Biomedical subjects

L Szmedra

Publications and source records attributed to L Szmedra.

12 recordsLinked to original sources

PubMed2001

Self-reported symptoms and exercise-induced asthma in the elite athlete.

PURPOSE: The purpose of this study was to compare self-reported symptoms for exercise-induced asthma (EIA) to postexercise challenge pulmonary function test results in elite athletes. METHODS: Elite athletes (N = 158; 83 men and 75 women; age: 22 +/- 4.4 yr) performed pre- and post-exercise spirometry and were grouped according to postexercise pulmonary function decrements (PFT-positive, PFT-borderline, and PFT-normal for EIA). Before the sport/environment specific exercise challenge, subjects completed an EIA symptoms-specific questionnaire. RESULTS: Resting FEV1 values were above predicted values (114--121%) and not different between groups. Twenty-six percent of the study population demonstrated >10% postexercise drop in FEV1 and 29% reported two or more symptoms. However, the proportion of PFT-positive and PFT-normal athletes reporting two or more symptoms was not different (39% vs. 41%). Postrace cough was the most reported symptom, reported significantly more frequently for PFT-positive athletes (P < 0.05). Sensitivity/specificity analysis demonstrated a lack of effectiveness of self-reported symptoms to identify PFT-positive or exclude PFT-normal athletes. Postexercise lower limit reference ranges (MN-2SDs) were determined from normal athletes for FEV1, FEF25--75% and PEF to be -7%, -12.5%, and -18%, respectively. CONCLUSION: Although questionnaires provide reasonable estimates of EIA prevalence among elite cold-weather athletes, the use of self-reported symptoms for EIA diagnosis in this population will likely yield high frequencies of both false positive and false negative results. Diagnosis should include spirometry using an exercise/environment specific challenge in combination with the athlete's history of asthma symptoms.

Adolescent↗

PubMed2001

Hemoglobin/myoglobin oxygen desaturation during Alpine skiing.

PURPOSE: To investigate muscle blood volume (BV) change and hemoglobin/myoglobin oxygen desaturation (OD) during simulated giant slalom (GS) and slalom (SL) Alpine ski racing. METHODS: Joint angle, BV, OD, and heart rate (HR) were evaluated during GS and SL events in 30 junior elite skiers ages 9--17 yr (13.5 +/- 2.3). Subjects were stratified by ski class and age: group I, J1 and J2, ages 15--18 yr (16.8 +/- 0.8); group II, J3, 13--14 yr (13.6 +/- 0.7); and group III, J4 and J5, 9--12 yr (11.5 +/- 1.2). Near-infrared spectrophotometry (NIRS) was used to measure BV and OD in the capillary bed of the vastus lateralis during trials. Maximal OD was determined during thigh cuff ischemia (CI). Quadriceps cross-sectional area (CSA) was estimated by skin-fold and thigh circumference. RESULTS: Joint angles were smaller (P < 0.05) during GS than SL for ankle (83.8 +/- 11.9 degrees; 98.6 +/- 15.7 degrees ), knee (107.4 +/- 14.9 degrees; 118.3 +/- 18.0 degrees ), and hip (98.8 +/- 14.3 degrees; 107.5 +/- 16.2 degrees ). BV reduction from rest to peak exercise (Delta BV) was 30% greater (P < 0.05) during the GS than SL, whereas Delta OD was 33% greater (P < 0.05) during GS. Delta OD, relative to CI OD, was greater for all subjects during GS (79.2 +/- 3.7%) than SL (65.7 +/- 4.4%). This pattern continued within groups; group II displayed the greatest relative desaturation (82.9 +/- 7.6%). CSA was larger in older skiers (92.5 +/- 21.6; 72.5 +/- 12.3; 65.3 +/- 21.2 cm(2)) and correlated with Delta OD (P < 0.05). CONCLUSION: The larger reduction in BV (Delta BV change) and greater OD when skiers assumed lower posture during GS than SL may be related to greater effective static load secondary to higher percent of maximal voluntary contraction and is consistent with compromised blood flow to working muscle.

Adolescent↗

PubMed2000

Exercise-induced asthma screening of elite athletes: field versus laboratory exercise challenge.

PURPOSE: The purpose of this study was to compare a laboratory based exercise challenge (LBC) to a field based exercise challenge (FBC) for pulmonary function test (PFT) exercise-induced asthma (EIA) screening of elite athletes. METHODS: Twenty-three elite cold weather athletes (14 men, 9 women) PFT positive for EIA (FBC screened) served as subjects. Twenty-three gender and sport matched controls (nonasthmatics) were randomly selected to establish PFT reference values for normal elite athletes. Before FBC, athletes completed a medical history questionnaire for EIA symptoms. FBC evaluations consisted of baseline spirometry, actual or simulated competition, and 5, 10, and 15 min postexercise spirometry. PFT positive athletes were evaluated in the laboratory using an exercise challenge simulating race intensity (ambient conditions: 21 degrees C, 60% relative humidity). PFT procedures were identical to FBC. RESULTS: 91% of PFT positive and 48% of PFT normal athletes reported at least one symptom of EIA, with postrace cough most frequent. Baseline spirometry was the same for PFT positives and normal controls. Lower limit reference range (MN - 2 SD) of FEV1 for controls suggests that postexercise decrements of greater than approximately -7% indicate abnormal airway response in this population. Exercise time duration did not effect bronchial reactivity; 78% of FBC PFT positives were PFT normal post-LBC. CONCLUSION: Self-reported symptoms by elite athletes are not reliable in identifying EIA. Reference range criterion for FEV1 decrement in the elite athlete postexercise contrasts current recommended guidelines. Moreover, a large number of false negatives may occur in this population if EIA screening is performed with inadequate exercise and environmental stress.

Adolescent↗

PubMed2000

Incidence of exercise-induced bronchospasm in Olympic winter sport athletes.

PURPOSE: The purpose of this project was to determine the incidence of exercise-induced bronchospasm (EIB) among U.S. Olympic winter sport athletes. METHODS: Subjects included female and male members of the 1998 U.S. Winter Olympic Team from the following sports: biathlon, cross-country ski, figure skating, ice hockey, Nordic combined, long-track speedskating, and short-track speedskating. Assessment of EIB was conducted in conjunction with an "actual competition" (Olympic Trials, World Team Trials, World Cup Event, U.S. National Championships) or a "simulated competition" (time trial, game), which served as the exercise challenge. Standard spirometry tests were performed preexercise and at 5, 10, and 15 min postexercise. An athlete was considered EIB-positive based on a postexercise decrement in FEV1 > or = 10%. RESULTS: For the seven sports evaluated on the 1998 U.S. Winter Olympic Team, the overall incidence of EIB across all sports and genders was 23%. The highest incidence of EIB was found in cross-country skiers, where 50% of the athletes (female = 57%; male = 43%) were diagnosed with EIB. Across the seven sports evaluated, the prevalence of EIB among the female and male athletes was 26% and 18%, respectively. Among those individuals found to be EIB-positive were athletes who won a team gold medal, one individual silver medal, and one individual bronze medal at the Nagano Winter Olympics. CONCLUSIONS: These data suggest that: 1) EIB is prevalent in several Olympic winter sports and affects nearly one of every four elite winter sport athletes; 2) the winter sport with the highest incidence of EIB is cross-country skiing; 3) in general, EIB is more prevalent in female versus male elite winter sport athletes; and 4) athletes may compete successfully at the international level despite having EIB.

Asthma, Exercise-Induced↗

PubMed1998

Effect of music on perceived exertion, plasma lactate, norepinephrine and cardiovascular hemodynamics during treadmill running.

We examined the effects of listening to headphone music in ten well trained men (25.1 +/- 6 years) during treadmill running. Maximal oxygen consumption, determined by open circuit spirometry, was followed by two submaximal work bouts 72 hours apart. The work bouts consisted of a supine rest, a 15 minute run at 70% of maximal oxygen consumption, and a three minute active recovery period. Participants listened to music during one of the two trials. Hemodynamic variables and perceived exertion were recorded at three minute intervals during each trial. A venous blood sample, obtained prior to and following each trial, was assayed for norepinephrine and plasma lactate. Analysis of variance revealed significant differences (p < 0.05) between the no music versus the exercise with music trial for (aggregate data 3,6,9,12,15 minutes): heart rate 152.9 +/- 5.3 to 145.9 +/- 4.7 beats x min(-1); systolic blood pressure, 158.1 +/- 3.7 to 151.7 +/- 3.3 mmHg; rate-pressure product 242.2 +/- 11.5 to 222.1 +/- 11.4; exercise lactate 2.75 +/- 0.15 to 2.13 +/- 0.18 mmol x l(-1); and perceived exertion 14.4 +/- 0.4 to 12.9 +/- 0.4. A 17.5% lower level of norepinephrine (841.5 +/- 314.7 to 694.1 +/- 254.5 pg x ml[-1]) in the exercise and music trial was not statistically significant (p<0.05); however a moderate effect size (ES = 0.52) was calculated and may be of practical significance considering the variability of the sample. Higher values for hemodynamics and lactate in the no music trial is suggestive of a greater metabolic demand; however, oxygen consumption was not different. Perhaps the music allowed individuals to relax reducing muscle tension thereby increasing blood flow and lactate clearance while decreasing lactate production in working muscle. The combined results of this study suggest the introduction of music has a psychobiological impact on the exerciser demonstrated by changes in perceived effort, lactate and norepinephrine.

Adult↗

PubMed1998

Energy cost of rifle carriage in biathlon skiing.

PURPOSE: Since biathlon racing involves cross-country skiing while carrying a minimum weight 3.5-kg rifle, energy cost for rifle carriage could be significant to race outcome. The purposes of this study were to: 1) compare physiological measurements of biathletes roller skiing with and without rifle carriage, 2) compare energy cost of rifle carriage between women and men, 3) examine the relationship of cycle length and cycle rate to energy cost of rifle carriage, and 4) compare physiological measurements to calculated estimates of power requirements of rifle carriage. METHODS: We examined metabolic cost of rifle carriage during inclined roller ski-skating. National Team Biathletes (7 W, 8 M) performed treadmill roller ski-skating (2.46, 2.68, and 2.91 m.s-1, 8% incline, 5-min stages) with and without a 3.65 kg rifle. RESULTS: For W, HR, VO2, and VE during carriage were higher at all speeds, LA was higher at the fastest speed (P < 0.05). For M, VO2 and VE were higher at all speeds, HR and LA were higher at 2.68 and 2.91 m.s-1 (P < 0.05). Rifle mass as percent of body mass was different between W and M (6.6 +/- 0.7% vs 5.0 +/- 0.3%, P < 0.05). Percent increase in VO2 (2.1% and 1.3% per kg load; for W and M, respectively) was not different than rifle mass as percent body wt. Cycle length was related to increased VO2 and LA during rifle carriage for W (r = -0.59 and -0.70 to -0.85), and to LA for M (r = -0.66 to -0.83). CONCLUSION: The large range in cost between individuals (0.2 +/- 0.08 and 0.19 +/- 0.17 L.min-1; for W & M, respectively) suggests that individual economies for load carriage can be improved.

Adolescent↗

PubMed1998

Exercise tolerance, body composition and blood lipids in obese African-American women following short-term training.

BACKGROUND: The purpose of this investigation was to examine the exercise tolerance, body composition and blood lipids in African-American women, possessing greater than or equal to 30% body fat, following six weeks of endurance training. METHODS: Oxygen consumption (VO2), central hemodynamics, blood lipids, body weight, body fat, and the body mass index of seven subjects (21.0 +/- 0.8 yrs) were studied. Heart rate (HR), blood pressure (BP), exercise duration, rating of perceived exertion (RPE), blood lactate (bLA) and VO2 were obtained in response to a maximal exercise tolerance test on a motorized treadmill. Subjects trained three times per week for 50 minutes per session (30 minutes at 70% maximal oxygen consumption (VO2max). RESULTS: Dependent "t"-tests revealed significant (p < 0.05) increases in VO2max, 27%; exercise duration, 31%; as well as peak HR, systolic blood pressure (SBP), and bLA. Values for submaximal HR, SBP, RPE during the post-training test were lower. In addition, body weight, body fat and the body mass index decreased 2.2%, 1.3% and 3.4% respectively. There were no changes in blood lipids. CONCLUSIONS: These findings suggest short-term training at 70% VO2max provides the necessary stimulus for obese women to improve exercise tolerance and body composition. However, the training stimulus is insufficient to alter lipid profiles.

Adult↗

PubMed1994

Response of patients with coronary artery disease stratified by ejection fraction following short-term training.

The purpose of this study was to investigate the response of patients with ischemic heart disease and varied left ventricular function following 6 weeks of exercise training. We studied the oxygen consumption (VO2), and central hemodynamic and metabolic responses of 14 patients with coronary artery disease (CAD) stratified by left ventricular ejection fraction (EF). There were two groups of patients: normal EF (NEF), EF = 64 +/- 9.9 (mean +/- S.E.M.); n = 7, and diminished EF (DEF), EF = 36 +/- 11.6; n = 7. The patients ranged in age from 42 to 72 years (54.9 +/- 2.2), and were evaluated prior to and then following training. Measures of VO2, cardiac output (Qt) stroke volume (SV), heart rate (HR), exercise duration (XTIME) and intensity (XI), as well as plasma lactate (LA), and the catecholamines epinephrine (E) and norepinephrine (NE) were obtained in response to maximal cycle ergometry. Subjects trained three times per week, 30 min per session, at an intensity equal to 70% of their peak oxygen consumption. Repeated measures analysis of variance (ANOVA) revealed no interaction between groups suggesting a similar training response. Significant post-training changes (P < 0.05) were observed in peak VO2 (VO2peak) NEF, 11.8% increase, (16.0 +/- 1.3 to 17.9 +/- 1.1 ml/kg/min) and DEF, 9.3% increase (15.1 +/- 1.6 to 16.5 +/- 1.2 ml/kg/min); submaximal HR, 4% decrease in the NEF (95.57 +/- 4.58 to 92 +/- 4.43 beats/min) and a 6% decrease in the DEF (107.29 +/- 7.44 to 101.43 +/- 6.77 beats/min); XTIME NEF, 11.2% increase (7.8 +/- 0.57 to 8.67 +/- 0.61 min) and DEF, 16.6% increase (7.3 +/- 0.91 to 8.51 +/- 0.69 min); and XI NEF, 19.2% increase (104.3 +/- 11.3 to 124.3 +/- 12.9 W) DEF, 21.2% increase (94.3 +/- 18.5 to 114.3 +/- 16.9 W), and a 15% decrease in resting NE (350 +/- 26 to 296.9 +/- 19 pg/ml). There were no changes in Qt, SV, LA, E, peak NE or peak HR for either group. These findings suggest short-term endurance training at 70% VO2peak provide the necessary stimulus for individuals with CAD and NEF or DEF to display an improvement in XI, XTIME, and VO2peak. The lack of a significant enhancement in Qt with short-term training may indicate that the mechanism by which both study groups were able to attain significantly higher levels of VO2peak may have been attributable to peripheral mechanisms rather than any alterations in Qt, a central mechanism.

Coronary Disease↗

PubMed1994

Carbohydrate drinks and cycling performance.

We compared the effects of similarly tasting orange flavored drinks containing 0% (P), 6.4% (E1), and 10% (E2) carbohydrate (CHO) using 12 well-trained cyclists (VO2max = 5.0 l/min-1) on metabolic responses to exercise (EX) and a sprint type performance ride (PR). Each subject completed 3 separate 2 h EX bouts at 65% VO2max followed by a PR identified as the time in sec to complete 500 revolutions at a constant belt resistance of 29.4 N (ANOVA*). The CHO feedings or placebo of 3 ml/kg body weight were given double blind and counter-balanced at 0 min and every 20 min thereafter during EX. Blood samples were drawn and core temperature (Tr) was recorded at 0, 30, 60, 90, and 120 min of EX and 1 min post PR. Blood samples were analyzed for glucose (G) and lactate [LA-]. Blood G at 0 min were similar; however, at 120 min, G was 3.96 mM for P*, 4.57 mM for E1, and 4.77 mM for E2. Blood [LA-] remained similar throughout EX averaging (P, 2.6 mM; E1, 2.9 mM; E2, 2.5 mM). Tr at 120 min was also similar (P, 38.5 degrees C; E1, 38.6 degrees C; E2, 38.3 degrees C). Mean PR times for P(264.4 s)**, E1 (255.3 s)*, E2 (252.4 s)* indicate consumption of a CHO drink during EX improves PR. Furthermore, a 10% CHO drink improves PR more than a 6.4% CHO drink.

Adolescent↗

PubMed1993

Interrelationship between plasma potassium concentration, pulmonary ventilation and electrocardiographic change during and after highly intense exercise.

OBJECTIVE: The purpose of this investigation was to induce elevated plasma concentrations of potassium (K+) efflux from active muscle cells during intense muscular exercise. The relationship between K+, pulmonary ventilation (VE) and EKG changes, specifically T-wave amplitude, is presently controversial. DESIGN: Repeated measures design. SETTING: Human performance laboratory. PARTICIPANTS: Twelve volunteer trained recreational cyclists (10 males, mean age 31.9 +/- 7.4, and 2 females, mean age 27.5 +/- 0.7, mean VO2max 571.2 +/- 6.4 ml.kg.min-1). OUTCOME MEASURE: Subjects performed 10 min of pedaling at 90 rpm, yielding a power output of 45 W.min-1 on a mechanically braked cycle ergometer as a warm-up. Each exercise stage was 2 min in duration, beginning at 135 W and increased by 45 W thereafter until voluntary exhaustion. Respiratory gas exchange measures were obtained every 10 sec. Venous blood samples for K+ and lactate (LA-) determination were drawn at rest, at the end of stage 2, all subsequent stages, and during 3 and 10 min of recovery. EKG recordings were concurrent with venous sampling. RESULTS: Statistical analyses for VE vs. K+, respiratory exchange ratio (RER) vs. K+ and RER vs. LA- revealed neither significant change nor an associative relationship from stages 1-3. However, stages 4-8 were statistically significant (p < .05) and highly correlated. No relationship was found between K+ change and T-wave amplitude during exercise or recovery. CONCLUSION: These data indicate a strong relationship between selected respiratory gas exchange measures and K+ during intermediate to highly intense exercise.

Adult↗

PubMed1988

Long-term survival of patients with low ejection fraction: surgical versus medical management.

From May 1974 to December 1982, 3,592 patients underwent cardiac catheterization at the Buffalo Veterans' Administration Medical Center. Three hundred sixty-three patients (10.2%) presented with ejection fractions (EFs) < 40%. Of these, 194 had significant coronary artery disease. Follow-up data for retrospective analysis of survival rates were available for 173 of the 194 patients. Fifty-eight of these 173 had undergone coronary artery bypass surgery, while the remaining 115 had received medical treatment. The cumulative survival rates at 8 years for patients with EFs < 25% reveal a significantly better survival rate (61% vs. 29%, p <.03) for surgically treated patients. We conclude that coronary artery bypass surgery yields higher 8-year survival rates than does medical treatment for patients with compromised left ventricular function and significantly low EFs (< 25%).

Journal Article↗

PubMed1986

Stress test evaluation of patients with poor left ventricular function before and after coronary artery bypass surgery.

Between May 1976 and December 1982 (104 months), 152 patients from a total of 3592 patients who had coronary angiography at the Buffalo Veterans Administration Medical Center had coronary artery disease with left ventricular ejection fractions of 40% or below. Sixty-three patients in this group had coronary bypass surgery. Thirty patients who had graded exercise tests done before and after surgery improved in their peak exercise double product and systolic blood pressure (p value <.05) accompanied by increased work capacity (p value < 0.02). Nineteen patients who had identical exercise protocols also showed increases in exercise time (p value <.05). We believe that coronary artery bypass surgery improves exercise capacity in selected patients with compromised left ventricular function.

Journal Article↗