Heart rate, alveolar gas partial pressures and blood lactate (BLa) concentration were measured during synchronized swimming in six subjects. During upside-down breath-holding lasting 50 s, heart rate fell progressively from 98 +/- 14 to 70 +/- 7 beats min-1 (mean +/- S.D.). While breath-holding during the compulsory figures, the subjects' heart rate increased to 142 +/- 5 beats min-1 and then fell to 72 +/- 10 beats min-1. At the end of breath-holding, alveolar oxygen pressure had fallen significantly (60 mmHg), whereas alveolar carbon dioxide pressure showed only minor changes (48 mmHg). The increase in BLa concentration due to the execution of compulsory figures was approximately 1 mM; in the free routines, BLa concentration increased by 3.4 +/- 0.5 mM. The net energy cost of completing a compulsory figures lasting 45 s was 34.6 kJ.

This study examined the physiology of the 1-mile walk test as administered in the field with 16 (7 M, 9 F) older adults (mean age 66.1 ± 5.9 yrs). Physiologic data were obtained via a Cosmed K2 miniaturized O2analyzer with telemetric capabilities during a maximal treadmill (TM) test and a 1-mile walk test (MWT). Oxygen consumption (ml · kg−1· min−1), minute ventilation (L · min−1), and heart rate (b · min−1) values obtained at maximal levels on the TM were 25.6 ± 7.6, 57 ± 17, and 155 ± 16, respectively. The measured V̇O2submax during the MWT was 18.5 + 5, V̇Esubmax was 44 ± 10, and HR submax was 140 ± 19. The subjects were able to hold 74% of the V̇O2max, 81% of V̇Emax, and 91% of HR max. An upward drift for HR and V̇Ewas noted while V̇O2remained constant throughout the MWT. The MWT with older subjects requires a vigorous level of metabolic and cardiorespiratory intensity. For healthy older adults who have been properly screened for hidden metabolic and cardiovascular diseases, participation in the MWT appears feasible.

The purpose of this study was to examine the relationship between selected physiological variables and lactate accumulation at the end of a l-mile walk test (MWT) in older women (mean ± SD: 64.6 ± 3.1 years). Seventeen women with a peak (ml · kg-1 · min-1) of 21.1 ± 4.2 volunteered to participate. Physiological data were obtained via a COSMED K2 miniaturized O2 analyzer with telemetric capabilities during a maximal treadmill (TM) test and MWT. Blood samples were obtained from the ear lobe for lactale analysis immediately before and after the treadmill test and MWT. Subjects performed the MWT in 15.4 ± 1.4 min at an intensity of 76% of peak and 86% of HRmax. The blood lactate accumulated at the end of the MWT was 2.61 ± 1.47 mmol/L. Peak lactate following the maximal treadmill test was 3.8 ± 1.42 mmol/L. HR during the test was significantly related with blood lactate (r= .65, p< .01). The lactate values observed during the lest suggest that the I-mile walk test is a suitable field testing procedure for older women.

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