Live high-train low for 24 days increases hemoglobin mass and red cell volume in elite endurance athletes.

The effect of live high-train low on hemoglobin mass (Hbmass) and red cell volume (RCV) in elite endurance athletes is still controversial. We expected that Hb(mass) and RCV would increase, when using a presumably adequate hypoxic dose. An altitude group (AG) of 10 Swiss national team orienteers (5 men and 5 women) lived at 2,500 m (18 h per day) and trained at 1,800 and 1,000 m above sea level for 24 days. Before and after altitude, Hbmass, RCV (carbon monoxide rebreathing method), blood, iron, and performance parameters were determined. Seven Swiss national team cross-country skiers (3 men and 4 women) served as "sea level" (500-1,600 m) control group (CG) for the changes in Hbmass and RCV. The AG increased Hbmass (805+/-209 vs. 848+/-225 g; P<0.01) and RCV (2,353+/-611 vs. 2,470+/-653 ml; P<0.01), whereas there was no change for the CG (Hbmass: 849+/-197 vs. 858+/-205 g; RCV: 2,373+/-536 vs. 2,387+/-551 ml). Serum erythropoietin (P<0.001), reticulocytes (P<0.001), transferrin (P<0.001), soluble transferrin receptor (P<0.05), and hematocrit (P<0.01) increased, whereas ferritin (P<0.05) decreased in the AG. These changes were associated with an increased maximal oxygen uptake (3,515+/-837 vs. 3,660+/-770 ml/min; P<0.05) and improved 5,000-m running times (1,098+/-104 vs. 1,080+/-98 s; P<0.01) from pre- to postaltitude. Living at 2,500 m and training at lower altitudes for 24 days increases Hbmass and RCV. These changes may contribute to enhance performance of elite endurance athletes.     

Effects of 30 days of creatine ingestion in older men

In this investigation we evaluated the effects of oral creatine (Cr) supplementation on body composition, strength of the elbow flexors, and fatigue of the knee extensors in 20 males aged 60-82 years who were randomly administered Cr or placebo (P) in a double-blind fashion. Subjects ingested either 20 g of Cr or P for 10 days, followed by either 4 g of Cr or P, respectively, for 20 days. Tests were conducted pre-supplementation and following 10 and 30 days of supplementation. Leg fatigue was determined using an isokinetic dynamometer; subjects performed 5 sets of 30 maximal voluntary contractions at 180 degrees x s(-1), with 1 min of recovery between sets. The strength of the elbow flexors was assessed using a modified preacher bench attached to a strain gauge. There was a significant interaction (P < 0.05; group x time) in leg fatigue following supplementation. However, this interaction appears to have resulted from a combination of the improved fatigue score by the Cr-supplemented group and the decreased fatigue score by the P-supplemented group, because when the simple main effects were analyzed for the groups individually, there was no significant difference over time for either of the groups. There were no significant differences in body mass, body density, or fat-free mass as assessed by hydrostatic weighing, or strength between the Cr-supplemented or P-supplemented groups. These data suggest that 30 days of Cr-supplementation may have a beneficial effect on reducing muscle fatigue in men over the age of 60 years, but it does not affect body composition or strength.     

Effects of 17 days of head-down bed rest on hydro-electrolytic regulation in men

Prolonged periods of head-down bed rest (HDBR) are commonly used to mimic the effects of microgravity. HDBR has been shown to produce, as in space, a cephalad redistribution of circulating blood volume with an increase in central blood volume which induces the early adaptations in blood volume regulating hormones. Changes in atrial natriuretic peptide (ANP), arginine vasopressin (AVP), renin activity and aldosterone have been observed. Many reports describe these endocrine adaptations but few investigations of rhythms are in the literature. We proposed to evaluate the circadian rhythms of the hormones and electrolytes involved in the hydro-electrolytic regulation during a HDBR study which was designed to simulate a 17-day spaceflight (Life and Microgravity Spacelab experiment, LMS, NASA).     

Modeling active mass in aerobic sludge digestion

Aerobic digestion of waste-activated sludge was carried out in lab-scale reactors for both batch and semicontinuous flow patterns. The reactors were monitored at three different temperatures: 10, 20, and 30 degrees C. During the course of digestion, significant solubilization of volatile suspended solids was observed, and its effect on the magnitude of kinetic coefficients was examined. Differences in metabolic activity and sludge stabilization were found between batch and semicontinuous flow patterns. An Arrhenius-type relationship was not found to apply to rate constants for the semicontinuous reactors.     

Activities of muscle energy supplying enzymes after 5 days complete fasting in young men

The effect of 5 days' complete fasting on the activity of 7 enzymes of energy supplying metabolism was studied in the vastus lateralis muscles of 9 healthy male volunteers. There was a significant decrease of lactate dehydrogenase (by 66%), triosephosphate dehydrogenase (by 61%), malate:NAD dehydrogenase (by 48%), hexokinase (by 40%), 3-hydroxyacyl-CoA-dehydrogenase (by 40%), triosephosphate dehydrogenase/3-hydroxyacyl-CoA-dehydrogenase (by 35%), citrate synthase (by 33%). Glycerolphosphate:NAD dehydrogenase activity did not decrease significantly. These findings suggest a) that utilization of the major energy substrates decreases; b) that the decrease mainly concerns the catabolism of carbohydrates, that of fatty acids to a lesser extent; c) that the decreased capacity of carbohydrate catabolism is partly compensated for by the predominance of the more economic aerobic-oxidative pathway; d) that the reducing equivalents formed in the cytosol may be transported via the glycerolphosphate shuttle into the respiratory chain to a greater extent, so that a greater portion is not lost by the reduction of pyruvate to lactate.     

Effect of iron deficiency anaemia over glycated hemoglobin in non-diabetic women

Background: Glycated hemoglobin (HbA1c) is a form of hemoglobin bound to glucose and used as an index of glycaemic control reflecting glucose levels of the previous three months. Iron deficiency anemia (IDA) is the commonest form of anemia that affects HbA1c. Reports on the effects of IDA on HbA1c levels are inconsistent in India. Therefore, the study correlated the HbA1c and IDA in non-diabetic female patients. Methods: A correlative study between HbA1c and IDA was carried out at the Department of Biochemistry, A. J. Institute of Medical Sciences, Mangaluru, India. A total of 50 non-diabetic female patients, aged between 20-50 years, with decreased levels of Hb, MCV and MCHC were selected. Their ferritin levels were determined by ELISA method to confirm IDA. Forty confirmed iron-deficient samples whose serum ferritin levels were <90 pg/dL, were tested for HbA1c levels by nephelometry method. Results: HbA1c correlated positively with serum ferritin, Hb, MCV, MCH and MCHC (P<0.05). There was a significant decrease in mean value of HbA1c in those with severe anemia (4.50±0.34) compared to those with moderate anemia (5.18±0.35) (P<0.001). Conclusion: Results showed positive correlation of HbA1c with ferritin and hemoglobin. Therefore, iron status should be considered during the interpretation of the HbA1c concentrations in diabetes mellitus.     

Influence of vibration training on energy expenditure in active men

The aim of the present study was to analyze the effect of whole-body vibration on energy expenditure, as well as on exercise intensity, during and immediately after a typical set of exercises for muscle hypertrophy in physically active subjects. Seventeen male university students (mean age 18.3 +/- 0.24 years) volunteered to perform 2 different training exercises: half squat (HS), and half squat with vibration (HSV). Both exercises were performed by all subjects on the vibration platform (with vibration only for HSV), the sequence order being assigned randomly. Energy expenditure (EE), respiratory exchange ratio, perceived exertion (PE), and heart rate were recorded for baseline, exercise, and short-recovery conditions. Training consisted of 5 sets of 10 repetitions of HS and HSV, with a 2-minute recovery interval between sets. Analysis of variance with repeated measurements and Bonferroni correction, as well as effect size were used for statistical calculations. Results indicated that EE and PE were significantly higher in the HSV group, during both exercise and recovery. Heart rate did not differ significantly between groups. Thus, it would appear that HS strength training could be rendered more energy-efficient through the addition of vibration. Moreover, it would be feasible to introduce vibration exercises into regular training programs, particularly those whose key objective is muscle hypertrophy along with fat reduction.     

Prediction of body composition in habitually active middle-aged men.

In 45 physically active men (ages 35-67 yr) who underwent hydrostatic weighing to determine body composition, multiple regression equations were developed for the prediction of body density (D), lean body weight (LBW), fat body weight (FBW), and % fat using selected anthropometric measurements. The prediction accuracy for these parameters using several previously generated anthropometric regression equations was also determined. With equations developed from the present data a substantially higher correlation was obtained between measured and predicted LBW (r = 0.95) than between measured and predicted D (r = 0.85), FBW (r = 0.88), or % fat (r = 0.84). When previously developed equations were applied to the present sample, correlations between measured and predicted values were considerably lower (4-42%) than in the original studies; this reduction was least in the case of LBW. Analysis of previous data indicated that in selected populations total body weight can account for a relatively large fraction of the variance in LBW. LBW may be estimated quite accurately (r greater than or equal to 0.90) in physically active men with one of several regression equations which include total body weight as an independent variable.     

Association between insomnia symptoms and hemoglobin A1c level in Japanese men

Background

The evidence for an association between insomnia symptoms and blood hemoglobin A_1c (HbA_1c) level has been limited and inconclusive. The aim of this study was to assess whether each symptom of initial, middle, and terminal insomnia influences HbA_1c level in Japanese men.

Methods

This cross-sectional study examined 1,022 male workers aged 22–69 years with no history of diabetes at a Japanese company''s annual health check-up in April 2010. High HbA_1c was defined as a blood level of HbA_1c ≥6.0%. Three types of insomnia symptoms (i.e., difficulty in initiating sleep, difficulty in maintaining sleep, and early morning awakening) from the previous month were assessed by 3 responses (i.e., lasting more than 2 weeks, sometimes, and seldom or never [reference group]).

Results

The overall prevalence of high HbA_1c was 5.2%. High HbA_1c was positively and linearly associated with both difficulty in maintaining sleep (P for trend  = .002) and early morning awakening (P for trend  = .007). More specifically, after adjusting for potential confounding factors, high HbA_1c was significantly associated with difficulty in maintaining sleep lasting more than 2 weeks (adjusted odds ratio, 6.79 [95% confidence interval, 1.86–24.85]) or sometimes (2.33 [1.19–4.55]). High HbA_1c was also significantly associated with early morning awakening lasting more than 2 weeks (3.96 [1.24–12.59]).

Conclusion

Insomnia symptoms, particularly difficulty in maintaining sleep and early morning awakening, were found to have a close association with high HbA_1c in a dose-response relationship.     

Burden of infection and fat mass in healthy middle-aged men

Objective: Our aim was to study the effect of exposure to four infections on fat mass. Research Methods and Procedures: This was a cross‐sectional study of healthy middle‐aged men from the general population (n = 74). Each study subject's serum was tested for specific IgG class antibodies against herpes simplex virus (HSV)‐1, HSV‐2, enteroviruses, and Chlamydia pneumoniae through the use of quantitative in vitro enzyme‐linked immunosorbent assays (ELISAs). A total pathogen burden score based on these seropositivities [Quantitative Seropositivity Index (QSI)] was constructed. Fat mass was measured by bioelectrical impedance. Results: We observed significant relationships between the HSV‐1 titer and fat mass and percentage fat mass. The associations were stronger when considering the infection burden. The QSI was significantly associated with fat mass (r = 0.30, p = 0.009) and percentage fat mass (r = 0.27, p = 0.01). Those subjects in the highest tertile of fat mass showed significantly higher QSI (259.5 ± 74.1 vs. 206.9 ± 78.2, p = 0.007). In subjects that were seropositive for Enteroviruses, the relationship between the QSI and fat mass was strengthened (r = 0.51, p = 0.02). In a multivariate regression analysis, the QSI, independently of age and C‐reactive protein, contributed to 9% of fat mass variance. Discussion: Pathogen burden showed an association with fat mass. Subjects with increased fat mass could be more susceptible to developing multiple infections resulting in a chronic low‐grade inflammation. We can not exclude the possibility that exposure to multiple infections leads to increased fat mass.     

Spatial pattern of pulmonary blood flow distribution is stable over days

Glenny, Robb W., Steven McKinney, and H. Thomas Robertson.Spatial pattern of pulmonary blood flow distribution is stableover days. J. Appl. Physiol. 82(3):902-907, 1997.Despite the heterogeneous distribution of regionalpulmonary perfusion over space, local perfusion remains stable overshort time periods (20-100 min). The purpose ofthis study was to determine whether the spatial distribution ofpulmonary perfusion remains stable over longer time periods (1-5days). Regional blood flow was measured each day for 5 days in five awake standing dogs. Fluorescent microspheres of differentcolors were injected into a limb vein over 30 s on each day. After thelast microsphere injection, the dogs were killed, and lungs wereflushed free of blood, excised, dried at total lung capacity, and dicedinto ~2-cm³ pieces(n = 1,296-1,487 per dog).Relative blood flow to each piece on each day was determined byextracting the fluorescent dyes and determining the concentrations ofeach color. We established that blood flow is spatiallyheterogeneous with a coefficient of variation of 29.5 ± 2%. Blood flow to each piece is highly correlated with flow to thesame piece on all days (r = 0.930 ± 0.006). The temporal heterogeneity of regional perfusion as measured by the coefficient of variation is 6.9 ± 0.7% over the 5 days and is nonrandom. The magnitude of spatial and temporal variationis significantly less than previously reported in a study in whichanesthetized and mechanically ventilated dogs were used. We concludethat spatial distribution of pulmonary blood flowremains stable over days and we speculate that in the normal awake dogregional perfusion is determined primarily by a fixed structure such asthe geometry of the pulmonary vascular tree rather than by localvasoactive regulators. Anesthesia and/or mechanical ventilationmay increase the temporal variability in regionalperfusion.

     

Grip strength changes over 27yr in Japanese-American men

The aim of thisstudy was to describe changes in grip strength over a follow-up periodof ~27 yr and to study the associations of rate of strength declinewith weight change and chronic conditions. The data are from theHonolulu Heart Program, a prospective population-based studyestablished in 1965. Participants at exam1 were 8,006 men (ages 45-68 yr) who were ofJapanese ancestry and living in Hawaii. At follow-up, 3,741 men (agerange, 71-96 yr) participated. Those who died before the follow-upshowed significantly lower grip-strength values at baseline than didthe survivors. The average annualized strength change among thesurvivors was 1.0%. Steeper decline (>1.5%/yr) wasassociated with older age at baseline, greater weight decrease, andchronic conditions such as stroke, diabetes, arthritis, coronary heartdisease, and chronic obstructive pulmonary disease. The risk factorsfor having very low hand-grip strength at follow-up, here termedgrip-strength disability (21 kg, the lowest 10th percentile), werelargely same as those for steep strength decline. However, theage-adjusted correlation between baseline and follow-up strength wasstrong (r = 0.557, P < 0.001); i.e., those who showedgreater grip strength at baseline were also likely to do so 27 yrlater. Consequently, those in the lowest grip-strength tertile atbaseline had about eight times greater risk of grip-strength disabilitythan those in the highest tertile because of their lower reserve ofstrength. In old age, maintenance of optimal body mass may help preventsteep strength decrease and poor absolute strength.

     

Precedence of head homoeothermia over trunk homoeothermia in dehydrated men

Three male humans were subjected repeatedly to 20 min exercise on a bicycle ergometer: twice when hydrated normally and twice when dehydrated. Tympanic (Tty) and oesophageal (Tes) temperatures were recorded and sweat rates on forehead and back were measured. Dehydration did not change the forehead sweat rate, but on the back it reduced significantly, resulting in an increase of Tes. However, Tty was decreased by dehydration. 20 min after the end of exercise subjects were allowed to drink water in order to trigger the potohidrotic response. A potohidrotic response was noted on the back of dehydrated subjects only. It is concluded that dehydration results in active inhibition of sweating on the body but not on the forehead, where evaporation is needed for selective cooling of the brain.