INSIDE SPORTS NUTRITION

A carbohydrate mouth-rinse may help reduce perceived fatigue and provide a performance advantage for athletes during events lasting < 75 min. Carb rinsing may also benefit athletes who have GI issues, for example at certain points during and in the later stages of an ultraendurance event.

How does carbohydrate work without ingesting it? The presence of carbohydrate in the mouth triggers oral carbohydrate receptors to send positive signals to the brain that may, in turn, modify perception and neuromotor response to fatigue. The end result is being able to sustain a faster pace or higher power output in an otherwise fatigued state (i.e. glycogen depleted).

Rinsing the mouth with a carbohydrate electrolyte beverage for 5 seconds during high intensity intermittent or sustained activities lasting 30-75 minutes has been shown to improve performance by 2-3% in some studies. A 2-3% improvement may sound small but is often meaningful in competitive events. Note – results may vary between individuals and are more pronounced in a fasted state or when fatigued or glycogen depleted.

A recent review included 13 studies that examined the benefits of a carbohydrate mouth rinse on cycling time trial performance and found improvements in mean power output with carb rinsing but not time to complete the trial when compared to a placebo.

Another study examined the use of a carbohydrate mouth rinse in fifteen, female runners (not using OCPs, & during the 3rd-10th day of the MC) during a 60-minute time trial on the track. The authors found no difference between the carb mouth rinse and placebo under fasted conditions.

So, while the research outcomes are mixed, it certainly can’t hurt to try it!

How to implement it:

Swish a sports drink for ~5 seconds and then spit (just watch for the person next to you), every ~10 minutes during the race.

Note that the effects of carb rinsing may not last long and the purpose of using the rinse is to delay the onset of fatigue so ingesting CHO is a better strategy if feasible, for longer duration events > 60-75 min.

PMID 29997738; 28678622; 30056753; 29266092; 30793252, AND Sports Nutrition Handbook