Autonomy in consumer choice.

We propose that autonomy is a crucial aspect of consumer choice. We offer a definition that situates autonomy among related constructs in philosophy and psychology, contrast actual with perceived autonomy in consumer contexts, examine the resilience of perceived autonomy, and sketch out an agenda for research into the role of perceived autonomy in an evolving marketplace increasingly characterized by automation.

The past, present, and future of consumer research.

In this article, we document the evolution of research trends (concepts, methods, and aims) within the field of consumer behavior, from the time of its early development to the present day, as a multidisciplinary area of research within marketing. We describe current changes in retailing and real-world consumption and offer suggestions on how to use observations of consumption phenomena to generate new and interesting consumer behavior research questions. Consumption continues to change with technological advancements and shifts in consumers' values and goals. We cannot know the exact shape of things to come, but we polled a sample of leading scholars and summarize their predictions on where the field may be headed in the next twenty years.

Change in serum sodium concentration during a cold weather ultradistance race.

OBJECTIVE: To investigate change in serum sodium concentration and its potential causes during a cold weather ultradistance race. DESIGN: Descriptive research. SETTING: A 100-mile (161-km) race over a snow-packed course in the Alaskan wilderness. Athletes competed in 1 of 3 divisions: foot, bike, or ski. PARTICIPANTS: Twenty athletes (11 runners, 6 cyclists, 3 skiers) volunteered for the study. INTERVENTIONS: None. MAIN OUTCOME MEASURES: Subjects were weighed and had blood drawn for hematocrit, serum sodium, serum aldosterone, and plasma arginine vasopressin concentrations pre- and postrace. Fluid and sodium intake were determined by race dietary analysis. RESULTS: Serum sodium concentration decreased significantly prerace (140.8 +/- 1.2 mmol/L) to postrace (138.4 +/- 2.2 mmol/L), although no athletes were classified as hyponatremic. Mean weight loss was significant during the race (-1.2 kg), although 1 athlete maintained his weight, and 3 athletes gained small amounts of weight (0.2 kg, 0.2 kg, and 0.5 kg, respectively). Hematocrit decreased significantly prerace (42.2 +/- 3.5) to postrace (40.3 +/- 4.1). Plasma arginine vasopressin and serum aldosterone increased significantly during the race (2.6 +/- 0.7 to 6.0 +/- 4.6 pg/mL and 5.1 +/- 2.6 to 40.8 +/- 25.1 ng/dL, respectively). Fluid consumption was 300 +/- 100 mL/h, and sodium intake was 310 +/- 187 mg/h. CONCLUSIONS: Decreased serum sodium concentration after a cold weather ultradistance race was due to fluid overload caused by excessive fluid consumption. Current recommendations that ultradistance athletes consume 500 to 1000 mL/h may be too high for athletes competing in the extreme cold.

Hyponatremia in a cold weather ultraendurance race.

We assessed the incidence and etiology of hyponatremia in the 100-mile (161 km) Iditasport ultramarathon. Subjects (8 cyclists, 8 runners) were weighed and serum sodium was measured pre- and post-race. Race diets were analyzed to determine fluid and sodium consumption. Subjects were split by post-race serum sodium concentration into hyponatremic and normonatremic groups for statistical analyses. Seven of 16 subjects (44%) were hyponatremic. The hyponatremic group exhibited a significant decrease in serum sodium concentration (137.0 to 132.9 mmol/L), and the normonatremic group experienced a significant decrease in weight (82.1 to 80.2 kg) pre- to post-race. The hyponatremic group drank more fluid per hour (0.5 versus 0.4 L/h) and consumed less sodium per hour (235 versus 298 mg/h) compared to the normonatremic group. In conclusion, hyponatremia is common in an ultraendurance race held in the extreme cold, and may be caused by excessive fluid consumption and/or inadequate sodium intake.