Furthermore, notwithstanding other effects of
small to moderate amounts of alcohol, these
drinks might be useful in encouraging large fluid
intakes in dehydrated athletes. However, drinks
with more a concentrated alcohol content are not
advised, since the combination of a smaller fluid
volume and a greater alcohol intake will reduce
the rate of effective fluid replacement. Neverthe-
less, when aggressive rehydration is required,
the planned intake of fluids containing sodium,
or fluid intake in conjunction with sodium-
rich foods, provides a more reliable strategy to
replace fluid losses (see Chapter 19).
Glycogen storage
Since alcohol has a number of effects on the inter-
mediary metabolism of carbohydrate, it is possi-
ble that postexercise intake might impair the
restoration of depleted glycogen stores. In the
absence of carbohydrate intake, alcohol intake is
known to impair the carbohydrate status of the
liver by inhibiting hepatic gluconeogenesis and
increasing liver glycogenolysis. Alcohol intake
has been reported to impair muscle glycogen
storage in rats following depletion by fasting or
exercise (for review, see Palmer et al.1991). The
effect of alcohol intake on muscle glycogen
storage in humans was recently studied by Burke
and co-workers (in press), who undertook two
separate studies to examine refuelling over 8 h
and 24 h of recovery from a prolonged cycling
bout.
In these studies, athletes undertook three dif-
ferent diets following their glycogen-deleting
exercise: a control (high carbohydrate) diet, an
alcohol displacement diet (kept isoenergetic with
the control diet by reducing the carbohydrate
intake) and an alcohol+carbohydrate diet
(alcohol added to the control diet). In the two
diets containing alcohol, the athletes were
required to consume 1.5 g alcohol · kg–1body
mass of alcohol in the 3 h immediately after exer-
cise (e.g. ª100 g alcohol or 10 standard drinks).
Muscle glycogen storage was significantly
reduced on the alcohol displacement diets in
both the 8 h and 24 h study compared with the
410 nutrition and exercise
high carbohydrate diets. There was a trend
towards a reduction in glycogen storage over 8 h
of recovery with alcohol+carbohydrate diet;
however, glycogen storage on the alcohol+car-
bohydrate diet on the 24-h study was identical to
the control diet. Therefore, there was no clear evi-
dence of a direct impairment of muscle glycogen
storage by alcohol when adequate substrate was
provided to the muscle; however, this may have
been masked by intersubject variability.
The results of these studies suggest that the
major effect of alcohol intake on postexercise
refuelling is indirect, that high intakes of alcohol
are likely to prevent the athlete from consum-
ing adequate carbohydrate intake to optimize
muscle glycogen storage. In general, athletes
who participate in alcoholic binges are unlikely
to eat adequate food or make suitable high-
carbohydrate food choices. Furthermore, food
intake over the next day may also be affected as
the athletes ‘sleep off their hangover’. Further
studies are needed to determine the direct effect
of alcohol on muscle glycogen storage.Other effects
Alcohol is known to exert other effects which
may impede postexercise recovery. Many sport-
ing activities are associated with muscle damage
and soft tissue injuries, either as a direct conse-
quence of the exercise, as a result of accidents, or
due to the tackling and collisions involved in
contact sports. Standard medical practice is to
treat soft tissue injuries with vasoconstrictive
techniques (e.g. rest, ice, compression, elevation).
Since alcohol is a potent vasodilator of cutaneous
blood vessels, it has been suggested that the
intake of large amounts of alcohol might cause
or increase undesirable swelling around dam-
aged sites, and might impede repair processes.
Although this effect has not been systematically
studied, there are case histories that report these
findings. Until such studies are undertaken, it
seems prudent that players who have suffered
considerable muscle damage and soft tissue
injuries should avoid alcohol in the immediate
recovery phase (e.g. for 24 h after the event).