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PubMed2006

Circulating levels of soluble CD26 are associated with phobic anxiety in women.

Dipeptidyl peptidase IV (DPPIV or CD26) is an ubiquitously expressed protease that could play a role in the pathogenesis of anxiety in view of its capacity to cleave several behaviourally active neuropeptides. Hereto we sought to determine the relationship between phobic anxiety, as measured by the Crown-Crisp index, and circulating levels of soluble CD26 (sCD26) in a large cohort of 1017 Italian women participating in a general health survey. The association between sCD26 levels and phobic anxiety was tested using simple correlation analysis, linear regression and multivariate logistic regression analysis. A highly significant inverse association was found between sCD26 concentrations and anxiety scores both in simple correlation and linear regression analysis. Compared with subjects in the first tertile of sCD26 levels, the age-adjusted odds ratio for scoring >/=6 compared to scoring 0 or 1 was 0.31 (95% CI: 0.18-0.74) for the second and 0.47 (95% CI: 0.34-0.63) for the third tertile. Altogether, our data suggest that reduced plasma sCD26 concentrations could be a marker of high levels of phobic anxiety in women.

Adult↗
PubMed2000

Addition of supplementary foods and infant growth (2 to 24 months).

OBJECTIVE: To determine the effect of adding supplementary foods on infant growth 2 to 8 and 12 to 24 months. METHODS: Length (cm/month) and weight (kg/month) of white infants (n = 94) were measured five to nine times from 2 to 24 months of age. Mothers reported birth weights, infants' ages at first introduction of supplementary food, illnesses and information sources about infant feeding. Simple linear regression equations were used to compute slopes for each child (unit changes in length and in weight by age). Stepwise linear regression was used to determine the effect on weight and length slopes by the introduction of supplementary foods (e.g., an infant's age when cereal, fruit, juice, vegetables and a meat cluster were first added) to the diet. Breast feeding (months duration or ever fed), illness scores and gender were covariates in the regression models. RESULTS: A significant model (F = 10.09, p = .002) for weight gain (2 to 8 months) showed that gender explained 10% of the variance; for length slope, the model was non-significant and gender explained 3% of the variance. Females had a slower weight gain compared to that of males. None of the covariates or supplementary foods were retained in the models. Weight prior to 12 months was the best predictor (p = .0001, 54% of the variance) of weight gain 12 to 24 months. CONCLUSIONS: Unit changes in weight or length for an infant's age were not statistically associated with the timing of when supplementary foods were first added to the diet 2 to 8 or 12 to 24 months. Weight prior to 12 months was a significant predictor of weight gain 12 to 24 months.

Body Height↗
PubMed1994

Evaluation of a new slide-based laser scanning cytometer for DNA analysis of tumors. Comparison with flow cytometry and image analysis.

DNA measurements generated by a new automated slide-based cytometer, the laser scanning cytometer (LSC), were compared with those produced by commercial flow cytometry (FCM) and image analysis (IA) devices. Laser scanning-cytometric analysis was performed by scanning alcohol-fixed, propidium iodide-stained tumor imprints with a 5-microns spot laser beam. Fifty-three malignant tumors (51 breast carcinomas and 2 lung carcinomas) were studied. Ploidy concordance rates for FCM versus LSC, IA versus LSC, and FCM versus IA were 96%, 91%, and 91%, respectively. Statistically significant agreement between methods was determined by linear regression analysis of DNA indices. Synthesis-phase fractions generated by FCM and LSC also were comparable, as demonstrated by linear regression (r = .83). Mean coefficients of variation for the LSC compared favorably with those for FCM and IA. The few discrepancies in ploidy status between methods could be explained by sampling error, the presence of possible near-diploid aneuploid populations that could not be effectively resolved by one or another modality, and the visual selection bias with IA when small aneuploid cell populations were present. The LSC shares many useful features with FCM, including automation, accuracy of quantitation, rapidity, and generation of reliable information regarding cell proliferation (synthesis-phase fraction). In addition, it has some of the advantages of IA, such as minimal tissue requirement, no need for special preparation, and the potential for visual selection of the cells measured. The LSC holds great promise for use in the clinical laboratory because of these combined characteristics.

Breast Neoplasms↗
PubMed1996

Dose-response characteristics of spinal bupivacaine in volunteers. Clinical implications for ambulatory anesthesia.

BACKGROUND: Small doses of bupivacaine may be a reasonable choice for spinal anesthesia for patients having ambulatory surgery. However, few dose-response data are available to guide the selection of reasonable doses of bupivacaine for different ambulatory procedures. METHODS: Eight volunteers per group were randomized to receive 3.75, 7.5, or 11.25 mg of 0.75% bupivacaine with 8.25% dextrose in a double-blind manner. Sensory block was assessed with pinprick, transcutaneous electrical stimulation equivalent to surgical incision at the ankle, knee, pubis, and umbilicus, and with duration of tolerance to pneumatic thigh tourniquet. Motor block at the quadriceps and gastrocnemius muscles was assessed with isometric force dynamometry. Times until recovery from spinal anesthesia were recorded. Dose-response relationships were determined by linear regressions. Mean (95% confidence intervals) for durations of sensory and motor block per milligram of bupivacaine administered were calculated from linear regressions. RESULTS: Significant dose-response relationships (P < 0.006) were determined for sensory block, motor block, and time until recovery (R from 0.6 to 0.9). Within the range of doses studied, each additional milligram of bupivacaine was associated with an increase in duration of tolerance to transcutaneous electrical stimulation of 10 (7 to 13) min, an increase in tolerance to tourniquet of 7 (2 to 11) min, an increase in duration of motor block of 8 (5 to 12) min, and an increase in time until recovery of 21 (17 to 25) min. CONCLUSIONS: These dose-response data may guide the selection of reasonable doses of bupivacaine for various outpatient procedures, although individual responses vary.

Adult↗
PubMed1998

Quantitative evaluation of the optic nerve head in early glaucoma.

AIMS: Progressive loss of neuroretinal rim tissue is known to occur early in glaucoma and measurement of the neuroretinal rim area is possible by magnification corrected analysis of optic disc photographs (planimetry). This study was performed to determine whether the facility to distinguish between glaucomatous and normal optic discs could be improved upon by: (a) taking into account the known relation between optic disc size and neuroretinal rim area, and (b) measuring rim area in a number of segments, in order to detect focal changes. METHODS: Planimetric examination of the optic disc photographs of 88 control subjects and 51 patients with early visual field defects was performed. In the control group, multiple linear regression analysis was performed between neuroretinal rim area and optic disc area, age, sex, eye side, refraction, and keratometry. This was repeated for the whole disc and for each of twelve 30 degree segments. Normal ranges were defined by the 98% prediction intervals of the regression analysis and the sensitivity and specificity for correct identification of optic discs in the two groups determined. RESULTS: Multiple linear regression demonstrated significant associations between the neuroretinal rim area and optic disc area and age in normal subjects. Sensitivity and specificity for glaucoma diagnosis, using the cut off derived from the 98% prediction intervals, was 37.7% and 98.9% respectively when total neuroretinal rim area alone was considered, and 88.7% and 94.3% respectively when the 30 degree segments were included. The most frequent pattern of neuroretinal rim loss was diffuse, followed by thinning in more than one sector and then by thinning in the inferotemporal sector alone. CONCLUSIONS: This method of optic disc analysis enables the examiner to identify glaucomatous optic discs at the stage of early perimetric loss with a high degree of precision. Optic disc photography is simple, and fundus cameras are widely available. This method for glaucoma case identification may therefore be suitable for the primary care setting as well as hospital practice.

Adult↗
PubMedDate not supplied

Intima-media thickness and arterial distensibility in Behçet's disease.

The etiology of Behçet's disease, a systemic vasculitis, is unknown. Vascular involvement may be seen in 25% of patients with Behçet's disease. Vasculitis make the prognosis of Behçet's disease severe. The aim of this study is to examine the structural and functional changes and relations of these changes with progression and prognosis of Behçet's disease. For this purpose, 40 patients with Behçet's disease and 40 healthy volunteer control subjects were analyzed, additionally patients with Behçet's disease were divided into 2 subgroups as those with vascular complications and those without vascular complications. Intima-media thickness and arterial distensibility were measured in all subjects with carotid artery ultrasonography. Carotid artery distensibility was significantly lower in the patient group compared to the control group (0.67 +/- 0.2, 0.93 +/- 0.4, p < 0.05), and carotid artery IMT was significantly higher (0.59 +/- 12, 0.80 +/- 0.11, p < 0.05). A statistically significant increase in IMT has been detected (0.77 +/- 11, 0.86 +/- 11, p < 0.05) in patients with Behçet's disease with vascular involvement compared to patients with Behçet's disease without vascular involvement, arterial distensibility in patients with vascular disease was similar with those who has no vascular disease (0.69 +/- 0.25, 0.63 +/- 0.25, p > 0.05). There was a significant negative linear regression between arterial distensibility and systolic blood pressure (SBP) (B = -1 x 10(-2), p < 0.05), and a significant positive linear regression has also been found between IMT and SBP and diastolic blood pressure (DBP) and pulse pressure (PP) (B = 6.8 x 10(-3) for SBP, p < 0.05, B = 6.9 x 10(-3) for DBP, p < 0.05, B = 6 x 10(-3) for PP, p < 0.05). As a result, IMT increases and AD decreases in patients with Behçet's disease compared to results in the control group. Although more studies are required for this subject, use of noninvasive parameters such as IMT and AD, which reflect the structural and functional characteristics of vasculature, may be useful to define disease progression and subjects at high risk.

Adult↗
PubMed1992

A comparison method for mean frequency estimators for Doppler ultrasound.

Mean frequency estimators as used in pulsed Doppler ultrasound equipment should provide an accurate (quality) and consistent (robustness) estimate over a wide range of signal conditions. In a simplified signal model, the main parameters to consider are the noise level, mean frequency, bandwidth and power of both the Doppler signal and the stationary component over a given time window. It may be expected that one estimator for a given parameter combination exhibits a good performance while another estimator for the same parameter combination behaves poorly. To allow direct comparison between different types of frequency estimators, a method is introduced to evaluate the quality and robustness of estimators for a common signal space covering a wide range of realistic parameter combinations. The method is illustrated using three different mean frequency estimators: (1) a first order autoregressive estimator in combination with a stationary echo filter; (2) a second order autoregressive estimator; and (3) a complex linear regression estimator in combination with a stationary echo filter. It is concluded that, for the parameter combination considered, the complex linear regression estimator exhibits the best quality (low variance and bias of the estimate) and robustness (consistent quality for all parameter combinations).

Artifacts↗
PubMedDate not supplied

[Polyalveolosis: pathogenesis of congenital lobar emphysema?].

BACKGROUND: Congenital lobar emphysema is an unusual condition and its pathogenesis remains unknown. The variety of findings in pathology studies of the resected specimens led to increasing academic interest. About 50 per cent of the cases have no definitive diagnosis in pathology. The most recent theory proposes an increased number of alveoli within each acinus (polyalveolar lobe). PURPOSE: The aim of this paper is to report the morphometric measures of surgical specimens of 12 patients with congenital lobar emphysema, using the Emery and Mithal technique (radial alveolar count). METHODS: We made a case-control study, classifying the cases by age. Mann-Whitney's U test and linear regression techniques were used in data analysis: Mann-Whitney's U in comparing the cases and respective controls and linear regression to evaluate the influence of age in the measures found. RESULTS: The results revealed a significantly higher radial alveolar count than expected for the age group under 3 years; no difference was observed in the age group between 3 and 7 years and in children older than 7, the radial alveolar count was lower than expected. The normal development of the lung consists in an increasing number of alveoli increase from birth until adulthood, but this number remains constant, independent of age in congenital lobar emphysema. CONCLUSIONS: Such findings allow us to conclude that polyalveolar lobe can and must be diagnosed by a simple and practical method, such as the radial alveolar count, which decreases the incidence of the unknown etiology. The findings of an increased number of alveoli on patients younger than 3 is related to congenital lobar emphysema, since the number of alveoli does not increase in congenital lobar emphysema, just the opposite to what one would expect in the normal development of the lung.

Adolescent↗
PubMed1996

Studies on acid oils and fatty acids for chickens. I. Influence of age, rate of inclusion and degree of saturation on fat digestibility and metabolisable energy of acid oils.

1. Using a multi-rate assay, 3 commercial acid oils (sunflower, soyabean and tallow) were evaluated for AMEn and added fat digestibility with broiler chicks, at 11, 25, 39, 53 and 60 d of age. The regression equations of AMEn values or ME of available fat on rate of inclusion of fat were calculated. 2. Significance was achieved for linear regression but not for quadratic regression in both variables; neither rate of inclusion nor age of birds (except for tallow acid oil at 25 d) significantly affected the AMEn or ME of fat. Metabolisable energy of fat (on a dry matter basis) calculated from combined linear regression equations was 19.14MJ/kg for sunflower acid oil, 18.09MJ/kg for tallow acid oil and 27.94MJ/kg for soyabean acid oil. Differences between sunflower and soyabean acid oils were attributed in variations in unsaponifiable and non-eluted materials of both fats. 3. Abdominal fat pad weight and its relationship to carcase weight were also studied with birds slaughtered at 67 d of age. Chicks given tallow acid oil deposited larger amounts of abdominal fat, and this deposition was directly related to the rate of inclusion of acid oil in the diet.

Abdomen↗
PubMed1997

Predictive patterns of suicidal behavior: the United States armed services versus the civilian population.

Suicide is the eighth leading cause of death in the United States and the third leading cause of death in the military population. The purpose of this study was to compare the suicide rates of the Army, Navy, Marine Corps, and Air Force to the U.S. population for the years 1980 through 1992. Multivariate linear regression analytic techniques were used to test the specific effects of year, service membership, and gender on suicide rates. A hierarchical linear regression equation resulted in R2 = 0.6737, a highly predictive finding (F112,18 = 13.600, p < 0.000). Further controlled hypothesis testing suggested that each independent variable provided a unique contribution to the total variance accounted for in suicide rates. A follow-on set of time series regressions was used to assess the effects of gender and specific military service on suicide rates over the 13-year period. Findings revealed that suicide rates for civilian males are increasing, whereas civilian female rates are declining. No significant trends by year were shown among the services. Military suicide rates were consistently lower than civilian rates, and military female rates tended to be lower yet than military male rates.

Feasibility Studies↗
PubMedDate not supplied

Angina and socio-economic status in Ontario: how do characteristics of the county you live in influence your chance of developing heart disease?

OBJECTIVE: To assist in the development of community heart health programming and policy development, the Central West Health Planning Information Network (CWHPIN) was asked by its partners to collaborate in obtaining information that might clarify the relationships between socio-economic status (SES) and heart disease among residents of Ontario, Canada. The purpose of this component of the project was to explore, at the county level, how much of the variation in angina pectoris (angina) could be explained by SES variables. STUDY DESIGN: Linear regression modeling was used to identify key predictors of angina hospitalization rates in counties Ontario-wide. RESULTS: Results of the linear regression modeling showed that SES variables (most notably education and occupation) were key predictors of angina, even when traditional risk factors (i.e., smoking, etc.) were included in the analysis. CONCLUSION: This study demonstrates that, at the county level, socio-economic variables such as education and occupation have a significant relationship with rates of heart disease at the population level, even when including the traditional risk factors in the analysis.

Adult↗
PubMed2005

Identification of a food pattern characterized by high-fiber and low-fat food choices associated with low prospective weight change in the EPIC-Potsdam cohort.

The aim of the study was to identify a dietary pattern predictive of subsequent annual weight change by using dietary composition information. Study subjects were 24,958 middle-aged men and women of the European Prospective Investigation into Cancer and Nutrition-Potsdam cohort. To derive dietary patterns, we used the reduced rank regression method with 3 response variables presumed to affect weight change: fat density, carbohydrate density, and fiber density. Annual weight change was computed by fitting a linear regression line to each person's body weight data (baseline, and 2- and 4-y follow-up) and determining the slope. In linear regression models, the pattern score was related to annual weight change. We identified a food pattern of high consumption of whole-grain bread, fruits, fruit juices, grain flakes/cereals, and raw vegetables, and of low consumption of processed meat, butter, high-fat cheese, margarine, and meat to be predictive of subsequent weight change. Mean annual weight gain gradually decreased with increasing pattern score (P for trend < 0.0001), i.e., subjects scoring high for the pattern maintained their weight or gained significantly less weight over time compared with subjects with an opposite pattern. However, the prediction of annual weight change by the food pattern was significant only in nonobese subjects. In this study population, we identified a food pattern characterized by high-fiber and low-fat food choices that can help to maintain body weight or at least prevent excess body weight gain.

Body Weight↗
PubMed2004

How much tachycardia in infants can be attributed to fever?

STUDY OBJECTIVES: We evaluate the hypothesis that pulse rate increases linearly with increased body temperature in infants and determine how much tachycardia in infants can be explained by a 1 degrees C (1.8 degrees F) increase in body temperature. METHODS: Infants younger than 1 year and presenting to a pediatric emergency department were prospectively enrolled. Rectal temperature and pulse rate were measured. Research personnel rated behavioral state as sleeping, awake and quiet, fussy, or crying. Patients were excluded if they were fussy or crying or if they had any medical condition expected to cause tachycardia. The remaining patients were divided into 6 age-based groups. Linear regression analysis of pulse rate and temperature was performed for each group. RESULTS: Four hundred ninety patients were enrolled. Pulse rate increased linearly with temperature in all age groups older than 2 months (adjusted r2=0.102 to 0.376) but not in infants younger than 2 months (adjusted r2=0.004). In infants aged 2 months or older, a multivariate linear regression model adjusted for age showed that pulse rate increased an average of 9.6 beats/min (95% confidence interval 7.7 to 11.5) per 1 degrees C (1.8 degrees F) increase in temperature (adjusted r2=0.225). At any given temperature, the prediction interval for an individual's pulse rate had a span of approximately 64 beats/min. CONCLUSION: In infants 2 to 12 months of age, pulse rate increases linearly with body temperature, with a mean increase of 9.6 beats/min for each 1 degrees C (1.8 degrees F) increase in body temperature. Pulse rates of individual infants vary greatly, however, with a broad range of pulse rates observed at any given temperature.

Body Temperature↗
PubMed2005

Vitamin D and calcium intakes from food or supplements and mammographic breast density.

BACKGROUND: A better understanding of factors that affect breast density, one of the strongest breast cancer risk indicators, may provide important clues about breast cancer etiology and prevention. This study evaluates the association of vitamin D and calcium, from food and/or supplements, to breast density in premenopausal and postmenopausal women separately. METHODS: A total of 777 premenopausal and 783 post-menopausal women recruited at two radiology clinics in Quebec City, Canada, in 2001 to 2002, completed a food frequency questionnaire to assess vitamin D and calcium. Breast density from screening mammograms was assessed using a computer-assisted method. Associations between vitamin D or calcium and breast density were evaluated using linear regression models. Adjusted means in breast density were assessed according to the combined daily intakes of the two nutrients using generalized linear models. RESULTS: In premenopausal women, total intakes of vitamin D and calcium were inversely related to breast density (beta = -1.4; P = 0.004 for vitamin D; beta = -0.8; P = 0.0004 for calcium). In multivariate linear regression, simultaneous increments in daily total intakes of 400 IU vitamin D and 1,000 mg calcium were associated with an 8.5% (95% confidence interval, 1.8-15.1) lower mean breast density. The negative association between dietary vitamin D intake and breast density tended to be stronger at higher levels of calcium intake and vice versa. Among postmenopausal women, intakes of vitamin D and calcium were not associated with breast density. CONCLUSION: These findings show that higher intakes of vitamin D and calcium from food and supplements are related to lower levels of breast density among premenopausal women. They suggest that increasing intakes of vitamin D and calcium may represent a safe and inexpensive strategy for breast cancer prevention.

Adult↗
PubMed1998

Do leptin levels predict weight gain?--A 5-year follow-up study in Mauritius. Mauritius Non-communicable Disease Study Group.

OBJECTIVE: To investigate whether relative baseline leptin levels predict long-term changes in adiposity and/or its distribution. RESEARCH METHODS AND PROCEDURES: In a longitudinal study of 2888 nondiabetic Mauritians aged 25 years to 74 years who participated in population-based surveys in 1987 and 1992, changes in body mass index (BMI), waist/hip ratio (WHR), and waist circumference were compared between "hyperleptinemic," "normoleptinemic," and "hypoleptinemic" groups. "Relative leptin levels" were calculated as standardized residuals from the regression of log10 leptin on baseline BMI to provide a leptin measure independent of BMI. Analyses were performed within each sex. A linear regression model was used to assess the effect of standardized residuals on changes in BMI, WHR, and waist circumference, independent of baseline BMI, age, fasting insulin, and ethnicity. RESULTS: After adjusting for age and baseline BMI by analysis of covariance, there was no difference in changes in BMI, WHR, or waist circumference between men with low, normal, or high relative leptin levels. Among women, there was a significant difference in deltaWHR across leptin groups, such that the largest increase occurred in the "normal" leptin group. For both men and women, the linear regression models explained approximately 10% of variation in dependent variables, and the only significant independent variables were age, BMI, and being of Chinese origin, compared with Indian origin. DISCUSSION: These findings do not support a role for leptin concentration in predicting weight gain or changes in fat distribution in adults over a 5-year period.

Blood Glucose↗
PubMed2006

Acute health effects of the Tasman Spirit oil spill on residents of Karachi, Pakistan.

BACKGROUND: On July 27 2003, a ship carrying crude oil ran aground near Karachi and after two weeks released 37,000 tons of its cargo into the sea. Oil on the coastal areas and fumes in air raised health concerns among people. We assessed the immediate health impact of oil spill from the tanker Tasman Spirit on residents of the affected coastline in Karachi, Pakistan. METHODS: We conducted a study consisting of an exposed group including adults living in houses on the affected shoreline and two control groups (A and B) who lived at the distance of 2 km and 20 km away from the sea, respectively. We selected households through systematic sampling and interviewed an adult male and female in each household about symptoms relating to eyes, respiratory tract, skin and nervous system, smoking, allergies, beliefs about the effect on their health and anxiety about the health effects. We used logistic regression procedures to model each symptom as an outcome and the exposure status as an independent variable while adjusting for confounders. We also used linear regression procedure to assess the relationship exposure status with symptoms score; calculated by summation of all symptoms. RESULTS: Overall 400 subjects were interviewed (exposed, n = 216; group A, n = 83; and group B, n = 101). The exposed group reported a higher occurrence of one or more symptoms compared to either of the control groups (exposed, 96% vs. group A, 70%, group B 85%; P < 0.001). Mean summary symptom scores were higher among the exposed group (14.5) than control group A (4.5) and control group B (3.8, P < 0.001). Logistic regression models indicated that there were statistically significant, moderate-to-strong associations (Prevalence ORs (POR) ranging from 2.3 to 37.0) between the exposed group and the symptoms. There was a trend of decreasing symptom-specific PORs with increase in distance from the spill site. Multiple linear regression model revealed strong relationship of exposure status with the symptoms score (beta = 8.24, 95% CI: 6.37-10.12). CONCLUSION: Results suggest that the occurrence of increased symptoms among the exposed group is more likely to be due to exposure to the crude oil spill.

Adolescent↗
PubMed1988

Evaluation of the Datascope ACCUSAT pulse oximeter in healthy adults.

Arterial hemoglobin oxygen saturation measured with the Datascope ACCUSAT pulse oximeter was compared with simultaneous arterial hemoglobin oxygen saturation measurements in healthy adult volunteers. One hundred thirty-five arterial blood samples ranging in saturation from 63 to 100% were obtained from 15 adults, aged 20 to 43 years. These subjects had different skin pigmentation, hematocrit, and smoking habits. Steady-state hypoxia was achieved by varying the inspired oxygen concentration between 10 and 21%. Readings from the Datascope ACCUSAT pulse oximeter and the Hewlett-Packard 47201A ear oximeter were compared with arterial blood samples analyzed by the Instrumentation Laboratories IL 282 in vitro CO-Oximeter. The equation for the best fitted linear regression line between the ACCUSAT pulse oximeter and the reference IL 282 CO-Oximeter was: ACCUSAT = 1.08(IL) - 6.86. The linear regression analysis revealed a high degree of correlation (r = 0.99), and a small standard error of the estimate (SEE = 1.29%). Simultaneous comparisons between arterial hemoglobin oxygen saturation measured with the ACCUSAT pulse oximeter and the Hewlett-Packard ear oximeter also showed a close correlation (r = 0.99, SEE = 1.47%). A similar comparison between the ACCUSAT and the Ohmeda 3700 pulse oximeter revealed good correlation (r = 0.99, SEE = 1.72%). We found that the ACCUSAT pulse oximeter is an accurate instrument for measuring arterial hemoglobin oxygen saturation noninvasively in the range between 60 and 100%.

Adult↗
PubMed2001

Oxygen uptake-heart rate relationship in élite wheelchair racers.

The American College of Sports Medicine (ACSM) recommends that, as a general rule for health purposes, individuals should exercise at 40%-85% of their maximal oxygen uptakes. Moreover, it has been suggested that 55%-90% of the maximal heart rate may be used as an alternative estimate of these percentage maximal oxygen uptake values. The present study examined the relationship between percentage peak heart rate (% HRpeak) and percentage peak oxygen uptake (% VO2peak) during steady-state incremental intensity wheelchair propulsion of 16 élite, male wheelchair racers (WR). Oxygen uptake was determined during each submaximal exercise stage and heart rate (HR) was continuously monitored. The VO2peak was subsequently determined using a separate protocol. Linear regression equations of % HRpeak versus % VO2peak for each participant included % HRpeak values corresponding to 40%, 60%, 80% and 85% VO2peak. The linear regression equation, derived as the group mean of the slope and intercept terms determined for each individual, was: % peak HR = 0.681 x % peak VO2 + 33.2. The group mean of the individual correlation coefficients for the VO2-HR relationship was 0.99. The values of % HRpeak for each of the % VO2peak values below 85% were significantly greater (P<0.01) than those suggested by the ACSM. This suggests that the ACSM guidelines below 85% VO2peak, based on % HRpeak, may underestimate the relative exercise intensity (i.e. % VO2peak) in the WR population. However, in élite level WR, % HRpeak can be recommended as an alternative estimate of % VO2peak at wheelchair propulsion intensities of 85% VO2peak or more.

Adult↗