Alcohol ingestion and man's ability to adapt to exercise in a cold environment

Previous work from this laboratory indicated that when alcohol was ingested prior to performing two hours of mild exercise in a cold environment, subjects experienced greater heat loss and lower blood glucose levels. The present study expanded the protocol to three hours in order to establish if these detrimental effects continued when blood alcohol levels declined. Young, male volunteers (n = 6) ingested water, water and alcohol (2.5 ml/Kg) or water, alcohol (2.5 ml/Kg) and dextrose (50 gm/150 ml water) on different occasions. The 3 treatments were administered by a balanced design. Following fluid ingestion, the subject performed intermittent, bicycle work (40% VO2max) with a 20 min work--10 min rest pattern for 3 hr. in a -5 degrees C environment. VO2, R, and blood glucose data did not reveal any significant metabolic effects of alcohol. The water-alcohol ingestion resulted in a peak blood level (13.05 +/- 2.34 mM l-1) after 69 +/- 39 min. During the third hour there was a decline to 60% of the peak value. With dextrose, the peak level was less (9.29 +/- 2.62 mM . l-1) (p less than or equal to 0.05) and occurred almost one hour later (p less than or equal to 0.05). Generally the alcohol-dextrose data were similar to the previous study in that the alcohol treatment resulted in a significantly greater heat loss (p less than or equal to 0.05). During the third hour the skin and core temperatures remained constant in the control and alcohol-dextrose treatments; however, in the alcohol series the values rose and approached control levels. The study confirmed that moderate levels of blood alcohol can impair thermoregulation while performing mild exercise in a cold environment and thus alcohol ingestion prior to any activity in a cold environment is contraindicated. However, the impairment dissipates when the blood alcohol is metabolized. When alcohol is ingested with dextrose, the alcohol effects are reduced.