Monitoring 6 Weeks of Progressive Endurance Training with Plasma Glutamine

The distinction between positive and negative training adaptation is an important prerequisite in the identification of any marker for monitoring training in athletes. To investigate the glutamine responses to progressive endurance training, twenty healthy males were randomly assigned to a training group or a non-exercising control group. The training group performed a progressive (3 to 6 x 90 minute sessions per week at 70 % V.O (2max)) six-week endurance training programme on a cycle ergometer, while the control group did not participate in any exercise during this period. Performance assessments (V.O (2max) and time to exhaustion) and resting blood samples (for haemoglobin concentration, haematocrit, cortisol, ferritin, creatine kinase, glutamine, uric acid and urea analysis) were obtained prior to the commencement of training (Pre) and at the end of week 2, week 4 and week 6. The training group showed significant improvements in time to exhaustion (p < 0.01), and V.O (2max) (p < 0.05) at all time points (except week 2 for V.O (2max)), while the control group performance measures did not change. In the training group, haemoglobin concentration and haematocrit were significantly lower (p < 0.01) than pretraining values at week 2 and 4, as percentage changes in plasma volume indicated a significant (p < 0.01) haemodilution (+ 6 - 9 %) was present at week 2, 4 and 6. No changes were seen in the control group. In the training group, plasma glutamine (week 2, 4 and 6), creatine kinase (week 2 and 4), uric acid (week 2 and 4) and urea (week 2 and 4) all increased significantly from pretraining levels. No changes in cortisol or ferritin were found in the training group and no changes in any blood variables were present in the control group. Plasma glutamine was the only blood variable to remain significantly above pretraining (966 +/- 32 micromol . 1 (-1)) levels at week 6 (1176 +/- 24 micromol . 1 (-1); p < 0.05) The elevation seen here in glutamine levels, after 6 weeks of progressive endurance training, is in contrast to previous reports of decreased glutamine concentrations in overtrained athletes. In conclusion, 6 weeks of progressive endurance training steadily increased plasma glutamine levels, which may prove useful in the monitoring of training responses.

Quantification of terbutaline in urine by enzyme-linked immunosorbent assay and capillary electrophoresis after oral and inhaled administrations

The International Olympic Committee and World AntiDoping Agency restricts the use of beta2-agonists and only the inhaled administration of terbutaline, salbutamol, formoterol and salmeterol is permitted for therapeutic reasons. The aim of this study was to develop a test for the quantitation of terbutaline in urine and evaluate different parameters to distinguish between oral and inhaled administration of the drug. Urine samples were collected from asthmatic and non-asthmatic recreational swimmers who had received repeated doses of oral (3x2.5 mg plus 1x5 mg during 24 h) and inhaled (12x0.5 mg in 24 h with half of it being in the last 4 h) racemic terbutaline, and single oral (5 mg) or single inhaled doses (1 mg). Total terbutaline concentrations (free+conjugated) were determined by enzyme-linked immunosorbent assay. Results showed that after oral administrations urinary terbutaline concentrations were higher than those detected after inhalation. For confirmation purposes, a chiral capillary electrophoretic procedure was established and validated. A solid-phase extraction with Bond-Elut Certify cartridges was undertaken, separation performed using a 50 mM phosphate buffer (pH 2.5) containing 10 mM of (2-hydroxypropyl)-beta-cyclodextrin as running buffer and diode-array UV detection set at 204 nm. The proposed procedure is rapid, selective and sensitive allowing quantitation of free terbutaline enantiomers in urine. No statistical differences were found between total free terbutaline concentrations [S-(+)+R-(-)] in urine collected after oral and inhaled administrations of the drug. After oral doses enantiomeric [S-(+)]/[R-(-)] ratios lower than those obtained after inhalation were observed probably due to an enantioselective metabolism that take place in the intestine, but differences between both routes of administration were not statistically significant. Although different trends were observed after oral and inhaled doses in total terbutaline, total free terbutaline concentrations and in ratios between its enantiomers, differences observed were not sufficiently significant to establish cut-off values to clearly distinguish between both routes of administration.

The pathophysiology and management of renal bone disease in dialysis patients

As renal function declines, changes in mineral metabolism occur including phosphate retention, calcitriol deficiency, and the development of secondary hyperparathyroidism. Renal bone disease related to disordered mineral metabolism may result in increased patient morbidity and mortality. Uncontrolled parathyroid hormone (PTH) secretion will result in osteitis fibrosa, a high turnover bone disease. The use of calcium and aluminum-based phosphate binders and vitamin D sterols may contribute to the development of low turnover bone diseases such as osteomalacia and aplastic bone disease. Prevention and control of renal bone disease is an important goal for the interdisciplinary health care team. This paper discusses disordered mineral metabolism and its relationship to renal bone disease. Case studies illustrate the development and treatment of renal bone disease related to secondary hyperparathyroidism and aluminum intoxication.

Inflammation, peritoneal transport, and response to erythropoietin in peritoneal dialysis patients

The aim of the present study was to examine the association between 4-hour dialysate-to-plasma ratio of creatinine (D/PCr), erythropoietin (EPO) responsiveness [EPO (U/week)/hemoglobin (g/L)], and C-reactive protein (CRP). Subjects were 54 prevalent peritoneal dialysis (PD) patients [mean age: 58 years; 30 women, 24 men; 28 with diabetes; 15 on continuous ambulatory peritoneal dialysis (CAPD); 39 on continuous cycling peritoneal dialysis (CCPD); mean Kt/V: 2.44]. In 17 patients, CRP was elevated (> 15 mg/L), and in 39 patients, 4-hour D/PCr was high or high-average (> or = 0.65). Mean hemoglobin (Hb) was 115.5 +/- 12.9 g/L; median EPO dose was 2800 U/week, and median EPO/Hb was 24.5. A nonsignificant negative correlation was noted between CRP and hemoglobin (r = -0.25, p = 0.07), but no correlations were seen between CRP and 4-hour D/PCr, or hemoglobin and 4-hour D/PCr. No correlation was seen between EPO/Hb and 4-hour D/PCr or CRP. Multiple linear regression (stepwise, alpha = 0.05) was performed with outcome hemoglobin and independent variables EPO [U/week (forced in)], percent transferrin saturation [TSAT (forced in)], age, sex, diabetes mellitus, serum albumin, CRP, time on PD, 4-hour D/PCr, normalized protein catabolic rate (nPCR), ferritin, intact parathyroid hormone (iPTH), aluminum, and angiotensin converting enzyme inhibitor (ACEI) use. Serum albumin (1.27, p < 0.01) and diabetes mellitus (-6.69, p = 0.04) were the only significant predictors of hemoglobin. With serum albumin removed from the model, age (but not CRP) became significant. These results do not support an association between peritoneal transport and EPO responsiveness, mediated by inflammation. The association between serum albumin and hemoglobin appears to be confounded by age more than by inflammation.

The relationship between dialysate protein loss and membrane transport status in peritoneal dialysis patients

Peritoneal dialysis (PD) patients lose significant quantities of protein and albumin during the dialysis procedure. The losses are greater in high transporters. The aim of the present study was to investigate the relationship between peritoneal membrane transport characteristics and protein losses. We studied 33 PD patients [14 men, 19 women; mean age: 53.5 years (range: 21-80 years)]. Fourteen patients had diabetes, and 22 were on automated PD. Dialysis adequacy was good, with a mean Kt/V of 2.63 (range: 1.51-4.89). Patients underwent a standard peritoneal equilibration test (PET). In addition, dialysate albumin (Alb) and protein (Pro) were measured at 0, 1, 2, and 4 hours, after lack of interference from unspent dialysate was ensured. Of the 33 patients, 23 were high or high-average transporters [based on 4-hour dialysate-to-plasma ratio of creatinine (D/PCr > or = 0.65)]. Protein losses owing to PD ranged from 3.5 g/day to 13.2 g/day (median: 5.9 g/day), of which 1.9-7.14 g/day (median: 3.21 g/day) was albumin. The 4-hour D/PCr correlated with the 4-hour D/PAlb (r = 0.62, p < 0.01), and 4-hour D/PPro (r = 0.63, p < 0.01). This finding persisted after correction for volume, indicating that it was not simply a concentration effect. The 4-hour D/PAlb and 4-hour D/PPro also correlated with the 24-hour PD albumin and protein losses. These results suggest a strong association between D/PCr and D/P for proteins. This observation is consistent with the increased protein losses through PD in high transporters and may be related to the inferior outcomes in this group.

Long-term effects of exercise on blood pressure and lipids in healthy women aged 40-65 years: The Sedentary Women Exercise Adherence Trial (SWEAT)

OBJECTIVES

To evaluate the long-term effects of regular moderate or vigorous intensity exercise on blood pressure and blood lipids in previously sedentary older women.

DESIGN

Subjects were randomly assigned to either a supervised centre-based (CB) or a minimally supervised home-based (HB) exercise program, initially for 6 months. Within each program, subjects were further randomized to exercise either at moderate (40-55% heart rate reserve, HRres) or vigorous intensity (65-80% HRres). After 6 months, all groups continued a HB moderate or vigorous exercise program for another 12 months.

METHODS

Healthy, sedentary women (aged 40-65 years) (n = 126) were recruited from the community. Subjects exercised three times per week for 30 min. They were evaluated at baseline, 6, 12 and 18 months.

RESULTS

There was a significant fall of 2.81 mmHg in systolic blood pressure (P = 0.049) and 2.70 mmHg in diastolic blood pressure (P = 0.004) after correction for age and baseline values with moderate exercise, but not with vigorous-intensity exercise. When this analysis was repeated with the change in body mass included, the results were unchanged. After correction for potential confounding factors, there was a significant fall in total cholesterol and low density lipoprotein cholesterol with vigorous but not moderate exercise at 6 months (P < 0.05) but not at 18 months.

CONCLUSIONS

In this largely normotensive population of older women, a moderate, but not vigorous exercise program, achieved sustained falls in resting systolic and diastolic blood pressure over 18 months. The study demonstrates that, in older women, moderate intensity exercise is well accepted, sustainable long-term and has the health benefit of reduced blood pressure.

Laboratory protocol for exercise asthma to evaluate salbutamol given by two devices

PURPOSE

As new delivery devices and formulations are being introduced for drugs given by inhalation, there is a need to evaluate their equivalence with old preparations. One way to do this is to investigate their equivalence in protecting from exercise-induced asthma (EIA).

METHODS

We used a protocol for EIA to compare the protective effect of salbutamol delivered by the pressurised metered dose inhaler (pMDI) and the new Diskus dry powder device. Twenty-seven asthmatic subjects with moderately severe EIA completed an exercise test on four separate days at two study centers. Exercise was performed by cycling for 8 min while inhaling dry air (0% RH, 20-24 degrees C). The target workload in W was predicted as (53.76 x predicted FEV1) - 11.07 and 95% of this target was achieved at 4 min of exercise. This target was chosen in order to achieve ventilation between 50 and 60% of predicted maximum in the last 4 min.

RESULTS

There was no significant difference in the workload, ventilation, or heart rate achieved on the study days. The severity of EIA was measured as the % fall in FEV1. EIA severity was similar on the placebo and control day and the coefficient of variation was 19.4%. The mean +/- SD % fall on the control, placebo, salbutamol by Diskus, and pMDI were 42.0% +/- 15, 39.4% +/-17.6, 13.4% +/- 13.2, and 8.5% +/- 13.8, respectively. Salbutamol significantly inhibited the % fall in FEV1 after exercise, and there was no difference between the preparations.

CONCLUSION

The protocol described here is suitable for evaluating equivalence of salbutamol preparations in protecting against EIA and could be used to evaluate the protective effect of other medications.

Apolipoprotein(a) phenotype, albumin clearance, and plasma levels of lipoprotein(a) in peritoneal dialysis

This cross-sectional study was undertaken to examine the relationship between plasma lipoprotein(a) [Lp(a)] level and peritoneal dialysis (PD) albumin clearance while controlling for the influence of the apolipoprotein(a) [apo(a)] phenotype. Plasma Lp(a) level, PD albumin clearance, and apo(a) phenotype (high vs. low molecular weight, HMW vs. LMW) were determined in 54 PD patients. Apo(a) phenotypes were 24 LMW and 30 HMW. The plasma Lp(a) level was high (> 65 nmol/l) in 17 of 24 patients with LMW phenotype versus 2 of 30 with HMW phenotype (chi2, p < 0.01). Spearman correlation coefficients of Lp(a) with PD, urine, and total albumin clearances were -0.05 (p = 0.74), -0.04 (p = 0.80), and -0.09 (p = 0.51), respectively. The apo(a) isoform size was the only significant predictor of Lp(a) in multivariate analysis. In this study, there was no association between PD albumin clearance and Lp(a) level. The association between apo(a) phenotype and Lp(a) level is in keeping with studies in the general population. There is a strong genetic influence on Lp(a) level in PD patients.

Randomised trial of personalised computer based information for patients with schizophrenia

OBJECTIVES

To compare use, effect, and cost of personalised computer education with community psychiatric nurse education for patients with schizophrenia.

DESIGN

Randomised trial of three interventions. Modelling of costs of alternatives.

PARTICIPANTS

112 patients with schizophrenia in contact with community services; 67 completed the intervention.

INTERVENTIONS

Three interventions of five educational sessions: (a) computer intervention combining information from patient's medical record with general information about schizophrenia; (b) sessions with a community psychiatric nurse; (c) "combination" (first and last sessions with nurse and remainder with computer).

MAIN OUTCOME MEASURES

Patients' attendance, opinions, change in knowledge, and psychological state; costs of interventions and patients' use of NHS community services; modelling of costs for these three, and alternative, interventions.

RESULTS

Rates of completion of intervention did not differ significantly (71% for combination intervention, 61% for computer only, 46% for nurse only). Computer sessions were shorter than sessions with nurse (14 minutes v 60 minutes). More patients given nurse based education thought the information relevant. Of 20 patients in combination group, 13 preferred the sessions with the nurse and seven preferred the computer. There were no significant differences between groups in psychological outcomes. Because of the need to transport patients to the computer for their sessions, there was no difference between interventions in costs, but computer sessions combined with other patient contacts would be substantially cheaper.

CONCLUSIONS

The computer based patient education offered no advantage over sessions with a community psychiatric nurse. Investigation of computer use combined with other health service contacts would be worth while.

Chlamydia pneumoniae DNA in peripheral blood mononuclear cells in peritoneal dialysis patients

OBJECTIVE

The aim of the present study was to examine the association between infection with Chlamydia pneumoniae and symptomatic atherosclerosis in peritoneal dialysis (PD) patients.

DESIGN

Cross-sectional study.

SETTING

Peritoneal Dialysis Unit of Kingston General Hospital.

PATIENTS

Fifty-five prevalent PD patients.

OUTCOME MEASURES

(1) Infection with C. pneumoniae diagnosed by detection of DNA in peripheral blood mononuclear cells (PBMCs) using polymerase chain reaction. (2) Symptomatic atherosclerosis involving the coronary, cerebral, or peripheral circulation.

RESULTS

The DNA of C. pneumoniae was detected in PBMCs in 33 patients (60.0%). Atherosclerosis was present in 16 of 33 (48%) PBMC C. pneumoniae DNA-positive patients, and in 10 of 22 (45%) PBMC C. pneumoniae DNA-negative patients (p = 0.83). Using multiple logistic regression and controlling for a number of known cardiovascular risk factors, PBMC C. pneumoniae DNA status was not predictive of atherosclerosis. The only significant independent predictors of atherosclerosis were diabetes and age.

CONCLUSIONS

In prevalent PD patients, a high prevalence of symptomatic atherosclerosis and of Chlamydia pneumoniae DNA in PBMCs were seen; however, the results of the present study do not support the presence of an association between infection with C. pneumoniae and atherosclerosis.

Discrimination of prohibited oral use of salbutamol from authorized inhaled asthma treatment

BACKGROUND

The administration of salbutamol is permitted only by inhalation by the International Olympic Committee (IOC) for the management of asthma and exercise-induced asthma in athletes. The establishment of criteria to distinguish between the (IOC) authorized use (inhaled) and the (IOC) prohibited use (oral) of salbutamol appeared possible using simultaneous evaluation of variables based on the concentration of nonconjugated enantiomers of salbutamol excreted in urine.

METHODS

Urine was collected from asthmatic and nonasthmatic swimmers who had received various preexercise doses of oral (five doses of 4 mg) or inhaled (two doses of 100 microgram) salbutamol. Urine was also obtained from subjects who had received the maximum dosage of inhaled salbutamol advisable for competing athletes to provide protection from exercise-induced asthma and treatment of asthma (1600 microgram in 24 h, 800 microgram being in the last 4 h). All samples were analyzed to determine the total amount of unchanged salbutamol excreted in urine and the ratio between the S: and R: enantiomers.

RESULTS

The discriminant function D = -3.776 + 1.46 x 10(-3) ([S:(+)] + [R:(-)]) + 1.012 ([S:(+)]/[R(-)]) can be used to classify data into two groups, inhaled and oral. The confirmatory criterion suggested (cutoff at D = 1.06, 4 SD from the mean D value of the inhaled distribution) has been verified in different sets of samples showing suspicious concentrations by conventional screening procedures in doping control. An 11.8% false-negative (oral classified as inhaled) rate is assumed with the confirmatory criterion proposed, but virtually no false positives (inhaled classified as oral) are obtained (<1 in 33 000).

CONCLUSIONS

The overall procedure recommended is to screen all samples and to apply the confirmation criterion proposed to samples showing free racemic salbutamol concentrations >500 microgram/L by gas chromatography-mass spectrometry or free + conjugated racemic salbutamol concentrations >1400 microgram/L by ELISA.

Distinction of inhaled and oral salbutamol by urine analysis using conventional screening procedures for doping control

Salbutamol administration in athletes is permitted only by inhalation, for the management of asthma. The authors discuss different criteria for suspecting oral use of salbutamol, taking into account the data obtained by application of two conventional screening procedures for doping control: gas chromatography/mass spectrometry (GC/MS) and enzyme-linked immunosorbent assay (ELISA). Urine samples obtained after administration of oral and inhaled salbutamol to asthmatic and nonasthmatic swimmers were analyzed using both analytical approaches. As expected, concentrations obtained by the ELISA test (detection of total salbutamol) were higher than those obtained using the GC/MS procedure (detection of nonsulfated salbutamol). After oral administration, the ELISA test detected significantly higher salbutamol concentrations than those detected after inhalation, reflecting the greater doses administered orally. Urine samples with total salbutamol greater than 1400 ng/mL were obtained after oral doses, but no sample reached this value after inhaled doses. Higher concentrations of nonsulfated salbutamol have also been detected after oral intake, although there is an overlap between the distributions of concentrations after oral and inhaled doses. A cut-off concentration of 500 ng/mL can be used for nonsulfated salbutamol to select suspicious samples, giving 11.8% false negative results and 4.3% false positive results. An additional criterion evaluated was the androsterone-salbutamol peak height ratio, which was lower after oral doses because of the higher concentrations of salbutamol in urine. This ratio was lower than 2 for all the samples collected after oral administration, although 6.8% false positive samples resulted because of low concentrations of androsterone in female urine. Several possibilities for detecting suspicious samples from athletes who have taken prohibited oral salbutamol are available with conventional screening procedures in doping control.

Mouse to elephant: biological scaling and Kt/V

The construct Kt/V is used by the nephrology community in prescribing dialysis dose. The concerns that have been raised as to what value of V to use in the calculation of Kt/V touch on the more central question of whether filtration rate should be normalized by a parameter other than V. Within the animal kingdom, a number of physiological variables scale to body size according to an equation of the form Y = YoMb, where Yo is a constant, M is body mass, and b is a scaling exponent. Glomerular filtration rate (GFR) in mammals weighing from 30 g to 503 kg scales to body weight with an exponent of 0.77. Hence, GFR per unit body weight (or Kt/V) decreases significantly with increasing body size. Metabolic rate also scales to body size in a wide range of mammals according to the same general equation and with a scaling exponent of 0.75. Because GFR and metabolic rate scale to body mass with virtually the same exponent, a ratio of the two yields a constant independent of body size. We propose that the ratio (filtration rate/metabolic rate) replace Kt/V. Such a ratio would underscore the linkage between filtration rate (and dialysis therapy) and the metabolic demands of the body.

The influence of total, dialysis, and residual renal urea clearances on serum albumin in peritoneal dialysis

Though serum albumin (SA) and Kt/V predict mortality in peritoneal dialysis (PD), the relationship between them remains unclear. We report a cross-sectional study of factors associated with SA in PD, and a prospective study of the effect of increasing dialysis dose on SA in hypoalbuminemic patients with Kt/V < 2.1. Multiple linear regression was performed in 56 subjects with dependent variable SA at 4 months after starting PD (SA2), and independent variables: age, sex, diabetes, 4h-D/Pcr, predialysis SA (SA1), nPCR, PD-duration, modality, Kt/V, Ccr, and daily volume excreted normalized to body water (Vt/V). Forward stepwise selection (alpha = 0.05) produced a model (r2 = 0.492, P < 0.001) containing predictors of SA2: SA1 and nPCR (positive), and Vt/V (negative). With Vt/V excluded, Kt/V became significant (negative). Broken into components, dialysate Kt/V was significant, but residual Kt/V was not significant. In 14 hypoalbuminemic patients with Kt/V < 2.1, PD prescription was changed, targeting a Kt/V > 2.1. After 3.3 months, Kt/V rose from 1.7 +/- 0.25 to 2.21 +/- 0.36 (P = 0.0001), and nPCR rose slightly, 0.71 +/- 0.13 to 0.78 +/- 0.19 (P = NS), with no significant change in SA, 30.5 +/- 3.0 g/L to 31.4 +/- 3.8 g/L (P = 0.268). Dialysate and urine volumes are negative predictors of SA. Volume-dependent dialysate-protein loss could account for poor correlation between Kt/V and SA, and lack of improvement in SA with increased Kt/V.

A randomised, controlled study of the effects of aerobic exercise and dietary fish on coagulation and fibrinolytic factors in type 2 diabetics

Type 2 diabetes is associated with disturbances in coagulation and fibrinolysis. Prospective studies show that increased tissue plasminogen activator (tPA) antigen increases the risk of cardiovascular mortality. The present study examined the hypothesis that combining a regime of moderate aerobic exercise with one daily fish meal as part of a low-fat diet (30% total energy) would improve coagulation and fibrinolytic factors in dyslipidaemic type 2 diabetic patients. In a randomised. controlled, 8-week trial, 55 sedentary type 2 diabetic subjects with serum triglycerides >1.8 mmol/l and/or HDL-C <1.0 mmol/l were randomly assigned to a low-fat diet (30% daily energy intake) with or without one fish meal daily (3.6 g omega3 fatty acids/day) and further randomized to a moderate (55-65% VO2max) or light (heart rate <100 bpm) exercise program. Plasma levels of fibrinogen, coagulation factor VIIc, tPA and plasminogen activator inhibitor (PAI-1) antigen were measured before and after intervention. In the 49 subjects who completed the study, the fish diet alone, moderate exercise alone and the combination of fish and moderate exercise all led to significant reductions in tPA antigen concentrations (-2.1 ng/ml, p = 0.02. -1.9 ng/ml, p = 0.03, -2.0 ng/ml, p = 0.01, respectively) compared to controls. In multivariate regression, changes in fasting blood glucose (positively) and erythrocyte omega3 fatty acid composition (inversely) were independent predictors of the change in tPA antigen. The fish diet alone contributed to a significant rise in coagulation factor VIIc compared to controls (4.9%, p = 0.02), which was prevented by moderate exercise. No significant effects on PAI-1 antigen and fibrinogen were seen. In view of recent epidemiological findings, the reduction in tPA antigen with both fish and moderate exercise in these dyslipidaemic type 2 diabetic patients could reflect a reduced thrombotic potential and decreased cardiovascular risk. Furthermore, a small, albeit significant, increase in coagulation factor VIIc associated with fish can be prevented by a concomitant programme of moderate exercise.

The effects of learning on the ventilatory responses to inspiratory threshold loading

Progressive threshold loading (PTL) is frequently used to assess inspiratory muscle endurance in health and disease. We and others have noted a systematic increase in endurance with the first few exposures to the task in subjects previously naïve to PTL, which may not be related to conditioning of the muscles themselves. The purpose of this study was to investigate the mechanisms responsible for this increased endurance by examining the ventilatory responses to 3 PTL tests, each > 24 h apart, in 18 healthy subjects. During PTL, threshold pressure (Pth) was increased by approximately 10% every 2 min until task failure. Subjects were allowed to adopt any breathing pattern. Respiratory muscle strength (maximal inspiratory pressure [PImax]) was unchanged over successive tests while maximal Pth (Pthmax) during PTL increased (69 +/- 17, 77 +/- 16, and 86 +/- 11% of PImax, respectively, p < 0.05) (mean +/- SD), indicating that the increased Pthmax could not be attributed to improved respiratory muscle strength. Breathing pattern changed with successive tests, so that for comparative loads inspiratory time (TI), respiratory frequency (f ), and duty cycle (TI/Ttot) decreased. This change in breathing pattern did not alter respiratory muscle efficiency (respiratory muscle V O2/work), which was similar in each test (2.4 +/- 2.2%), but perceived effort (Borg Score), which was maximal at task failure in each test, decreased at comparative loads with successive tests. Thus, Pthmax during initial tests appeared to be limited by discomfort rather than respiratory muscle function. These findings suggest that the increased Pthmax with successive tests is a consequence of differences in the breathing pattern adopted, reflecting neuropsychological rather than respiratory muscle conditioning. Measurements from PTL should only be used to assess respiratory muscle performance after allowing time for learning.

Cardiac troponin I in patients receiving renal replacement therapy

Current markers of myocardial injury lack specificity in patients with end-stage renal disease (ESRD). In particular, a false positive creatine kinase-MB (CKMB) elevation occurs in 5-10% of patients with ESRD. The aim of this study was to ascertain the relationship between CKMB and cardiac troponin I (cTnI), a new, highly sensitive and specific marker for myocardial injury, in the authors' dialysis population and compare their specificities. Blood samples were obtained from 112 dialysis patients (35 in peritoneal dialysis; 77 in hemodialysis). Patients were asymptomatic for cardiac ischemia and skeletal muscle injury. Mean +/- SD CKMB mass was 3.16 +/- 2.26 microg/L (range, 0.34-13.62), and cTnI was 0.025 +/- 0.061 ng/ml (range, 0.001-0.496). CKMB and cTnI levels did not correlate (r2 = 0.002; p = 0.61). CKMB mass concentration was significantly higher in men and in diabetics. No patient had a cTnI level greater than 1.5 microg/L, and eight asymptomatic patients had a CKMB mass greater than 6.7 microg/L. These data suggest a specificity of 100% for cTnI vs 94.6% for CKMB at these cutoff values. It is suggested that cTnI replace CKMB as a marker of myocardial injury in patients with ESRD.

The case history of an elite ultra-endurance cyclist who developed chronic fatigue syndrome

An elite ultra-endurance athlete, who had previously undergone physiological and performance testing, developed chronic fatigue syndrome (CFS). An incremental cycling exercise test conducted while he was suffering from CFS indicated decreases in maximum workload achieved (Wmax; -11.3%), the maximum oxygen uptake (VO2max; -12.5%), and the anaerobic threshold (AT; -14.3%) compared to pre-CFS data. A third test conducted after the athlete had shown indications of significant improvement in his clinical condition revealed further decreases in Wmax (-7.9%), VO2max (-10.2%) and AT (-8.3%). These data, along with submaximal exercise data and muscle biopsy electron microscopic analyses, suggest that the performance decrements were the result of detraining, rather than an impairment of aerobic metabolism due to CFS per se. These data may be indicative of central, possibly neurological, factors influencing fatigue perception in CFS sufferers.

The influence of exercise-induced plasma volume changes on the interpretation of biochemical parameters used for monitoring exercise, training and sport

A number of studies have demonstrated considerable plasma volume changes during and after exposure to different environmental and physiological conditions. These changes are thought to result from transient fluid shifts into (haemodilution) and out of (haemoconcentration) the intravascular space. If the levels of plasma constituents are to be routinely measured for research purposes or used as indicators of training adaptation or the health of an athlete, then it is important to consider the dynamic nature of plasma volume. Controversy still exists over the relevance of plasma volume interactions with plasma constituent levels, and while some investigators have taken plasma volume shifts into account, others have chosen to ignore these changes. Bouts of acute exercise have been shown to produce a transient haemoconcentration immediately after long distance running, bicycle ergometry and both maximal and submaximal swimming exercise. While these changes are transient, lasting only a few hours, other studies have reported a longer term haemodilution following acute exercise. In addition, endurance training has been shown to cause long term expansion of the plasma volume. It would, therefore, seem important to consider the influence of plasma volume changes on plasma solutes routinely measured for research, and as markers of training adaptation, prior to arriving at conclusions and recommendations based purely on their measured plasma level. To further confound this issue, plasma volume changes are known to be associated with heat acclimatisation, hydration state, physical training and postural changes, all of which may differ from one experiment or exercise bout to the next, and should thus be taken into account.

Classification of compressed breast shapes for the design of equalization filters in x-ray mammography

We are developing an external filter method for equalizing the x-ray exposure in mammography. Each filter is specially designed to match the shape of the compressed breast border and to preferentially attenuate the x-ray beam in the peripheral region of the breast. To be practical, this method should require the use of only a limited number of custom built filters. It is hypothesized that this would be possible if compressed breasts can be classified into a finite number of shapes. A study was performed to determine the number of shapes. Based on the parabolic appearance of the outer borders of compressed breasts in mammograms, the borders were fit with the polynomial equations y = ax2 + bx3 and y = ax2 + bx3 + cx4. The goodness-of-fit of these equations was compared. The a,b and a,b,c coefficients were employed in a K-Means clustering procedure to classify 470 CC-view and 484 MLO-view borders into 2-10 clusters. The mean coefficients of the borders within a given cluster defined the "filter" shape, and the individual borders were translated and rotated to best match that filter shape. The average rms differences between the individual borders and the "filter" were computed as were the standard deviations of those differences. The optimally shifted and rotated borders were refit with the above polynomial equations, and plotted for visual evaluation of clustering success. Both polynomial fits were adequate with rms errors of about 2 mm for the 2-coefficient equation, and about 1 mm for the 3-coefficient equation. Although the fits to the original borders were superior for the 3-coefficient equation, the matches to the "filter" borders determined by clustering were not significantly improved. A variety of modified clustering methods were developed and utilized, but none produced major improvements in clustering. Results indicate that 3 or 4 filter shapes may be adequate for each mammographic projection (CC- and MLO-view). To account for the wide variations in exposures observed at the peripheral regions of breasts classified to be of a particular shape, it may be necessary to employ different filters for thin, medium and thick breasts. Even with this added requirement, it should be possible to use a small number of filters as desired.

Effects of a short-term circuit weight training program on glycaemic control in NIDDM

This study assessed the effects of short-term circuit weight training (CWT) on glycaemic control in NIDDM. Twenty-seven untrained, sedentary subjects (mean age, 51) with NIDDM participated in an 8-week randomised, controlled study, involving either CWT 3 days/week (n = 15) or no formal exercise (control) (n = 12). All subjects performed regular self-blood glucose monitoring throughout. Fasting serum glucose and insulin were measured following a 12-h fast and during an oral glucose tolerance test (75 g) before and after 8 weeks. Twenty-one subjects completed the study (CWT, n = 11) (Control, n = 10). Strength for all exercises improved significantly after CWT. Pooled time-series analysis, using a random effects model, revealed an overall decrease in self-monitored glucose levels with CWT compared to controls. Significant reductions from baseline values were observed in both the glucose (-213 mmol l-1 per 120 min, P < 0.05) and insulin (-6130 pmol l-1 per 120 min, P < 0.05) area under the curve following CWT relative to controls. After adjustment for body mass changes, the change in self-monitored glucose levels and insulin area under the curve, but not glucose area under the curve, remained significant. Short-term CWT therefore may provide a practical exercise alternative in the lifestyle management of this condition.

Role of taste preference on fluid intake during and after 90 min of running at 60% of VO2max in the heat

PURPOSE

The purpose of this study was to determine the relationship between taste preference and total fluid intake during a 90-min run at 60% VO2max as well as during a 90-min period of seated recovery under hyperthermic conditions (30 degrees C, 50% RH), comparing the ad libitum intake of water and two carbohydrate-electrolyte drinks (one containing 6% CHO and the other 8% CHO) randomized over three trails.

METHODS

Fifteen men runners and triathletes, 18 to 40 yr of age, completed an initial test to determine VO2max, a practice 90-min run at 60% VO2max, and three experimental 90-min run/90-min recovery trials on separate days approximately 1 wk apart.

RESULTS

There were no differences across the three treatments in fluid intake, rectal temperature, or RPE during exercise, but subjects consumed 54% and 59% more fluid during recovery with the two carbohydrate-electrolyte drinks compared with water. When comparing the subjects' trials with the most liked versus the least liked of the three fluids, they consumed more of the most liked fluid during exercise (1.10 vs 0.97 L.90 min-1) but not during recovery (1.02 vs 0.90 L.90 min-1.ns).

CONCLUSIONS

Thus, perceived taste of a beverage is important for fluid replacement during exercise.

Impact of portable APD on patient perception of health-related quality of life

We assessed the impact of the introduction of a portable automated peritoneal dialysis (APD) system (Homechoice, Baxter Healthcare) on health-related quality of life (HRQOL). We evaluated HRQOL in 26 patients using the RAND 36-item Health Survey 1.0, which measures physical functioning, role limitations (physical and emotional), social functioning, emotional well-being, pain, energy, and general health perceptions. Questionnaires were administered prior to changing to the new system and 3 months later. Kt/V and albumin levels were measured at both time points. Eight patients had been on continuous ambulatory peritoneal dialysis (CAPD), and 18 had been using other APD systems (PacXtra, Baxter and AMP80, Fresenius). Kt/V increased significantly (p = 0.026); albumin was unchanged (p = 0.09). There was an improvement in the pain score (p = 0.079), although this did not reach statistical significance in the overall sample. Subgroup analysis showed that most of the improvement was from the group that had used the AMP80. No other statistically significant differences were found overall in the domains of HRQOL. Questioning of a random sample of patients indicated that perceived advantages of the new system were ease of setup and portability within the home. Neither of these translated into improvement in role-functioning domains of HRQOL. The improvement in pain score may reflect the capacity of newer cyclers to switch from drain to fill after a set proportion of dialysate has drained, leaving the patient empty for less of the time. Portable APD systems did not bring about predicted improvements in HRQOL. The HRQOL instrument may be insensitive, but technologically convenient advances may have limited impact on HRQOL due to its multifactorial nature.

Significance of prolonged left ventricular wall motion abnormalities after exercise echocardiography following non-Q-wave acute myocardial infarction

Exercise echocardiography was used to assess myocardial ischemia after non-Q-wave acute myocardial infarction in 40 consecutive patients. Resting parasternal long- and short-axis views and apical 4- and 2-chamber views were recorded, digitized, and stored. A maximal symptom-limited exercise test was performed within 21 days (mean 17.7 +/- 3) using a cycle ergometer with continuous monitoring and the echocardiogram was repeated in the same views. Resting and exercise echocardiograms were then compared. Coronary angiography was performed in all patients within 21 days of exercise echocardiography. Stenosis in > or =50% of the lumen diameter was considered significant. Of the 40 patients studied, 29 (72%) had continuing angina and 11 (28%) had no angina. Eighteen patients (62%) with angina developed angina during exercise testing and 19 (65%) developed ST-segment depression. In patients without angina, 1 (9%) developed postexercise angina and 2 (18%) developed ST-segment depression. The mean wall motion score index after exercise increased from 1.2 +/- 0.3 to 1.8 +/- 0.4 in patients with continuing angina (p <0.001) and from 1.2 +/- 0.3 to 1.4 +/- 0.3 in patients without angina (p = NS). Prolonged wall motion abnormalities lasting >20 minutes persisted in > or =1 segment in 27 of 29 patients (93%) with angina or in 2 of 1 1 patients (18%) without angina (p <0.001). Patients with continued angina had predominantly 3-vessel coronary artery disease (22 of 29 [76%]) or 2-vessel disease (7 of 29 [24%]), and those without angina had 1-vessel disease (6 of 11 [55%]) or 2-vessel disease (4 of 11 [36%]). One patient had 3-vessel disease. The duration of wall motion abnormality demonstrated a significant relation to 2- and 3-vessel coronary artery disease (p <0.001). Thus, patients with non-Q-wave acute myocardial infarction had a high incidence of multivessel coronary disease not necessarily detected on routine exercise testing. There was also a significant incidence of prolonged wall motion abnormality.

Training adaptation and biological changes among well-trained male triathletes

The distinction between training and overtraining responses is an important prerequisite for any potential marker for monitoring overtraining in athletes. In this study, eight well-trained male triathletes undertook physical performance assessments, at 6 weekly intervals, throughout a 9-month intensive training season. At each assessment, a resting blood sample was obtained for determination of a number of biological parameters previously associated with overtraining. All athletes produced significant (P < 0.05) improvements in running speed at anaerobic threshold (ATRS) from 15.6 +/- 0.2 k.h-1 at the start of the season to 16.6 +/- 0.6 k.h-1 at the time of major competitions. This improvement in performance was taken as evidence of well balanced training programs. Significant changes (P < 0.05) in plasma glutamine and plasma uric acid concentrations were observed during the training season, and both correlated moderately with ATRS (r = 0.365 and r = -0.328, respectively). None of the other parameters measured showed any significant changes during the training season. The elevations in plasma glutamine concentration observed in response to long-term balanced training may be distinguishable from previous reports of decreased glutamine concentrations in overtrained athletes, making it a potentially valuable tool in the monitoring of overtraining in athletes.

Influence of exercise-induced plasma volume changes on the interpretation of biochemical data following high-intensity exercise

OBJECTIVE

To assess the effects that exercise-induced plasma volume changes (PVCs) have on the interpretation of biochemical and hormonal parameters in the blood of athletes after high-intensity exercise. It was hypothesized that two unrelated high-intensity exercise protocols, performed by two separate subject groups each using different exercise modes, would result in similar percentage changes in plasma volume (% delta PV). It was further hypothesized that the % delta PV, measured in both protocols, would comparably influence the interpretation of biochemical variables measured following exercise.

DESIGN

An experimental before-after trial on volunteers was performed. Two different exercise modes employing two different high-intensity acute exercise protocols were investigated. Eight male swimmers performed an interval training session (ITS) consisting of 15 x 100-m freestyle efforts at 95% of their maximal exercise intensity, and eight male runners performed a multistage discontinuous treadmill test (MSD) to volitional exhaustion.

SETTING

The Human Performance Laboratory at the Department of Human Movement at the University of Western Australia.

MAIN OUTCOME MEASURES

Blood samples obtained before, immediately after, and 30, 60, and 120 min during recovery were analyzed for plasma volume changes, urea, uric acid, creatinine, albumin, calcium, iron, transferrin, testosterone, cortisol, and sex hormone-binding globulin (SHBG).

MAIN RESULTS

The ITS and MSD protocols produced similar and significant alterations (p < 0.01) in plasma volume. Both protocols also elicited significant fluctuations (p < 0.01) in the concentration of most of the parameters measured (excluding iron). When albumin, transferrin, testosterone, and SHBG values were adjusted for the significant % delta PV, their concentrations did not change over the experimental period, suggesting that the changes in measured concentration of these parameters may be, in part, due to changes in plasma volume. However, urea, uric acid, creatinine, calcium, and cortisol, when corrected for % delta PVC, still demonstrated significant changes (p < 0.01).

CONCLUSIONS

It is recommended, when sampling biochemical and hormonal parameters in blood following an acute bout of exercise, that corrections for PVCs should be conducted. Apparent changes in blood solutes may reflect PVCs. PVCs should be taken into consideration when interpreting results regardless of exercise protocol and exercise mode performed.

The influence of blood volume changes on leucocyte and lymphocyte subpopulations in elite swimmers following interval training of varying intensities

The effect that exercise induced blood volume (BV) changes may have on the concentrations of leucocyte and lymphocyte subpopulations following exercise is controversial. Eight nationally ranked swimmers undertook 15 x 100 m swimming intervals (ITS) at 70% and 95% of maximal exercise intensity separated by 2 min recovery periods. Venous blood samples were collected prior to exercise (PRE), immediately post exercise (POST) and at 30, 60, 120 and 150-min post exercise. Control samples were taken on a rest day (R). Only the 95% ITS induced a significant (p < 0.01) reduction in PV (-7.3 +/- 1.1%) and BV (-4.0 +/- 0.6%) POST as calculated according to changes in haemoglobin and haematocrit. Total leucocyte and subset numbers (neutrophils, lymphocytes, monocytes), with the exception of eosinophils, increased significantly (p < 0.01) POST following the 95% ITS, and total leucocyte and neutrophils remained elevated (30% and 114% respectively) (p < 0.01) while lymphocytes progressively decreased by 36% (p < 0.01) at 150-min after exercise. The 70% ITS elicited a decrease (30%) (p < 0.01) only in lymphocyte cell numbers at 60 and 120-min post exercise. The 95% ITS induced significant increases (p < 0.01) in most lymphocyte cell subsets [CD19+ (27%); CD16+ (525%); CD16+ CD25+ (58%); CD4+ (48%); CD8+ (65%)] POST, with a significant reduction (32%) (p < 0.01) in the CD4+:CD8+ lymphocyte ratio. Numbers of CD19+; CD16+; CD5+; CD4+ and CD8+ lymphocytes, while not significantly changed POST following the 70% ITS, were significantly depressed (p < 0.01) during the recovery period. No significant changes were seen in leucocyte or lymphocyte subset numbers during R. All measured leucocyte and lymphocyte subset cell numbers at each ITS were corrected for changes in BV, and there were no significant differences between measured or BV corrected values for any of the cell populations at either of the ITS. Results suggest that while high intensity swimming exercise stress caused significant changes in the numbers and proportions of leucocytes, lymphocytes and their sub-classes, BV changes did not contribute significantly to the changes which occurred. The cell changes therefore, were truly representative of cell movements into and out of the peripheral blood circulation.

The independent and combined effects of aerobic exercise and dietary fish intake on serum lipids and glycemic control in NIDDM. A randomized controlled study

OBJECTIVE

The triglyceride-lowering effects of omega-3 fats and HDL cholesterol-raising effects of exercise may be appropriate management for dyslipidemia in NIDDM. However, fish oil may impair glycemic control in NIDDM. The present study examined the effects of moderate aerobic exercise and the incorporation of fish into a low-fat (30% total energy) diet on serum lipids and glycemic control in dyslipidemic NIDDM patients.

RESEARCH DESIGN AND METHODS

In a controlled, 8-week intervention, 55 sedentary NIDDM subjects with serum triglycerides > 1.8 mmol/l and/or HDL cholesterol < 1.0 mmol/l were randomly assigned to a low-fat diet (30% daily energy intake) with or without one fish meal daily (3.6 g omega-3/day) and further randomized to a moderate (55-65% VO2max) or light (heart rate < 100 bpm) exercise program. An oral glucose tolerance test (75 g), fasting serum glucose, insulin, lipids, and GHb were measured before and after intervention. Self-monitoring of blood glucose was performed throughout.

RESULTS

In the 49 subjects who completed the study, moderate exercise improved aerobic fitness (VO2max) by 12% (from 1.87 to 2.07 l/min, P = 0.0001). Fish consumption reduced triglycerides (0.80 mmol/l, P = 0.03) and HDL3 cholesterol (0.05 mmol/l, P = 0.02) and increased HDL2 cholesterol (0.06 mmol/l, P = 0.01). After adjustment for age, sex, and changes in body weight, fish diets were associated with increases in GHb (0.50%, P = 0.05) and self-monitored glucose (0.57 mmol/l, P = 0.0002), which were prevented by moderate exercise.

CONCLUSIONS

A reduced fat diet incorporating one daily fish meal reduces serum triglycerides and increases HDL2 cholesterol in dyslipidemic NIDDM patients. Associated deterioration in glycemic control can be prevented by a concomitant program of moderate exercise.

Acute intensive interval training and in vitro t-lymphocyte function

Five male endurance-trained runners completed an interval running session of 15 x 1-min intervals at 95% VO2 max. Venous blood samples were collected pre-exercise and then immediately, 30- and 60-minutes post-exercise. The response of cultures of total lymphocytes to mitogen (phytohaemagglutinin) were significantly reduced immediately after exercise, but returned to resting levels by 30-min of recovery. Conversely, the mitogen response of cultures of pure T-lymphocytes (CD4+ and CD8+ cells), separated using a magnetic separation technique, showed no significant change during the exercise and recovery periods. These data showed directly that there was no apparent change in the functional capability of T-lymphocytes following an intensive interval training session. Furthermore, there were significant changes in the composition of the total lymphocyte cultures immediately post-exercise; increased numbers of natural killer (NK) cells (CD56+) and T-suppressor cells (CD8+) and decreased numbers of T-helper cells (CD4+). There were also significant correlations between total mitogen response and the composition of the cultured lymphocytes. These data indicated that the large increases in NK cells, relative to T-cells, following intensive exercise, were the most likely cause of the reduced mitogen response of total lymphocyte cultures.

Is salmeterol ergogenic?

OBJECTIVE

To assess the effects of 50 micrograms of inhaled salmeterol on pulmonary function, selected physical capacities, and fine motor control in 16 nonasthmatic male cyclists and triathletes, mean age of 23.2 (SD = 3.5) years.

DESIGN

Randomized double-blind placebo-controlled crossover trial.

SETTING

Human Physical Performance Laboratory, the University of Western Australia.

SUBJECTS

Sixteen healthy male high-performance nonasthmatic athletes with a mean age of 23.2 years participated in the study.

INTERVENTION

Subjects attended three experimental testing sessions at which salmeterol (50 micrograms), a placebo, or "no treatment" was administered in random order in a double-blind fashion, on separate occasions, prior to exercise.

MAIN OUTCOME MEASURES

During each testing, session lung function was measured before and 10 min after the treatment. Tests of reaction time and hand steadiness and then two anaerobic cycle tests followed. The first, a 10-s all-out sprint was followed, after a 3-min rest, by a 30-s all-out sprint performed on a front access bicycle ergometer. After 10 min recovery, leg flexion-extension peak torque was measured on a Biodex isokinetic dynamometer at speeds of 120 and 180 degrees s-1.

MAIN RESULTS

Lung function variables, reaction time, movement time, alactic anaerobic power, lactacid anaerobic power, and leg-flexion and leg-extension muscular strength were similar among the three treatment groups.

CONCLUSIONS

The preexercise administration of 50 micrograms of inhaled salmeterol has no performance-enhancing effects in nonasthmatic athletes. We believe that athletes with asthma should be permitted to use salmeterol before competition.

Quantity of dialysis: quality of life--what is the relationship?

Health related quality of life (HRQOL) is increasingly being used to evaluate physical and psychosocial parameters in patients receiving dialysis. In patients with chronic illness, these indices are important adjuncts to biochemical measurements. Inadequate dialysis with low urea clearance (Kt/Vurea) has been linked to adverse outcomes in dialysis patients. Little is known about the relationship between dialysis adequacy and patient reported HRQOL. We evaluated HRQOL in 55 hemodialysis and 60 peritoneal dialysis patients using the RAND 36 Item Health Survey 1.0, measuring the following: physical functioning; role limitations (physical); role limitations (emotional); social functioning; emotional well being; pain; energy; and general health perceptions. Kt/V was also calculated for each patient. Mean HD Kt/V was 1.44 +/- 0.31 (range, 0.5-2.0); mean weekly PD Kt/V was 2.28 +/- 0.90 (range, 1.13-6.02). The relationship between Kt/V and HRQOL was tested using Pearson's correlation. No significant association was found for either treatment group between Kt/V and any of the domains of HRQOL. Thus, HRQOL seems to be influenced by factors other than dialysis adequacy, enhancing its role as an independent measure of patient problems otherwise undetected by traditional objective parameters.

Exercise and weight control in sedentary overweight men: effects on clinic and ambulatory blood pressure

OBJECTIVE

To examine whether restriction of caloric intake and exercise of vigorous intensity can independently and additively influence clinic and ambulatory blood pressures in sedentary overweight men.

DESIGN

Sixty subjects aged 20-50 years were randomly allocated either to continue their normal caloric intake or to restrict it by 4186-6279 kl/day, with 15% provided by protein, 30% by fat and 55% by carbohydrate, for 16 weeks. Within each of these groups subjects were further randomly allocated either to a control light intensity programme of exercise or to a vigorous intensity programme of exercise for 30 min three times a week. The light exercise group performed stationary cycling against no resistance, flexibility exercises and slow walking. The vigorous intensity group cycled on an ergometer at 60-70% of maximum their workload.

RESULTS

Fifty-one subjects completed the study. Their maximal oxygen uptake was increased by approximately 24% with vigorous exercise but did not change with light exercise. Caloric intake restriction led to a significant loss of body mass of 9.5 kg (95% confidence interval 7.6-11.3), whereas vigorous exercise had no effect. Restriction of caloric intake reduced supine clinic systolic and diastolic blood pressures significantly by 5.6 (2.3-8.9) and 2.4 mmHg (0.4-4.2), respectively. Relative to the control light exercise group, exercise of vigorous intensity exercise had no significant effect on clinic blood pressure. In contrast, time series analysis revealed that both caloric intake restriction and vigorous exercise were associated with lower daytime ambulatory systolic blood pressure, the reduction in systolic blood pressure being sustained throughout the 24 h period when vigorous exercise and caloric intake restriction were combined.

CONCLUSION

Compared with the effects of caloric intake restriction, the effects of a vigorous exercise programme on blood pressure are inconsistent, there being no influence on clinic blood pressure but a reduction in daytime ambulatory blood pressure. However, when combined with caloric intake restriction, regular vigorous exercise exhibits a synergistic effect in reducing ambulatory blood pressure throughout a 24 h period.

Self-delivery of hemodialysis care: a therapy in itself

Patient autonomy, sense of control, and well-being are thought to be enhanced by self-care hemodialysis as a therapy for end-stage renal disease. Dialysis in a satellite setting reduces travel time and can diminish therapy intrusiveness. Health-related quality of life (HRQOL), in terms of functional status and well-being, was measured in a group of patients trained for self-care, and then measured again after these patients were transferred to a satellite unit. Comparison was made with an age- and comorbidity-matched cohort of full-care patients. Patients trained for self-care tended to score higher than the full-care patients in the psychosocial domains of HRQOL, such as role function, social function, and emotional well-being, before and after transfer to the satellite unit. Physiological measurements did not differ significantly between groups at any time during the study, indicating that differences in HRQOL were not attributable to differences in metabolic stability. We conclude that patients trained for self-care hemodialysis experience better subjective quality of life than their full-care counterparts. This study highlights both the usefulness of measuring HRQOL as an outcome of hemodialysis therapy and the potential benefits of therapies such as self-care and satellite dialysis.

A specific activity questionnaire to measure the functional capacity of cardiac patients

Exercise testing is often performed in persons with cardiac disease to measure their functional capacity. Physical activity questionnaires assessing functional capacity have been used a low-cost and convenient alternative to exercise testing, but have not been well validated against measured oxygen consumption in a cardiac population. This study assesses the ability of a simple, 13-item activity questionnaire, known as the Specific Activity Questionnaire (SAQ), to measure functional capacity prospectively in a large sample of cardiac patients. Ninety-seven consecutive cardiac outpatients (85 men and 12 women aged 59 +/- 10 years [mean +/- SD]) completed the SAQ before an elective symptom-limited treadmill test. Subjects returned within 10 days to repeat the treadmill test, following the same protocol, with the additional measurement of peak oxygen consumption, VO2 (ml x kg(-1)min(-1)), using open circuit spirometry. The SAQ score was significantly related to measured peak VO2(r=0.57, p<0.001). Stepwise multiple linear regression analysis found that the addition of patient age, height, and body weight to SAQ score improved the measurement of peak VO2, accounting for 51% of the sample variance (R=0.71, p<0.001). Peak VO2 was obtained from the following regression formula: [formula: see text]. Thus SAQ, a simple 13-item self-administered activity questionnaire, is able to provide a moderately good measure of functional capacity in cardiac patients and may be useful tool in studies of the cardiac population when formal exercise testing is impractical or uneconomical.

Determinants of change in blood pressure during S.W.E.A.T.: the sedentary women exercise adherence trial

1. In a long-term study of the optimal approach to initiating and maintaining a regular exercise programme in previously sedentary older women (40-65 years), we have assessed determinants of change in resting blood pressure (BP) after 6 and 12 months. 2. Women (n = 126) were randomly assigned to either a centre-based or home-based exercise programme for an initial 6 months. The centre-based group attended supervised sessions three times per week, while the home-based group exercised unsupervised at home three times per week. Both groups were home-based during a second 6 months. Within each arm, subjects were further randomized to either exercise at moderate intensity (40-55% heart rate reserve; HRres) or at vigorous intensity (65-80% HRres). A nonintervention comparison group of 30 women was followed throughout. 3. At 6 months there was a fall in BP with moderate, but not vigorous intensity exercise (-2.7 mmHg; P = 0.025), an effect no longer significant at 12 months. 4. Change in BP was unrelated to improvements in fitness (VO2max), increases in lean tissue mass, number of exercise sessions completed or a composite measure of the total number of exercise sessions completed multiplied by the mean exercise intensity expressed as a percentage of heart rate reserve (%HRres). 5. Continuing participation in any regular exercise was a consistent predictor of change in BP, with those subjects still exercising in the 2 weeks before BP measurement having 1.9 mmHg lower BP at 6 months (P = 0.038) and 3.8 mmHg lower BP at 12 months (P = 0.016). 6. We conclude that the small effects of exercise on resting BP in these older women are predominantly related to continuing participation in lower intensity exercise, rather than to improvements in fitness or body composition.

Assessment of health status in peritoneal dialysis patients: a potential outcome measure

OBJECTIVES

To determine the feasibility and practicality of measuring general health status (GHS) in an outpatient peritoneal dialysis population. To determine whether GSH correlated intuitively with biochemical, socio-demographic and co-morbidity measurements.

DESIGN

The Medical Outcomes Study 20-item short form was administered on a voluntary basis in the outpatient setting. Demographic and current biochemical data were extracted from the medical record. The effects of the socio-demographic, biochemical and physiologic variables on the six subscales of GHS generated by the questionnaire were estimated using multivariate linear regression analysis resulting in the development of six separate models.

SETTING

Peritoneal dialysis program of a University Hospital.

PATIENTS

Sixty stable patients on home peritoneal dialysis completed the GHS questionnaire during regularly scheduled outpatient visits. Ages ranged from 13 to 81 years. The study group included 14 diabetics (23%).

RESULTS

Administering the questionnaire caused no logistical difficulties in the outpatient setting. Regression models for predicting GHS were both significant and intuitively correct. The presence of co-morbidities such as diabetes mellitus (p = 0.002; Social Subscale) and peripheral vascular disease (p = 0.016: General Health Subscale) had the most significant negative impact on GHS. An increased length of time on dialysis was associated with a higher GHS (p = 0.002; Physical Subscale).

CONCLUSION

General Health Status questionnaires can be readily administered to peritoneal dialysis patients in the outpatient setting. They have face validity as a measurement of wellness and functioning. The longitudinal use of such instruments in conjunction with clinical and laboratory findings may identify both medical and non-medical factors impacting on our peritoneal dialysis population.

The emerging role of glutamine as an indicator of exercise stress and overtraining

Glutamine is an amino acid essential for many important homeostatic functions and for the optimal functioning of a number of tissues in the body, particularly the immune system and the gut. However, during various catabolic states, such as infection, surgery, trauma and acidosis, glutamine homeostasis is placed under stress, and glutamine reserves, particularly in the skeletal muscle, are depleted. With regard to glutamine metabolism, exercise stress may be viewed in a similar light to other catabolic stresses. Plasma glutamine responses to both prolonged and high intensity exercise are characterised by increased levels during exercise followed by significant decreases during the post-exercise recovery period, with several hours of recovery required for restoration of pre-exercise levels, depending on the intensity and duration of exercise. If recovery between exercise bouts is inadequate, the acute effects of exercise on plasma glutamine level may be cumulative, since overload training has been shown to result in low plasma glutamine levels requiring prolonged recovery. Athletes suffering from the overtraining syndrome (OTS) appear to maintain low plasma glutamine levels for months or years. All these observations have important implications for organ functions in these athletes, particularly with regard to the gut and the cells of the immune system, which may be adversely affected. In conclusion, if methodological issues are carefully considered, plasma glutamine level may be useful as an indicator of an overtrained state.

Serum free cortisol responses to a standard exercise test among elite triathletes

Eighteen elite male triathletes completed an incremental treadmill run to volitional exhaustion, followed by two maximal cycle ergometer sprints. Venous blood samples were obtained at rest (R), immediately post- (P) and one hour postexercise (H). Serum was analysed for total cortisol (TC) by a radioimmunoassay, and free cortisol (FC) by a temperature and time dependent ultrafiltration/dialysis method. Mean (+SE) resting cortisol levels were 627 + or - 23 (TC) and 12.5 + or - 2.5 nmol 1(-1)(FC). The mean percentage increase in TC (P vs. R) was 49.0 + 73%, accompanied by a 344 + or - 47% increase in FC. Significantly divergent (p<0.001) total cortisol responses (H vs. P) were observed within the group, and the athletes were divided into two subgroups (A and B) on this basis. In group A, both TC and FC returned to resting levels. In group B, there was a further slight increase in TC, accompanied by a significant (p<0.01) increase in FC reaching 851 + or - 268% of resting levels. These data suggest that exercise-induced increases in free cortisol, and hence its catabolic effect, are of much greater relative magnitude than TC changes. The relationship between TC and FC was best fitted to an exponential regression, with a clearcut change in slope at 700 nmol 1(-1)(TC) suggesting saturation of the binding protein. We suggest that the measurement of cortisol in athletes be reassessed, favouring determination of FC in the future.

Comparison of maximal oxygen consumption with oral and nasal breathing

The major cause of exercise-induced asthma (EIA) is thought to be the drying and cooling of the airways during the 'conditioning' of the inspired air. Nasal breathing increases the respiratory system's ability to warm and humidity the inspired air compared to oral breathing and reduces the drying and cooling effects of the increased ventilation during exercise. This will reduce the severity of EIA provoked by a given intensity and duration of exercise. The purpose of the study was to determine the exercise intensity (%VO2 max) at which healthy subjects, free from respiratory disease, could perform while breathing through the nose-only and to compare this with mouth-only and mouth plus nose breathing. Twenty subjects (11 males and 9 females) ranging from 18-55 years acted as subjects in this study. They were all non-smokers and non-asthmatic. At the time of the study, all subjects were involved in regular physical activity and were classified, by a physician, as free from nasal polyps or other nasal obstruction. The percentage decrease in maximal ventilation with nose-only breathing compare to mouth and mouth plus nose breathing was three times the percentage decrease in maximal oxygen consumption. The pattern of nose-only breathing at maximal work showed a small reduction in tidal volume and large reduction in breathing frequency. Nasal breathing resulted in a reduction in FEO2 and an increase in FECO2. While breathing through the nose-only, all subjects could attain a work intensity great enough to produce an aerobic training effect (based on heart rate and percentage of VO2 max).

Depression of plasma glutamine concentration after exercise stress and its possible influence on the immune system

OBJECTIVE

To determine whether plasma glutamine levels can be used as an indicator of exercise-induced stress, and to consider the possible effects of low plasma glutamine concentrations on the immune system.

METHODS

We used two exercise regimens: in Trial 1 seven male subjects were randomly stressed on a treadmill at 0, 30%, 60%, 90% and 120% of their maximal oxygen uptake (VO2max); in Trial 2 five highly trained male subjects underwent intensive interval training sessions twice daily for ten days, followed by a six-day recovery period.

RESULTS

Plasma glutamine concentrations decreased significantly from an average of 1244 +/- 121 mumol/L to 702 +/- 101 mumol/L after acute exercise at 90% VO2max (P < 0.05) and to 560 +/- 79 mumol/L at 120% VO2max (P < 0.001). Four of the five subjects showed reduced plasma glutamine concentrations by Day 6 of the overload training trial, with all subjects displaying significantly lower glutamine levels by Day 11. However, glutamine levels showed a variable rate of recovery over the six-day recovery period, with two subjects' levels remaining low by Day 16.

CONCLUSIONS

Reduced plasma glutamine concentrations may provide a good indication of severe exercise stress.

The haematological, biochemical and immunological profile of athletes suffering from the overtraining syndrome

To help clarify the overtraining syndrome (OTS), a combination of parameters were measured in ten athletes who were suffering from OTS. Blood samples were obtained at rest and a range of haematological, biochemical and immunological tests were carried out on the samples. For each parameter, the mean value for the group was compared to an established normal range amongst age-matched controls. The subjects were also asked to complete a questionnaire to establish the severity of their condition. The data indicated that the debilitating fatigue experienced by the OTS sufferers was not related to any of the blood parameters traditionally associated with chronic exercise stress, since levels were normal in OTS. The only parameter measured which deviated significantly from the normal range for both the sedentary controls and the athletes was the plasma concentration of glutamine. Although the data in this study would suggest that plasma glutamine concentrations represented an objective, measurable difference between OTS subjects and normal controls, it remains to be shown that there is any correlation between glutamine concentrations and other clinical symptoms of OTS such as physical capability.

Psychological and immunological correlates of acute overtraining

Five men undertook two intensive interval training sessions per day for 10 days, followed by 5 days of active recovery. Subjects supplied a venous blood sample and completed a mood-state questionnaire on days 1, 6, 11 and 16 of the study. Performance capabilities were assessed on days 1, 11 and 16 using a timed treadmill test to exhaustion at 18 kmh-1 and 1% grade. These individuals became acutely overtrained as indicated by significant reductions in running performance from day 1 to day 11. The overtrained state was accompanied by severe fatigue, immune system deficits, mood disturbance, physical complaints, sleep difficulties, and reduced appetite. Mood states moved toward baseline during recovery, but feelings of fatigue and immune system deficits persisted throughout the study.