Search PubMed⌕ Search

Biomedical subjects

A Chamoux

Publications and source records attributed to A Chamoux.

13 recordsLinked to original sources
PubMed2003

Elevated salivary cortisol levels as a result of sleep deprivation in a shift worker.

BACKGROUND: This paper reports a case from a group of 63 shift-workers for whom adaptation to shift-work was evaluated through measurement of salivary cortisol levels. METHODS: Workers' saliva was sampled and cortisol levels measured at intervals of 2 h during morning, evening and night shifts. RESULTS: For one subject among the 63, very high values of cortisol (an approximately 6-fold increase) were observed for the morning (M) shift, but with normal values found for evening (E) and night (N) shifts. Individual mean and peak cortisol values were 48.4 and 67.8 nmol/l against group mean and peak cortisol values of 8.9 and 11.0 nmol/l. Retrospective questioning showed that this subject was healthy and there were no indicators of long-term stress. CONCLUSION: This cortisol rise was deduced to be caused by sleep deprivation as a result of rapidly rotating shift patterns.

Adaptation, Physiological↗
PubMed2002

Median maximal heart rate for heart rate calibration in different conditions: laboratory, field and competition.

The objective of this study was to evaluate the variability of maximal heart rate in three different conditions: laboratory tests, field tests, and competitions. Sixteen male endurance volunteers were tested in five exhaustive tests for each condition. All exhaustive events were heart rate monitored (Accurex plus, Polar Electro, Finland) and true maximal heart rates were assessed and compared with each other and with predicted maximal heart rates. Results show that under the three conditions HR(peaks) were not statistically different (p = 0.62, NS, Friedman test). Mean HR(peaks) (SD) were: laboratory = 194.3 (7.8), field = 193.8 (11.8), competition = 192.3 (10.1) beats x min(-1). Conditions for reaching individual heart rate peak were in the laboratory (treadmill VO(2)max protocol) for 5 subjects, in field tests for 7 subjects and in competitions for 6 subjects (two circumstances for two subjects). A large intra-individual variation existed in the three circumstances (+/- 6 beats x min(-1)). Absolute median maximal heart rate was 190.0 bpm (9.32) i.e 7.6 bpm lower than heart rate peak. Both were highly related (rho = 0.89, z = 3.449, p = 0.0006, Spearman test). Median maximal heart rates inter-condition relationship were higher. Median maximal heart rate was more stable and took more information into account than an isolated peak. It gives a central value that minimizes the potential risk of under or over estimation when calibrating exercise intensities with HR.

Adult↗
PubMed2000

Heart rate monitors and abnormal heart rhythm detection.

We test the accuracy of two third generation heart rate monitors (HRM), Accurex Plus and Vantage NV and compare these data with those of an older monitor, PE 4000. Then we investigate responses of the HRM's to abnormal heart rhythms (HR). Accurex Plus and Vantage NV, and PE 4000 were tested in the laboratory under both stable and transient conditions. The Phantom 320 HR simulator gave 7 stable heart rates, each lasting 3 min. The responses of the HRM's to abnormal heart rhythms were tested with an automatic arrhythmia program lasting 17 min. The new HRM's, Accurex Plus and Vantage NV, were more accurate (89 to 94% and over 98% at +/-3 beats per min) in the stable state than the PE 4000. They all showed a smoothing effect in transient measurements, which was stronger in decelerating HR (1st case) than in accelerating HR (2nd case). - 1st case: Accurex Plus =Vantage NV >PE 4000 -2nd case: PE 4000 >Accurex =Vantage. Most isolated heart rhythm disorders (missing beat, pause < 4 s, SVEA, and SVT) were either not detected or rejected. Signal changes such as changes in QRS (ventricular bigeminy) may cause detection losses, and so modify calculated heart rate. HR signal rising/dropping slopes caused by sudden heart rhythm disorders, was notably attenuated, with a consequent loss of HR accuracy. Although the usefulness of HRM's in detecting HR disorders is limited, they have some value with serious disorders, like pause >4 s, important bradycardia or tachycardia.

Adult↗
PubMed2000

Components and variations in daily energy expenditure of athletic and non-athletic adolescents in free-living conditions.

The objectives of the study were to determine: (1) daily energy expenditure (EE) of athletic and non-athletic adolescents of both sexes in free-living conditions; (2) day-to-day variations in daily EE during 1 week; (3) energy costs of the main activities; and (4) the effect of usual activity on EE during sleep, seated and miscellaneous activities. Fifty adolescents (four groups of eleven to fifteen boys or girls aged 16-19 years) participated in the study. Body composition was measured by the skinfold-thickness method, and VO2max and external mechanical power (EMP) by a direct method (respiratory gas exchanges) on a cycloergometer. Daily EE and partial EE in free-living conditions were computed from heart-rate (HR) recordings during seven consecutive days using individual prediction equations established from the data obtained during a 24 h period spent in whole-body calorimeters with similar activities. Fat-free mass (FFM), VO2max, EMP, daily EE and EE during sleep were significantly higher in athletic than in non-athletic subjects. After adjustment for FFM, VO2max, EMP, daily EE and EE during exercise were still higher in athletic than in non-athletic adolescents (P < 0.001). However, adjusted sleeping EE was not significantly different between athletic and non-athletic adolescents. Increases in exercise EE were partly compensated for by significant reductions in EE during schoolwork and miscellaneous activities. Thus, the differences in daily EE between athletic and non-athletic subjects resulted mainly from increases in FFM and EE during exercise (duration and energy cost).

Adolescent↗
PubMed1999

[Chemical odor intolerance. 5 cases].

BACKGROUND: Chemical odor intolerance is a benign, non-specific, generally subjective syndrome triggered by inhalation of non-toxic doses of chemical compounds or products which had been previously well tolerated. We report five characteristic cases and discuss current data. CASE REPORTS: Five patients (3 women, 2 men; age range 23-52 years) presented the basic criteria of chemical odor intolerance: acquired syndrome, non-specific signs (headache, nausea, vertigo ...) triggered by the odor of one or more chemical substances. Physical examination and exploratory tests were normal. In 3 cases, the course was favorable after evicting the causal substances. For the other 2 cases, intolerance spread to other compounds. Four of the patients changed their work situation because of the chemical odor intolerance. DISCUSSION: The diagnosis is clinical. Different pathogenic hypotheses have been put forward in the literature: immunological, toxic, neurobiological, psychological, and psychiatric mechanisms have been proposed. The mechanism is probably multifactorial but psychological factors appear to play an important role either as predisposing or triggering factors. CONCLUSION: Due to the social and occupational consequences of chemical odor intolerance, better knowledge of its prevalence and mechanism would be most helpful in managing these patients.

Adult↗
PubMed1997

A 5-min running field test as a measurement of maximal aerobic velocity.

Based on a theoretical approach from world record running data, we have previously calculated that the most suitable duration for measuring maximal aerobic velocity (Vamax) by a field test was 5 min (Vamax(5)). The aim of this study was, therefore, to check this hypothesis on 48 men of various levels of physical fitness by comparing (Vmax(5)) with (Vamax) determined at the last step of a progressive treadmill exercise test when the subject felt exhausted (Vamax(t)) and during a test on a running track, behind a cyclist (following an established protocol) (Vamax(c)). For each test, (VO2max) was also measured by a direct method on a treadmill (VO2max(1)) and calculated by an equation for field tests (VO2max(5) and VO2max(c)). The Vamax(5) [17.1 (SD 2.2) km.h-1] and (Vamax(c)) [(18.2 (SD 2.4) km.h-1] were significantly higher than (Vamax(t)) [16.9 (SD 2.6) km.h-1; P < 0.001]. The (Vamax(t)) was strongly correlated with (Vamax(5)) (r = 0.94) and (Vamax(c)) (r = 0.95) (P < 0.001). The best identity and correlation between (Vamax(5)) and track performances were found in the runners (n = 9) with experience over a distance of 3,000 m. The VO2max(5) and (VO2max(c)) were higher than VO2max(t) (+ 5.0% and + 13.7%, respectively; P < 0.001) and VO2max(t) was highly correlated with Vamax(5) (r = 0.90; P < 0.001). These results suggest that the 5-min field test, easy to apply, provided precise information on Vamax and to a lesser degree on VO2max.

Adolescent↗
PubMed1997

[Is a 11-year-old tennis player indifferent to competition stress?].

BACKGROUND: In adults, competition generates a relatively important level of stress. This could be revealed by psychological questionnaires and adrenocortical responses. This study was aimed to evaluate the load of stress in young tennis players in situations of competition compared to that observed during a training session. POPULATION AND METHODS: The 16 best young tennis players of the Auvergne area (mean age: 10.9 +/- 1.7 years) entered the study. The degree of anxiety was measured with the aid of the Martens' SCAT questionnaire and the result of salivary cortisol testing during a training session, and after each of the three competition rounds of the Auvergne championship (three samples were collected at each time: at rest, before and after exercise. RESULTS: Regarding the degree of anxiety, no significant difference was found between the competition and the training session. Cortisol levels did not change during the training session: during the competition, same moderate increase (less than 50%, P < 0.05) was noted for the first two rounds between rest and post-competition values. No difference was found at the third round. CONCLUSION: The high levels of stress described in adults are not found in young tennis players.

Age Factors↗
PubMed1997

Maximal aerobic velocity measured by the 5-min running field test on two different fitness level groups.

The aim of the study was to verify the validity and the accuracy of the 5-min running field test (5RFT) relatively to the classical treadmill test. Two groups of subjects were tested, the first one being made of sub-elite runners (G1, n = 18) and the second one of athletes of other individual or collective disciplines (G2, n = 23). To check the field technique, maximal aerobic velocity (vamax) and an approached VO2max calculated from vamax during the 5RFT were compared with the corresponding values directly determined during a treadmill test. vamax obtained on treadmill (vamax(t)) or during a 5RFT (vamax(5)) were significantly higher in G1 than in G2 (+3.7 km.h-1 and +3.6 km.h-1 among the test). In each group, the difference between vamax(t) and vamax(5) was not significant (19.4 +/- 1.0 vs 19.5 +/- 0.9 km.h-1 in G1; 15.7 +/- 2.2 vs 15.9 +/- 1.2 km.h-1 in G2). A significant correlation was found between vamax(t) and vamax(5) (slope = 0.92; r = 0.86 in G1; slope = 0.71; r = 0.84 in G2). In each group, the approached VO2max(5) was significantly higher than VO2max(t) (respectively 67.8 +/- 2.9 vs 63.7 +/- 3.5 in G1; 54.8 +/- 3.9 vs 52.0 +/- 3.2 ml.min-1.kg-1 in G2. Weak but significant correlations were found between VO2(t) and vamax(5) (r = 0.69 and r = 0.56 respectively in G1 and G2). In conclusion, the 5RFT allows to measure vamax accurately whatever the physical fitness of the subjects but more closely in runners than in non-runners. The low correlation between VO2max(t) and vamax(5) for both groups indicates that a vamax running field test is specific and cannot evaluate VO2max with reasonable accuracy whatever the group, runners or non-runners.

Adult↗
PubMed1996

[Seroprevalence of markers of viral hepatitis A, B and C in hospital personnel at the Clermont-Ferrand University Hospital Center].

OBJECTIVES: Evaluate risk of hepatitis A, B and C infection and anti HBV vaccination policy in hospital personnel. METHODS: A sample of 440 health care workers (7.5% of the personnel at the Clermont-Ferrand University Hospital) representing 74.5% people directly involved in health care and 25.5% other workers were selected at random and stratified by work classification and age. A questionnaire was used to establish personal data on viral hepatitis status and blood samples were drawn for serological tests. RESULTS: Seroprevalence for hepatitis A was 52% with no significant difference between health care and other workers. For hepatitis B, 88.3% of the population had been vaccinated and anti-HBs titre was > or = 10 mIU/ml for 91.6% and > or = 50 mIU/ml for 86.1%. Seroprevalence for anti-HBc was 7% and none of the subjects were positive for HBs antigen. Anti-hepatic C antibodies were found in 2 health care workers (0.7%). CONCLUSION: These findings emphasize the need to persue further preventive actions against hepatitis A, B and C and the requirement for continued efforts in elementary hygiene.

Adult↗
PubMed1996

Determination of maximum aerobic velocity by a five minute test with reference to running world records. A theoretical approach.

Field measurement of the maximal aerobic velocity (MAV) is closely linked to effort-duration then to the used protocol. We construct the relationship between running speed and running-duration logarithm from running world records. It appears a noteworthy point at 4.97 minutes, to be suggested as MAV duration point. By agreement, MAV could be measured on field by a five minute test whatever the sport may be.

Aerobiosis↗
PubMed1996

Heart rate recording method validated by whole body indirect calorimetry in 10-yr-old children.

The aim of the study was to validate the heart rate (HR) recording method against whole body indirect calorimetry in prepubertal children. Nineteen 10.5-yr-old healthy children (10 boys, 9 girls) participated in this study. HR and energy expenditure (EE) were recorded through laboratory tests. Individual relationships between HR and EE were computed (equation established in laboratory). Several models were tested and validated from 24-h measurements of EE and HR by whole body indirect calorimetry. The best fit was obtained with individual polynomial relationships. Mean differences between predicted (equation established in laboratory) and measured total daily EE averaged 7.6 +/- 20.1%. The causes of the differences and the means of improving the accuracy of the prediction equation are discussed.

Calorimetry, Indirect↗
PubMed1973

[Not Available].

Explore the source record for details and available documents.

Child Welfare↗