Exercise condition affects hedonic responses to sodium in a sport drink.

We measured the dose-response effects of drink sodium content (treatments: 0 mmol/l, 18 mmol/l, 30 mmol/l, 40 mmol/l, and 60 mmol/l) on sensory perception and palatability in athletes at four time points: in a sedentary laboratory setting (non-exercise context), pre-exercise, and after 60 min and 120 min of aerobic-circuit exercise. Fifty-five triathletes and runners (30 males, 39.7 (8.0 S.D.) years; 25 females, 37.2 (9.2 S.D.) years) sip-tested chilled 6% carbohydrate drinks varying in sodium content during sedentary and pre-exercise conditions and had ad lib access to drinks during exercise conditions. There was a significant intensity discrimination among all sodium levels (p

Impact of beverage acceptability on fluid intake during exercise.

These two studies investigated the impact of beverage acceptability on voluntary fluid intake during exercise and the subsequent impact of exercise on the perception and liking of beverages. In Experiment 1, 49 triathletes and runners first tasted an array of 10 commercially available flavors of a 6% carbohydrate-electrolyte drink (CE) and water (W) to determine the most-acceptable flavor (M) and least-acceptable flavor (L) for each subject. Subjects were subsequently given M, L, or W ad libitum during 180 min of exercise. Drink acceptability was again measured after 90 and 180 min of exercise. Drink intake was measured at 15-min intervals. Intake of M was significantly greater than L and W throughout the first 75 min and significantly greater than W throughout the entire exercise period. In Experiment 2, subjects were given M+W, or L+W, in a two-bottle procedure. Voluntary intake of M and L exceeded W by 318% and 233%, respectively. An unexpected finding was a strong interaction between drink acceptability and exercise state. The acceptability of L increased substantially from sedentary to exercise conditions. These data demonstrated that the flavored, sweetened beverages used in this study, substantially increased voluntary fluid intake over W.

The effects of beverage carbonation on sensory responses and voluntary fluid intake following exercise.

The effects of carbonated beverages on sensory acceptability and voluntary fluid intake after exercise were examined. The level of carbonation in a 6% carbohydrate (CHO) electrolyte drink was systematically varied (0, 1.1, 2.3, and 3.0 volumes of CO2), and its impact was assessed in 52 adults following 30 min of exercise. The perception of carbonation intensity closely tracked the differences in physical carbonation levels presented, with all perceived intensities significantly different from each other (p < .01). Overall sensory acceptability, perceived thirst quenching, and perceived sweetness were significantly lower for 2.3-vol CO2 and 3.0-vol CO2 than for 0-vol CO2 and 1.1-vol CO2 (p < .01). Perceived throatburn was significantly higher for 2.3-vol CO2 and 3.0-vol CO2 than for 0-vol CO2 and 1.1-vol CO2 (p < .01). Total fluid intake for 0-vol CO2 and 1.1-vol CO2 was significantly higher than for 2.3-vol CO2 (p < .05), which was significantly higher than for 3.0-vol CO2 (p < .05). It was concluded that levels of carbonation equal to or in excess of 2.3-vol CO2 negatively impact drink acceptability and voluntary fluid intake.

Hypohydration during exercise in children: effect on thirst, drink preferences, and rehydration.

This study examined changes in children's thirst and drink preferences during exercise-induced hypohydration and their spontaneous rehydration during a 30-min recovery. Twenty-four 9- to 13-year-old children (14 females, 10 males) participated in four intermittent 90-min cycling sessions in the heat (35 degrees C, 20% relative humidity); the sessions differed in the drinks the children were sampling (apple, orange, water, and grape). Thirst and drink preferences were assessed (analog and category scales) while children dehydrated up to about 0.76% of their initial body weight. During 90 min dehydration, there was an increase in thirst intensity for all drinks. The grape was the preferable drink throughout the dehydration phase, but its desirability did not increase as much as the desirability of the orange, apple, and water drinks. During the 30-min recovery, most subjects rehydrated spontaneously, exceeding baseline levels by 0.76 +/- 0.15% (M +/- SEM) for grape, 0.40 +/- 0.15 for apple, 0.71 +/- 0.18 for orange, and 0.48 +/- 0.16 for water. Although full rehydration was achieved with all drinks, the magnitude of rehydration was statistically greater with grape and orange than water and apple (p < .05). It was concluded that mild hypohydration during exercise increased children's thirst and drink desirability. In general, spontaneous overshoot of fluid consumption occurred during recovery.

Odor psychophysics in vertebrates.

The methods used to obtain psychophysical data on the nasal chemosensory systems of all classes of vertebrates are critically reviewed and a summary of the available data on their odor detection and discrimination abilities is provided. Although there are reliable methods for training at least one member of each class to respond differentially to the presence or absence of odor stimuli, very little is known about the limits of the capacity of any of the three major nasal chemosensory systems (olfactory, vomeronasal and trigeminal) to detect pure compounds. Furthermore, studies in which rigorous procedures are followed for both the maintenance of discriminative responding and the presentation of odor stimuli often fail to determine the sensory system(s) mediating the psychophysical results. This lack of information has impeded progress on several fundamental problems in the study of nasal chemoreception.

Behavioral determination of olfactory thresholds to amyl acetate in dogs.

By use of a modified conditioned suppression technique, olfactory thresholds to amyl acetate were determined for four beagle dogs. Using the same odorant and olfactometer and a similar breathing chamber, olfactory thresholds were obtained in eight human subjects. It was determined that the olfactory sensitivity of the dogs was about 2.5 log units better than that of the human subjects.

Interference of hyperleukocytosis on Coulter Counter Model S blood counts: methods for correction.

Hyperleukocytosis leads to an overestimation of the determination by Coulter Counter Model S of erythrocyte count, hemoglobin, MCV and packed cell volume. These overestimations are proportional to the number of leukocytes above a certain limit, and, for the MCV and PCV, depend on the type of leukocytes present. Regression lines have been calculated which allow for correction of the values obtained.

Autoshaping as a psychophysical paradigm: Absolute visual sensitivity in the pigeon.

A classical conditioning procedure (autoshaping) was used to determine absolute visual threshold in the pigeon. This method provides the basis for a standardized visual psychophysical paradigm.