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10.1152/japplphysiol.00630.1999.—Some recent studies of competitive athletes have shown exercise-induced hypoxemia to begin in submaximal exercise. We examined the role of ventilatory factors in the submaximal exercise gas exchange disturbance (GED) of healthy men involved in regular work-related exercise but not in competitive activities. From the 38 national mountain rescue workers evaluated (36 ± 1 yr), 14 were classified as GED and were compared with 14 subjects matched for age, height, weight, and maximal oxygen uptake (V˙o 2 max; 3.61 ± 0.12 l/min) and showing a normal response (N). Mean arterial Po 2 was already lower than N ( P= 0.05) at 40% V˙o 2 max and continued to fall until V˙o 2 max (GED: 80.2 ± 1.6 vs. N: 91.7 ± 1.3 Torr). A parallel upward shift in the alveolar-arterial oxygen difference vs. %V˙o 2 max relationship was observed in GED compared with N from the onset throughout the incremental protocol. At submaximal intensities, ideal alveolar Po 2, tidal volume, respiratory frequency, and dead space-to-tidal volume ratio were identical between groups. As per the higher arterial Pco 2 of GED at V˙o 2 max, subjects with an exaggerated submaximal alveolar-arterial oxygen difference also showed a relative maximal hypoventilation. Results thus suggest the existence of a common denominator that contributes to the GED of submaximal exercise and affects the maximal ventilatory response.

A population of 120 healthy voluntary subjects of both genders aged 16-88 was studied using the QAPSE (Saint-Etienne Physical Activity Questionnaire) with the purpose of investigating the factors influencing the relation between MHDEE (mean habitual daily energy expenditure) and VO2max (maximal oxygen uptake) to elucidate the factors accounting for individual variation. The mean of MHDEE obtained was 12,181.9 +/- 4041.9 kJ.d-1. The mean VO2max obtained was 39.9 +/- 13.8 ml.kg-1.min-1. A strong relationship between MHDEE and VO2max (r = 0.916; N = 120; P0.0001) was found. Further, MHDEE seemed to be the greater determinant in the variation of VO2max (89.35%). Other variables were found to be involved in the relation between MHDEE and VO2max for a smaller, but still substantial part: age (6.92%), PAST (exathletes who had considerably reduced or stopped their training) (2.45%), body mass (0.85%), and gender (0.43%). Two variables regarding maximal intensity of activity were not included in the multiple-linear regression analysis. These results suggested that the most important factor in the variation of VO2max is the total quantity of energy expenditure and not only the maximal intensity that could reach the subject.

The objective of this study was to design and validate a working tool for the objective evaluation of daily energy expenditure (DEE) by means of a simple, noninvasive method: the QAPSE (Saint-Etienne Physical Activity Questionnaire), a questionnaire about physical activity (PA) over a period of 7 d (168 h). This eight-page questionnaire is designed to provide a complete picture of the subject's habitual PA without any restriction concerning the activities investigated, nor any specialization in relation to health components. It investigates the five areas of PA during daily life: work or way of keeping occupied, leisure activity (sports and nonsports activities), housework, basic everyday activity, moving about from place to place. Assessment of physical activity was conducted in 115 healthy volunteer subjects of both sexes aged 20-88. The values of mean habitual daily energy expenditure (MHDEE) obtained varied between 6,510 and 24,331 kJ.d-1. The MHDEE were in agreement with the data reported in the literature for various groups differing in respect to level of activity, sex, and age. The study demonstrated the reproducibility of the QAPSE (r = 0.997; N = 20; P0.0001). Its validity was tested in a comparative study between MHDEE and caloric intake (r = 0.576; N = 20; P0.01).

The sickle cell trait (HbAS) does not seem to affect exercise performance. It remains unclear, however, whether the capability to sustain repeated brief maximal effort and recovery by HbAS subjects, is also preserved. To study this, nine HbAS and nine matched controls underwent on two different occasions, a series of four, approximately 2-min duration, maximal cycle exercise tests separated by 20-min recovery periods of either absolute rest (P) or light pedaling (A) as well as an incremental test to exhaustion. In all tests, work performed, heart rate, blood hematocrit, lactate, and serum creatine kinase (CK), lactate dehydrogenase (LDH), and aspartate aminotransferase (GOT) were measured. Performances were similar in HbAS and HbAA subjects in both the predominantly anaerobic and aerobic exercise series. There were no observable differences in work, power, or heart rate in the two groups both during peak exercise or recovery periods. A significant hemoconcentration was observed during P, with hematocrit increasing in HbAS from 46.4 +/- 0.7% to 48.3 +/- 0.4% at the end of the last recovery period. Similar changes were seen in HbAA. Significantly greater fluid losses were found during A (1.3 +/- 0.2 l in A and 0.6 +/- 0.1 l in P for HbAS; P0.001), but fluid losses were similar in each type of recovery in the two groups. Despite similar performance, significantly lower blood lactate concentrations were consistently found in HbAS in each of the three exercise series (P0.001). Lower lactate levels in HbAS were observed only at exercise loads above the lactate threshold during the incremental test (P0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

The purpose of this study was to evaluate the various factors involved in the performances of three groups of swimmers with disabilities. These factors were average VO2max (Av-VO2max) measured during swimming and gliding factors measured by the passive drag. Thirty-four swimmers with disabilities were assigned into three groups ranging from more disabilities to fewer disabilities. The first group (G I) included 13 subjects in wheelchairs, the second group (G II) 10 subjects walking with technical aids, and the third group (G III) 11 swimmers with disabilities walking without any help. For G I, the performances and Av-VO2max were lower (P0.05) than for G II and G III while the passive drag was higher than for G III (P0.05). The performances, Av-VO2max, and passive drag were not statistically different between G II and G III. Some of the swimmers had a pronounced amyotrophia of the lower extremities (i.e., reduced volume of inactive muscles). The height from the top of the head to the beginning of the bilateral amyotrophia was called "height without amyotrophia" (HWA). In the whole group, passive drag was not related to the mass or the height but to the ratio mass/HWA (r = 0.71, P0.01). However, within each group, passive drag was mainly related to the mass (r = 0.63, 0.78, 0.62, P0.01, for G I, G II, and G III respectively). Performances of a 100-m and 400-m swim were mainly related to Av-VO2peak (r = 0.81 and 0.79, P0.01, respectively).(ABSTRACT TRUNCATED AT 250 WORDS)