Investigating the truth behind sports drinks
Rhodes Scholarship recipient Braden O’Neill is a third-year MD student at the University of Calgary currently on a leave of absence to study at the University of Oxford in the Department of Primary Care Health Sciences.
The Rhodes Scholarship, often dubbed the world’s most prestigious scholarship, is a postgraduate award supporting exceptional students and the academic elite. The scholarship includes tuition, college fees, and a stipend covering living expenses for two to three years of study at the University of Oxford. O’Neill is the 11th University of Calgary student to receive the scholarship since 1969. Once he has completed his studies at Oxford, he will return to the University of Calgary to complete his MD degree.
With the Olympics nearly upon us, and the Tour de France just having wrapped up, sport performance is the hot topic right now. Even our office here in Oxford – normally a hotbed of discussion about relative risks and numbers needed to treat – is abuzz with talk of who has tickets to what, and if Usain Bolt is really going to repeat his titles in the 100m and 200m.
A combination of Olympic fever and recent reports that being sedentary is really bad for us has people all over dusting off their runners and racquets and deciding to get back in shape.
And after a long workout there’s nothing quite like a specially-formulated sports drink to replace those electrolytes and help you recover.
Whether it’s ‘faster, stronger, for longer’, ‘enhances recovery’, or ‘gives you that extra boost’, sports product marketing is everywhere. Even the official drink of the Olympics this year is Powerade, whose ads claim that ‘Water is Not Enough’.
One of the research groups I work with here – the Centre for Evidence-Based Medicine – recently completed a study on sports performance products which I had the great privilege of being a part of. What we found didn’t quite support all those bold claims.
You can see the series of studies here – released last Thursday in the British Medical Journal (BMJ) – and we also helped with an hour-long BBC Panorama investigative journalism report on ‘The Truth Behind Sports Products’.
Here’s how this worked:
We poured through magazine adverts and found all the ones about sports products. We then looked at the websites for all these products, and extracted all the evidence that companies report backs up their claims. Then, we contacted all the companies and asked them if they agreed that they were making certain claims, and asked if they had any more evidence to back them up. There were lots of interesting responses, and you can see all their responses in a web appendix to the articles.
My personal favourite was from Nike, who directed our attention to a video of a shoe with a voice-over of someone explaining how it worked. Dear Nike: in a field where ‘high quality evidence’ means an appropriately powered randomized controlled trial, a video of a shoe doesn’t quite cut it.
Overall, here’s what we found:
Of 431 studies we assessed for quality and risk of bias, there were only three that were of sufficient quality to be able to trust their results. Most of the studies companies reference to underpin their claims are narrative reviews or position papers – in other words, expert opinion, which is the lowest level of evidence.
Then we went a bit further, and looked at specific common sports myths and the evidence behind them:
‘Branched chain amino acids improve performance or recovery after exercise’ No objective performance improvements, but there is decent evidence that people report that they help. (you can decide how to interpret that finding for yourself!)
‘Energy drinks with caffeine and other compounds improve sports performance’ Caffeine improves performance, if you want to abstain from it for seven days before you use it, and only if you are going to be exercising for more than 60 minutes at high intensity.
‘You should drink before you feel thirsty’ Ridiculous. Absolutely ridiculous. Your body is awfully good at regulating this and telling you when you need to drink something. Listen to it.
‘Urine colour to assess dehydration’ Surprisingly useless, unless you have been trained to be able to do this.
‘Compression garments improve performance or enhance recovery’ Maybe, if you want to wear them continuously for 24 hours after a workout.
‘Carbohydrate and protein combinations improve post-workout performance and recovery’ Useless. Stick to delicious Alberta beef instead.
So there you have it, just in time for the Olympics.
Our conclusions? Get some shoes you find comfortable and want to wear, and if you’re thirsty after exercising, have some water.
It’s all in the evidence.
Proud University of Calgary Medicine Student
Follow me on Twitter @BradenONeill