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Biomedical subjects

A Quirion

Publications and source records attributed to A Quirion.

31 records · Page 2Linked to original sources
PubMed1986

[Endurance bicycle ergometry at 0 degrees C: cardio-respiratory and metabolic course].

The purpose of the present study is to determine the physiological and metabolic variations during and after an exhaustive exercise in different thermal conditions (0 degree C and 20 degrees C). For the eleven experimental subjects, the maximal power output is the same at 0 degrees C and 20 degrees C: 330 +/- 30 W (Mean +/- s). The heart rate is lower (bradycardia) at rest, exhaustion, and recovery. However, these differences are only significant (p less than 0.05) at exhaustion. The oxygen consumption and pulmonary ventilation is higher at 0 degree C in comparison with the measurements at 20 degrees C. The blood lactate concentrations are significantly lower at 0 degree C and we observe the inverse phenomenon for the bicarbonates. The bases excess was significant at 4, 6 and 10th minute of recovery time. These values are higher for the measurements taken at 0 degree C. The results have shown that the cold stress after an exhaustive exercise and during recovery, can induce a physiological and metabolic response unlike of those at 20 degrees C.

Adolescent↗
PubMed1986

[Hormonal responses to repeated lactic acid anaerobic exercise in male subjects].

The hormonal response to repeated lactic acid anaerobic exercise was investigated in 6 young male adults. The exercise protocol consisted of 3 one-minute bouts of voluntary maximal effort, each bout being separated from the subsequent one by a two-minute rest period. Venous blood samples were obtained at rest and at the end of each of the 3 work bouts, as well as following 15 minutes of recovery. A marked increase in plasma catecholamine concentrations was observed in response to the repeated exercise bouts, the rise being more important for the adrenaline (x 22) than the noradrenaline (x 10) concentrations. A progressive increase in plasma somatotropin hormone was observed between the first and the last venous sampling. Moreover, a delayed rise in plasma cortisol, insulin, prolactin, and androstenedione was also observed. Hormonal concentrations of LH, FSH, DHEA-SO4, testosterone, SHBG and testosterone/SHBG ratio were not modified in response to the type of exercise.

Adult↗
PubMed1982

[Effects of cold wind on the response to muscular exercise].

The purpose of the present studies was to determine if the response to exercise is modified by a cold wind. When the subjects exercised in the cold (with or without wind), cheek and forehead temperatures were higher, but the temperature of the nose was lower than in the resting state. The decrease in heart rate, normally observed when cold wind is blown on the face at rest, persisted and even became greater during exercise up to a heart rate of 150 beats/minute. However, this decrease was progressively eliminated as heart rate increased further up to maximum. These results have shown that a cold wind can diminish the heart rate response to submaximal exercise in comparison with a no wind condition (delta up to 20 beats/minute at a heart rate of 150 beats/minute).

Adult↗
PubMed1981

[Intercorrelations and variabilities of heart rate at the rest and during exercise in the evaluation of physical fitness].

It appears that heart rate measured at rest may significantly affect the values obtained during a sub-maximal effort: isometric as well as isotonic. For this study, 24 male subjects were tested, on a 15 and 30 days interval in a laboratory during an isometric effort. The task was to lift and hold with the arms bent, at a standardized angle of 45 degrees, a 12 kg load during a three minute period. The influence of the resting pulse on the isotonic submaximal values were studied on one subject during a period of 30 days. The authors thus suggest that the battery of tests which determine physical aptitude based on the sole criterion of heart rate as measured during a sub-maximal effort (Astrand's PWC-170, Step test, etc.) take into account the variability of the resting values of this parameter.

Adolescent↗
PubMed1981

[Steady state ergometry: fact or fiction].

The steady state is a physiological condition whereby the metabolic requirements are met and the criteria parameters are stable. Four groups of male subjects were evaluated on their VO2 for a one hour duration ergocycle effort at 75%, 50%, 25% and 10% of their maximum individual VO2. Three cardio-respiratory parameters (heart frequency, oxygen consumption, pulmonary ventilation) and one biochemical parameter (lactic acid) were measured The evolution of the control parameters during the task were completed according to the requirements of the literature. For the long-duration efforts (one hour) we notice the absence of a steady-state for the cardio-respiratory parameter. We cannot however rule-out the existence of a steady state for the biochemical parameter for the lighter efforts of 10% and 25% of the VO2 maximum.

Adult↗
PubMed1980

[Review of the literature on myoglobin in the development of exertion and aerobic training].

The myoglobin has the property to store the oxygen at the level of the striated muscle. The histological study of the striated muscles proves that the distribution of myoglobin is neither uniform nor identical in all of the muscular fibres (slow twitch and fast twitch fibres). It has been shown that the myoglobin content increases with endurance training but the opposite effect (decrease) has not been formally demonstrated during a training based on short and explosive exercises.

Muscles↗
PubMedDate not supplied

Lactate threshold determination: a Monte Carlo comparison of two interpolation methods.

A heuristic model of the relation between blood lactate (L) and VO2 during exercise was used to assess the comparative merits of two methods of reference threshold determination: the habitual linear interpolation method (LT), and a new method using inverse parabolic (second degree) interpolation (PT); the new method capitalizes on the demonstrated curvilinear relation between blood lactate and O2 uptake. Both types of interpolated thresholds were computed, and their error evaluated against the "true" 4-mmol lactate threshold. A combined parametric and Monte Carlo investigation showed that parabolic thresholds are generally superior, being less biased and more precise than their linear counterpart.

Exercise↗