. Gas phase concentration measurements were taken in the bulk air and in the breathing zone of the mannequin to evaluate the model. The mean ratio of the integrated concentration in the mannequin's breathing zone to the concentration in the outer zone was 4.3 (standard deviation, σ = 1.6). The mean ratio of measured concentration in the breathing zone to predicted concentrations in the inner zone was 0.81 (σ = 0.16). Intake fractions ranged from 1.9 × 10(-3) to 2.7 × 10(-3). Model results reasonably predict those of previous exposure monitoring studies and indicate the inadequacy of well-mixed single-zone model applications for some but not all cleaning events.

Indoor air pollution in developing countries: research and implementation needs for improvements in global public health.

Exposure to indoor air pollution (IAP) from the burning of solid fuels for cooking, heating, and lighting accounts for a significant portion of the global burden of death and disease, and disproportionately affects women and children in developing regions. Clean cookstove campaigns recently received more attention and investment, but their successes might hinge on greater integration of the public health community with a variety of other disciplines. To help guide public health research in alleviating this important global environmental health burden, we synthesized previous research on IAP in developing countries, summarized successes and challenges of previous cookstove implementation programs, and provided key research and implementation needs from structured discussions at a recent symposium.

Interval training in men at risk for insulin resistance.

We compared 3 months of eucaloric (12 kcal/kg/wk) steady state aerobic training (AER) to interval training (INT) in men at risk for insulin resistance. Primary outcomes included oral glucose tolerance testing (OGTT) and HOMA-IR 24 h and 72 h after each participants last exercise session. Secondary outcomes were VO2max, anthropometry, and metabolic syndrome expressed as a summed z-score (zMS). We also performed a sub-analysis for participants entering the trial above and below the HOMA-IR study median. Mean (95% CI) AER ( - 12.81 mg/dl; - 24.7, - 1.0) and INT ( - 14.26 mg/dl; - 24.9, - 3.6) significantly improved 24 h OGTT. HOMA-IR did not improve for AER, but did for INT 24 h and 72 h post-exercise. VO2max improved similarly for both groups. Changes in body mass for INT ( - 2.29 kg; - 3.51, - 1.14), AER, ( - 1.32 kg; - 2.62, 0.58)] and percent body fat [INT, - 0.83%; - 1.62, - 0.03), AER ( - 0.17%; - 1.07, 0.06)] were only significant for INT. When examined as a full cohort, zMS improved for both groups. Upon HOMA-IR stratification, only high HOMA-IR AER showed significant improvements, while both low and high INT HOMA-IR participants demonstrated significant reductions (P<0.05). Eucaloric AER and INT appear to affect fasting glucose, OGTT and VO2max similarly, while INT may have a greater impact on HOMA-IR and zMS.

Effect of astaxanthin on cycling time trial performance.

We examined the effect of Astaxanthin (AST) on substrate metabolism and cycling time trial (TT) performance by randomly assigning 21 competitive cyclists to 28 d of encapsulated AST (4 mg/d) or placebo (PLA) supplementation. Testing included a VO2max test and on a separate day a 2 h constant intensity pre-exhaustion ride, after a 10 h fast, at 5% below VO2max stimulated onset of 4 mmol/L lactic acid followed 5 min later by a 20 km TT. Analysis included ANOVA and post-hoc testing. Data are Mean (SD) and (95% CI) when expressed as change (pre vs. post). Fourteen participants successfully completed the trial. Overall, we observed significant improvements in 20 km TT performance in the AST group (n=7; -121 s; 95% CI, -185, -53), but not the PLA (n=7; -19 s; 95% CI, -84, 45). The AST group was significantly different vs. PLA (P<0.05). The AST group significantly increased power output (20 W; 95% CI, 1, 38), while the PLA group did not (1.6 W; 95% CI, -17, 20). The mechanism of action for these improvements remains unclear, as we observed no treatment effects for carbohydrate and fat oxidation, or blood indices indicative of fuel mobilization. While AST significantly improved TT performance the mechanism of action explaining this effect remains obscure.

Association of white blood cell subfraction concentration with fitness and fatness.

OBJECTIVE: To examine the association between fitness, BMI, and neutrophil, lymphocyte, monocyte, basophil, and eosinophil concentrations in apparently healthy, non-smoking men. DESIGN: Cross-sectional study of 452 men from the Aerobics Center Longitudinal Study examining the resting concentration of white blood cell subfractions across fitness (maximal METs during a treadmill exercise test) and fatness (BMI) categories after adjusting for age. RESULTS: Fitness was inversely associated with all WBC subfraction concentrations. After further adjustment for BMI, only total WBC, neutrophil, and basophil concentrations remained significantly associated with fitness. BMI was directly associated with total WBC, neutrophil, lymphocyte, monocyte, and basophil concentrations and, when fitness was added to the model, only monocytes lost significance. CONCLUSION: Fitness (inversely) and fatness (directly) are associated with WBC subfraction populations.

Obesity, coffee consumption and CRP levels in postmenopausal overweight/obese women: importance of hormone replacement therapy use.

BACKGROUND/OBJECTIVES: Obesity is associated with an inflammatory state that is often characterized by elevated plasma C-reactive protein (CRP) levels. Although coffee is broadly consumed in Western societies, few studies have examined the relationship between obesity, coffee consumption and CRP levels. The objective of this study was to assess the relationship between obesity, coffee consumption and variation in CRP in postmenopausal, overweight/obese women with or without hormone replacement therapy (HRT) use. SUBJECTS/METHODS: Cross-sectional analyses of 344 healthy sedentary, overweight/obese postmenopausal women (mean age=57.1+/-6.4 years and mean body mass index (BMI)=36.1+/-3.9 kg/ m(2)). Plasma CRP levels were measured by a highly sensitive immunoassay that used monoclonal antibodies coated with polystyrene particles. Diet was assessed using the Food Intake and Analysis System semiquantitative food frequency questionnaire. RESULTS: Plasma CRP was positively associated with BMI (P<0.001) and negatively associated with coffee consumption (P

Time trial exertion traits of cycling's Grand Tours.

We examined 26 professional riders during time trial (TT) competitions of the Grand Tours of cycling (Tour de France and Vuelta Espana; 1997-2003) for the exertional characteristics of contending vs. non-contending (i.e., support) riders. We categorized HR time during TT into training impulse (TRIMP) defined from seasonal VO2max testing [Phase I (RCP]. Races were: Short TT (<15 km; 8.9+/-2.9 km); Individual TT (>15 km; 48.12+/-8.7 km); Uphill TT (20.0+/-8.7 km) and Team TT (44.1+/-20.9 km). We observed statistically significant event-by-contender interactions for all TT (all, P<0.0001) except the short TT. During uphill TT, contenders exerted fewer total TRIMP (P<0.01), more Zone 3 TRIMP (P<0.05), and fewer Zone 2 TRIMP (P<0.01) vs. non-contenders. For individual TT, contenders accumulated more Total and Zone 3 TRIMP vs. non-contenders (all, P<0.05). Interestingly, during the team TT, contenders accumulated more Zone 3, and fewer Zone 2 TRIMP (all, P<0.05), despite having the opportunity to draft behind other riders while in paceline race formation. During TT events, contending riders compete at a level of exertion corresponding to a higher metabolic demand during the uphill TT, individual TT and team TT.

Heart rate and exercise intensity during training: observations from the DREW Study.

OBJECTIVE: Cardiovascular drift (CVdrift) is characterised by a continuous, gradual increase in heart rate (HR) after approximately 10 min of moderate-intensity aerobic exercise, despite maintenance of a constant work rate. This has important implications for trials that employ HR to monitor exercise intensity, as reducing work rate in order to keep HR constant could result in participants exercising below the intended intensity. Utilising the Dose Response to Exercise in Women (DREW) database, we sought to determine if increases in HR during exercise (CVdrift) resulted in clinically significant reductions in exercise work rate in order to keep HR within a target range. DESIGN: Randomised, prospective study. SETTING: DREW clinical exercise trail, The Cooper Institute, Dallas, Texas. PARTICIPANTS: Overweight (body mass index 25-43 kg/m2), previously sedentary postmenopausal women (n=326). INTERVENTION: Treadmill and cycling exercise (30-90 min, three to five times per week) at a HR corresponding to 50% of peak oxygen uptake (VO2peak). MAIN OUTCOME MEASURE: Changes in exercise intensity (metabolic equivalents (METS)) during exercise in response to CVdrift. RESULTS: We observed small increases in HR (1-4 beats per minute, p<0.001) combined with small increases in intensity (0.01-0.03 METS, p<0.03) during the combined 12 963 exercise training sessions. Further, we identified only 101 (0.78%) sessions in which intensity was reduced during the course of the exercise session, potentially in response to CVdrift. CONCLUSIONS: We conclude that CVdrift did not contribute to significant reductions in exercise intensity in the DREW study.

Frequency of the VO2max plateau phenomenon in world-class cyclists.

We aimed to determine the frequency of the VO2max plateau phenomenon in top-level male professional road cyclists (n = 38; VO2max [mean +/- SD]: 73.5 +/- 5.5 ml.kg(-1).min(-1)) and in healthy, sedentary male controls (n = 37; VO2max: 42.7 +/- 5.6 ml.kg(-1).min(-1)). All subjects performed a continuous incremental cycle-ergometer test of 1-min workloads until exhaustion. Power output was increased from a starting value of 25 W (cyclists) or 20 W (controls) at the rate of 25 W.min(-1) (cyclists) or 20 W.min(-1) (controls) until volitional exhaustion. We measured gas-exchange and heart rate (HR) throughout the test. Blood concentrations of lactate (BLa) were measured at end-exercise in both groups. We defined maximal exercise exertion as the attainment of a respiratory exchange rate (RER) >or= 1.1; HR > 95 % age-predicted maximum; and BLa > 8 mmo.l(-1). The VO2max plateau phenomenon was defined as an increase in two or more consecutive 1-min mean VO2 values of less than 1.5 ml.kg(-1).min(-1). Most cyclists met our criteria for maximal exercise effort (RER > 1.1, 100 %; 95 % predicted maximal HR [HRmax], 82 %; BLa > 8 mmol.l(-1), 84 %). However, the proportion of cyclists attaining a V.O (2max) plateau was considerably lower, i.e., 47 %. The majority of controls met the criteria for maximal exercise effort (RER > 1.1, 100 %; predicted HRmax, 68 %; BLa > 8 mmol. l(-1), 73 %), but the proportion of these subjects with a VO2max plateau was only 24 % (significantly lower proportion than in cyclists [p < 0.05]). Scientists should consider 1) if typical criteria of attainment of maximal effort are sufficiently stringent, especially in elite endurance athletes; and 2) whether those humans exhibiting the VO2max plateau phenomenon are those who perform an absolute maximum effort or there are additional distinctive features associated with this phenomenon.

Combined aerobic and resistance training in breast cancer survivors: A randomized, controlled pilot trial.

The purpose of this pilot study was to examine the effects of a combined cardiorespiratory and resistance exercise training program of short duration on the cardiorespiratory fitness, strength endurance, task specific functional muscle capacity, body composition and quality of life (QOL) in women breast cancer survivors. Sixteen subjects were randomly assigned to either a training (n = 8; age: 50 +/- 5 yrs) or control non-exercising group (n = 8; age: 51 +/- 10 yrs). The training group followed an 8-week exercise program consisting of 3 weekly sessions of 90-min duration, supervised by an experienced investigator and divided into resistance exercises and aerobic training. Before and after the intervention period, all of the subjects performed a cardiorespiratory test to measure peak oxygen uptake (VO2peak), a dynamic strength endurance test (maximum number of repetitions for chest and leg press exercise at 30 - 35 % and 100 - 110 % of body mass, respectively) and a sit-stand test. Quality of life was assessed using the European Organization for Research and Treatment of Cancer QLQ-C30 (EORTC-C30) questionnaire. In response to training, QOL, VO2peak (mean 3.9 ml/kg/min; 95 % CI, 0.93, 6.90) performance in leg press (17.9 kg; 95 % CI, 12.8, 22.4) and sit-stand test (- 0.67 s; 95 % CI, - 0.52, - 1.2) improved (p < or = 0.05). We observed no significant changes in the control group. Combined cardiorespiratory and resistance training, even of very brief duration, improves the QOL and the overall physical fitness of women breast cancer survivors.

ACTN3 genotype in professional endurance cyclists.

The Z-disk protein alpha-actinin-3 is only expressed in type II muscle fibres, which are responsible for generating forceful contractions at high velocity. Despite the evolutionary conservation of alpha-actinin-3, approximately one in every five Caucasians of European ancestry is totally deficient in this protein, due to homozygosity for a R577X polymorphism in the ACTN3 gene. This, together with the results of recent research on elite athletes, suggests that the "null" XX polymorphism might confer some advantage to endurance performance events. To test this hypothesis, we studied the frequency distribution of R577X genotypes in a group of 50 top-level male professional cyclists (26.9 +/- 0.4 yrs [mean +/- SEM]; VO2max: 73.5 +/- 0.8 ml x kg (-1) x min (-1)). Their results were compared with those of a group of 52 Olympic-class male endurance runners (26.8 +/- 0.6 yrs; VO2max: 73.3 +/- 0.8 ml x kg (-1) x min (-1)) and 123 healthy, sedentary male controls. All subjects were Caucasian, and of European ancestry. No significant differences (p > 0.05) were found between groups: RR: 28.5 %; RX: 53.6 % and XX: 17.9 % in controls; RR: 28.0 %; RX: 46.0 % and XX: 26.0 % in cyclists; and RR: 25.0 %; RX: 57.7 %; XX: 17.3 % in runners). No differences were found in indices of endurance performance (VO2peak or ventilatory thresholds) between athlete carriers of each R577X genotype. In summary, although the alpha-actinin-3 deficient XX genotype may be detrimental for sprint performance in humans, the R577X polymorphism of the ACTN3 gene does not appear to confer an advantage on the ability of male athletes to sustain extreme endurance performance.

Is there an association between ACE and CKMM polymorphisms and cycling performance status during 3-week races?

In this paper, we examine the association between polymorphisms of the angiotensin-converting enzyme (ACE) and muscle-specific creatine kinase (CKMM) genes, and the actual performance status observed in professional cyclists capable of completing a classic tour stage race such as the Giro d'Italia, Tour de France, or Vuelta a España. To accomplish this, we compared the frequencies of the ACE and CKMM genotypes/alleles in 50 top-level Spanish professional cyclists that have completed at least one of these events to 119 sedentary controls, and 27 elite (Olympic-class) Spanish runners. The genetic polymorphism at the CK-MM locus was detected with the NcoI restriction endonuclease. The results of our study showed that the proportion of the DD genotype was higher in cyclists (50.0 %) than in the other two groups (p<0.05), the proportion of the ID genotype was higher in controls (46.2 %) than in the other two groups (p<0.05), and the proportion of the II genotype was higher in runners (40.7 %) than in the other two groups (p<0.05). The proportion of the D allele was higher in both cyclists (65.0 %) and controls (57.6 %) than in runners (46.3 %) (p<0.001), whereas the proportion of the I allele was higher in runners than in the other two groups (p<0.001). No statistical differences were found for CKK-MM- NcoI. We conclude that in top-level professional cyclists capable of completing a classic 3-wk tour race, the frequency distribution of the D allele and the DD genotype seems to be higher than in other endurance athletes such as elite runners (in whom the I allele is especially frequent).

Obesity, macrophage migration inhibitory factor, and weight loss.

OBJECTIVE: Elevated macrophage migration inhibitory factor (MIF) has been implicated as a causal mechanism in a number of disease conditions including cardiovascular disease (CVD), diabetes, and cancer. Excess body fat is associated with an increased risk of numerous health conditions including CVD, diabetes, and cancer. To our knowledge, the association between MIF and obesity status and the effect of weight loss on serum MIF concentrations have not been reported. In this study, we examined the effects of participation in a behavior-based weight loss program on MIF concentrations in obese individuals. SUBJECTS: Study participants were 71 men and women enrolled in The Cooper Institute Weight Management Program. Participants were predominantly female (68%, n=48), middle-aged (46.5+/-9.8 y), and severely obese (BMI=43.0+/-8.6). METHOD: Plasma MIF concentrations and other standard risk factors were measured before and after participation in a diet and physical activity based weight management program. RESULTS: The mean follow-up was 8.5+/-3.0 months with an average weight loss of 14.4 kg (P<0.001). The majority of clinical risk factors significantly improved at follow-up. Median levels of plasma MIF concentration were significantly lower at follow-up (median [IQR]; 5.1[3.6-10.3]) compared to baseline (8.4 [4.3-48.8]; P=0.0005). The percentage of participants with plasma MIF concentration > or =19.5 mg/nl (highest tertile at baseline) decreased from 33.8 to 5.6% (P<0.001). Further, elevated baseline plasma MIF concentration was associated with markers of beta-cell dysfunction and reductions in MIF were associated with improvements in beta-cell function. CONCLUSIONS: Circulating MIF concentrations are elevated in obese but otherwise healthy individuals; however, this elevation in MIF is not uniform across individuals. In obese individuals with elevated circulating MIF concentrations, participation in physical activity and a dietary-focused weight management program resulted in substantial reduction in MIF.

A conceptual framework for performance diagnosis and training prescription from submaximal gas exchange parameters--theory and application.

The first part of this article intends to give an applicable framework for the evaluation of endurance capacity as well as for the derivation of exercise prescription by the use of two gas exchange thresholds: aerobic (AerTGE) and anaerobic (AnTGE). AerT GE corresponds to the first increase in blood lactate during incremental exercise whereas AnTGE approximates the maximal lactate steady state. With very few constraints, they are valid in competitive athletes, sedentary subjects, and patients. In the second part of the paper, the practical application of gas exchange thresholds in cross-sectional and longitudinal studies is described, thereby further validating the 2-threshold model. It is shown that AerTGE and AnTGE can reliably distinguish between different states of endurance capacity and that they can well detect training-induced changes. Factors influencing their relationship to the maximal oxygen uptake are discussed. Finally, some approaches of using gas exchange thresholds for exercise prescription in athletes, healthy subjects, and chronically diseased patients are addressed.

Effects of ribose supplementation prior to and during intense exercise on anaerobic capacity and metabolic markers.

This study examined whether ribose supplementation before and during intense anaerobic exercise impacts anaerobic capacity and metabolic markers. Twelve moderately trained male cyclists (22.3 +/- 2.2 y; 181 +/- 6 cm, 74.8 +/- 9 kg) participated in the study. Subjects were familiarized and fasted for 8 h after standardizing nutritional intake. In a double blind and crossover manner subjects ingested either a 150 mL placebo or ribose (3 g ribose + 150 microg folate). Subjects rested for 25 min and completed 5 x 30 s anaerobic capacity tests with 3 min passive rest. Six capillary blood samples were taken prior to and after sprints for adenine nucleotide breakdown determination. The experiment was repeated 1 wk later with alternative drink. Data were analyzed by repeated measures ANOVA. No significant interactions were observed for any performance or blood variables. D-ribose supplementation has no impact on anaerobic exercise capacity and metabolic markers after high-intensity cycling exercise.