Carbonated drinks and exercise
Quote:
> Books giving nutritional advice for hiking trips commonly state "do
> not take fizzy drinks" or "allow carbonated drinks to go flat before
> consumption".
> Nobody has given me a plausible scientific explanation for the advice
> and I've often had a canned drink on hill walking expeditions with no
> ill effect.
> The best explanation I've heard is that in an activity like running -
> if a can of coke is drunk while still on the move, the gas-bloat may
> be uncomfortable.
> But consumed at a meal break surely the gas will be belched out - I
> understand the volume of co2 in 100ml of cola is about 200ml of which
> probably about 40ml is released when the can is opened.
> I know there are other debates around topics like the suggestion that
> caffeine (in cola drinks) is a diuretic but lets handle that
> discussion seperately.
> Is it a myth or can anyone propose a good reason why carbonated drinks
> are inappropriate - ideally with scientific support rather than
> opinion or hearsay...
The effects of a carbonated carbohydrate drink on gastric emptying,
gastrointestinal distress, and exercise performance.
* Zachwieja JJ,
* Costill DL,
* Beard GC,
* Robergs RA,
* Pascoe DD,
* Anderson DE.
Div. of Metabolism, Washington U. School of Medicine, St. Louis, MO
63110.
To determine the effect of a carbonated carbohydrate (CHO) drink on
gastric function and exercise performance, eight male cyclists
completed four 120-min bouts of cycling. Each bout consisted of a 105-
min ride at 70% VO2max followed by a 15-min self-paced performance
ride. During each trial, one of four test solutions was ingested:
carbonated CHO (C-10%), noncarbonated CHO (NC-10%), carbonated non-CHO
(C), and noncarbonated non-CHO (NC). Following the performance ride,
the subjects had their stomach contents removed by aspiration. There
were no significant differences in gastric emptying (GE) except for
Trial C-10%, which averaged 13.3% less than NC. However, there was no
difference in the perception of gastrointestinal comfort between this
trial and any other. Average power output during the performance ride
was not significantly different between carbonated and noncarbonated
trials, or between CHO-fed and no-CHO trials; however, the subjects
worked at a greater intensity when fed CHO. Finally, acid base status
did not change when a carbonated drink was ingested. This indicates
that adding carbonation to a sport drink does not significantly alter
gastric function, the perception of GI comfort, or exercise
performance.
