Testing with the Pro's

We often read that taking sport drinks enhances endurance, particularly for ultra-endurance events. But does the same recommendation that is given to an amateur triathlete, runner or cyclist apply to a more advanced or professional athlete? What do the top professionals do in terms of fluid and energy supply throughout events such as an Ironman Triathlon? More importantly, can the limits be pushed, leading to world class performance? These were some of the questions we wanted to investigate.

So, HIGH5 invited top professional triathletes to take part in a simple investigation of our new generation sports drink with 2:1 fructose. The trials took part at the University of Hertfordshire in their Performance Testing Laboratory under the expert supervision of Dr Justin Roberts and his team of skilled physiologists. The athletes arrived, pro bike in hand ready to take on a rather unusual and arduous task – to perform at Ironman race pace whilst consuming concentrated drinks that were 25% greater (in terms of carbohydrate quantity) than their usual strategy.

Once the athlete's bike was rigged to a Computrainer platform for assessment of speed, power and cadence; the athlete undertook resting measurements of oxygen consumption. This was achieved by having the athlete breathe into a large bag (called a Douglas Bag) from which the physiologists deduced how much oxygen and carbon dioxide was being used. After this, our athletes built up to a predicted race pace based on previous performances.

The athletes then had to hold this pace for 3 hours with measurements of oxygen uptake, blood samples and even a questionnaire being undertaken every 30 minutes. After this, our athletes had little time to rest other than to change as they would do under race conditions before going straight into a race pace run for a further gruelling 2 hours, with treadmill speed at 15-16kph. Measurements were taken every 20minutes during the run. Throughout both parts of the investigation, athletes were provided with 1.2L fluid per hour delivering 120g of Energy Drink Caffeine (10% or 2g.min-1) and asked to drink ad lib throughout each hour according to their normal routine. Additional water was available if required.

Whilst there is some debate about the ‘upper limit’ for glucose ingestion, it was certainly interesting to note that the athletes coped very well with the higher amount despite being used to consuming 90g per hour. What the physiologists were also investigating was how much of the drink was being used (or oxidized) – this is known as exogenous carbohydrate oxidation. Essentially if more of the drink is being used, the exogenous oxidation rate will increase.

What was interesting with this is that whilst most people might use about 1.2 - 1.4g per minute of carbohydrate from these sports drinks, our elite athletes were able to use closer to 2.0g per minute – hence generating a higher power output for longer. When this was later put into practice during the 2011 Karnten Ironman Austria, one of the athletes, Marino Vanhoenacker, broke the Ironman world record in a staggering 7hrs 45mins and 58 seconds. This just goes to show that using the right nutrition can pay dividends. The product used in these investigations utilised a unique combination of maltodextrin and fructose, along with caffeine to optimise absorption. The combination of different sugars has been shown to be beneficial to athletes as more of the drink is absorbed and as shown in these laboratory test, more is also used by the athlete.

About Dr Justin Roberts

Dr Justin Roberts is a Senior Lecturer/ Researcher at the University of Hertfordshire, specializing in Performance Nutrition.

He is a BASES Accredited Sport and Exercise Physiologist, and an Accredited Nutritional Therapist (MBANT, NTC, CNHC). Having worked at the British Olympic Medical Centre, Dr Roberts has gained significant experience with high level performance, and more recently has been recognized for his scientific and practical nutritional applications for endurance athletes, including ultra-endurance and expedition events.

Dr Roberts has consulted for various groups, and was Performance Nutrition Advisor to the England Football Squad and Manchester City Football Club.

Having undertaken several Ironman Triathlons, Dr Roberts himself takes part in extreme challenges, and recently completed the ‘Toughest Footrace on Earth’ - the Marathon des Sables, a gruelling 150-mile race through the searing heat of the Sahara Desert.

About the University of Hertfordshire

The University of Hertfordshire is one of the fastest growing universities in the UK, and currently the leading business-facing university around. With a key focus on developing creative learning, teaching and research, it is no wonder that many companies and enterprises engage with the University of Hertfordshire to add value and growth to their various business projects.  The interaction of High 5 Ltd with the Performance Testing Consultancy within the Division of Sport, Health and Exercise is just one example where applied research has been employed to develop new sports nutrition products that are changing the way athletes train and perform.

For more information visit

Get 33% off

Sign up to our newsletter and receive 33% off your first order
Hints, tips, special offers and more

You have the right to withdraw your consent and object to our use of your details for marketing purposes at any time. If you wish to amend your marketing choices in the future, please email To know more about how we use your data, please see our Privacy Notice.

Your Basket

You're £35.00 away from free UK shipping!




Looks like you haven't added anything to your basket yet?

Continue shopping

Product added to cart!