Apr 2016 23

Spit or swallow?

By: Dave Wheeler

You couldn't make it up,

This week an article by Lindsay Bottoms (yup) of the University of Hertfordshire has gone viral. It's subject: why spitting is as good as swallowing.

In fairness, the actual subject is more decent than I'm suggesting - it's about carbohydrate drinks for athletes.


Sports drinks

There's been a consistent and growing body of research since the mid 80's confirming what most athletes have known for ages - that sports drinks help you to keep going for longer.

Sports drinks replenish the carboydrate burned during exercise so that continued exercise can be fuelled. This becomes important for exercise that lasts a decent length of time - in other words endurance

In the late 90's scientists found that sports drinks could also radically improve performance for high intensity shorter duration exercise.

The best known study confirming the benefits of carbohydrate sports drink is from the University of Birmingham in 1997 by Dr Asker Jeukendrup of the Gatorade Sports Science Institute. This looked at cyclists on a 40km time trial (typically around 1 hour of cycling) found that:

  • taking carbohydrate in glucose form delays the onset of fatigue
  • it can improve performance (time) by 2.3%

The one downside was that the study also found that ingesting too much glucose can upset the stomach.


Spitting is as good as swallowing

Because of the issue of the potential for gastro problems, research then moved on to whether rinsing the mouth out for 5 seconds then spitting the sports drink out was as good as swallowing a mouthful.

In a repeat study in 2004 Jeukendrup showed that swilling sports drinks also improved performance, though he was unable to account for the improvement by any metabolic means and put the improvement down to "motivational" factors.

Lots of studies followed, with the best known being by Carter in 2003 (of the University of Birmingham) which suggested that rinsing the mouth with carbohydrate drink may stimulate nerve receptors in the mouth which affects the area of the brain responsible for motivation - and its this that accounts for the improved performance.

The most recent research by Lindsay Bottoms from the University of Hertfordshire which was published last week looked at whether rinsing, or "spitting", had a noticeable effect on sports that require skill, accuracy and tactics, not just endurance.

The researchers studied 12 fencers doing repeated lunges (for accuracy) and found that there was, indeed, an increase in accuracy.

So it seems that swililng sports drinks and spitting out can improve not only endurance, but accuracy.

Who cares? Well it's good news if you get stomach problems from glucose gels and the like. It's also good for sports where you're standing around waiting all day and are then expected to perform at your peak for a short burst. It means you don't have to eat loads of carbs which might sit "heavy" in your stomach.