European journal of applied physiology and occupational physiology
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Eur J Appl Physiol Occup Physiol · Jan 1996
Restoration of fluid balance after exercise-induced dehydration: effects of food and fluid intake.
This study investigated the effects of post-exercise rehydration with fluid alone or with a meal plus fluid. Eight healthy volunteers (five men, three women) were dehydrated by a mean of 2.1 (SEM 0.0)% of body mass by intermittent cycle exercise in a warm [34 (SEM 0) degrees C], humid [55 (SEM 1)% relative humidity] environment. Over 60 min beginning 30 min after exercise, the subjects ingested a commercially-available sports drink (21 mmol.l-1 Na+, 3.4 mmol.l-1 K+, 12 mmol.l-1 Cl-) on trials A and B: on trial C a standard meal [63 kJ.kg-1 body mass (53% CHO, 28% fat, 19% protein; 0.118 mmol.kJ-1 Na+, 0.061 mmol.kJ-1 K+)] plus drink (1 mmol.l-1 Na+, 0.4 mmol.l-1 K+, 1 mmol.l-1 Cl-) were consumed. ⋯ This may have been due to the larger quantities of Na+ and K+ ingested with the meal [mean 63 (SEM 4) mmol Na+, 21.3 (SEM 1.3)mmol K+] than with the drink [mean 42(SEM 2)mmol Na+, 6.8 (SEM 0.4)mmol K+]. There was no difference between trials B and C in any of the measured blood parameters, but urinary Na+ and K+ excretion were both higher on trial C and B. These results suggest that post-exercise fluid replacement can be achieved by ingestion of water if consumed in sufficient volume together with a meal providing significant amounts of electrolytes.
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Eur J Appl Physiol Occup Physiol · Jan 1996
Randomized Controlled Trial Clinical TrialThe effects of buffer ingestion on metabolic factors related to distance running performance.
We examined the effects of sodium bicarbonate (BIC) and sodium citrate (CIT) ingestion on distance running performance. Seven male runners [mean VO2max = 61.7 (SEM 1.7) ml.kg-1.min-1] performed three 30-min treadmill runs at the lactate threshold (LT) each followed by a run to exhaustion at 110% of LT. The runs were double-blind and randomly assigned from BIC (0.3 g.kg body mass-1), CIT (0.5 g.kg body mass-1) and placebo (PLC, wheat flour, 0.5 g.kg body mass-1). ⋯ Blood [HCO3-] was significantly higher (P < or = 0.05) during exercise for BIC compared to PLC. TIME-EX was not significantly different among treatments: BIC 287 (SEM 47.4)s; CIT 172.8 (SEM 29.7)s; and PLC 222.3 (SEM 39.7)s. Despite the fact that buffer ingestion produced favourable metabolic conditions during 30 min of high intensity steady-state exercise, a significant improvement in the subsequent maximal exercise run to exhaustion did not occur.
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Eur J Appl Physiol Occup Physiol · Jan 1996
Randomized Controlled Trial Clinical TrialPhysical work capacity in dynamic exercise with differing muscle masses in healthy young and older men.
Ten young (aged 23-30 years) and nine older (aged 54-59 years) healthy men with similar estimated limb muscle volumes performed, in random order, three different types of ergometer exercise tests (one-arm cranking, two-arm cranking, and two-leg cycling) up to the maximal level. Values for work load (WL), peak oxygen consumption (V0(2)), peak heart rate (HR), peak ventilation (V(E)), respiratory gas exchange ratio (R), recovery blood lactate concentration [La-], and rating of perceived exertion (RPE) were compared between the age-groups in the given exercise modes. No significant age-related differences in WL, peak V0(2), peak HR, R, [La-], or RPE were found in one-arm or two-arm cranking. ⋯ In summary, the older men with similar sizes of estimated arm and leg muscle volumes as the young men had a reduced physical work capacity in two-leg cycling. In one-arm or two-arm cranking, no significant difference in work capacity was found between the age-groups. These results indicate, that in healthy men, age, at least up to the 6th decade of life, is not necessarily associated with a decline in physical work capacity in exercises using relatively small muscle groups, in which the limiting factors are more peripheral than central.
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Eur J Appl Physiol Occup Physiol · Jan 1996
Physiological and subjective responses to thermal transients of exercising subjects dressed in cold-protective clothing.
In cold conditions variations in the physical activity of clothed individuals and rest periods in a moderate temperature may result in a disturbance of heat balance and thermal comfort of the individual, in particular when sweating occurs. The purpose of the study was to examine thermal responses in persons dressed in winter clothing during changes of exercise intensity (high to low) and ambient temperature, and to investigate whether there were any effects on these responses due to fibre material (wool and synthetic). Two types of transient condition were studied, an exercise level transient (E) and a temperature transient (T). ⋯ The wool fibre material resulted in a slightly higher mean skin temperature (about 0.3 degree C) during exercise, but no differences in subjective responses were found. The rest period had only a small influence on the subsequent thermal responses. The interindividual variations in thermal responses were large.