Insights

2023 CANTAB Research Grant: Exploring the role of intermittent exogenous ketosis on physical and mental fatigue during ultra-endurance performance

We caught up with the 2023 CANTAB Research Grant Secondary Award Winner, Louise Engelbrecht, who tells us how the grant will help to provide a better understanding of cognitive function during ultra-endurance performance and the role of ketone ester supplements to retain cognitive function.

I was elated when I got the news about receiving the CANTAB research grant secondary award. The support allows me to collect cognitive function data for both my laboratory and field study without having to secure additional funding for these assessments. Mental fatigue plays a major role in ultra-endurance performance, these assessments will provide a better understanding of cognitive function during ultra-endurance performance and the role of ketone ester supplements to retain cognitive function.

I’m from South Africa and currently busy with a Joint PhD between Stellenbosch University (South Africa) and KU Leuven (Belgium). I completed my Masters degree in 2011 and then worked as a Sport Scientist at Saracens Rugby Club for one season. I returned to South Africa and in 2018 obtained a postgraduate diploma in applied exercise nutrition. I’m currently working as a sport physiologist and exercise nutritionist in the sports physiology laboratory at Stellenbosch University. In my PhD project I will explore the roles of intermittent exogenous ketosis on physical and mental fatigue during ultra-endurance performance.

What is the project about, and why is this important?

Over the last 25 years, there has been an exponential rise in the popularity of ultra-endurance sporting events, especially among recreational athletes¹. These events challenge the human physiological and psychological limits, and they require extreme prolonged physical exertion with minimal recovery and sleep possibilities². Mental fatigue is one of multiple factors that may limit performance during ultra-endurance exercise. Central fatigue contributes towards overall fatigue in events lasting longer than 5 hours, directly impacting force production³. Mental fatigue can negatively affect decision-making and response time during ultra-endurance performance, increasing the risk of injury. Interestingly over the past years ketone ester ingestion can beneficially impact each of these aspects in response to either acute exercise or excessive training^4-6. Therefore, it is our working hypothesis that ketone esters can also improve these aspects during multi-day endurance exercise events and thereby extending the physiological and psychological limits of human endurance. We will conduct two studies, study one will be a laboratory study during which we will simulate an 8-day mountain bike race, while study two will be a field study conducted during the Absa Cape Epic an 8-day mountain bike stage race. 24 subjects will recruit for the laboratory study and pair-matched based on their physiological data, while 10 teams (2 riders per team) will be recruited for the field study. Cognitive assessments will take place at baseline, after day 4 of racing and at the end of the race.

Which CANTAB tests will you use?

Both of these studies have an extensive protocol consisting of questionnaires, physiological measurements and cognitive assessments, while also competing in a race. CANTAB Connect™ battery offers tests which will provide us with a comprehensive cognitive assessment conducted within a short duration of time (approx. 12 minutes). Another benefit of the CANTAB test is that they can be conducted on a tablet which will make field testing easier. We selected three tests which will give us the best information concerning mental fatigue during ultra-endurance performance, including reaction time (RTI), rapid visual information processing (RVP), and spatial working memory (SWM).

Do you have any future studies planned?

While this study will focus on multi-day mountain biking, it will be worthwhile to investigate the effect of ketone ester supplementation on ultra-endurance trail running, especially 100-miler races. Adventure racing is also growing in popularity and an area where the effects of a ketogenic diet on cognitive function may be beneficial and should be investigated.

Further information

If you would like to discuss Louise’s research, please email louise@fuelform.co.za

References

Scheer, V. Participation Trends of Ultra Endurance Events. Sports Med. Arthrosc. Rev. 27, 3–7 (2019).
Costa, R. J. S., Hoffman, M. D. & Stellingwerff, T. Considerations for ultra-endurance activities: part 1- nutrition. Res. Sports Med. 27, 166–181 (2019).
Millet, G. P. & Millet, G. Y. Ultramarathon is an outstanding model for the study of adaptive responses to extreme load and stress. BMC Med. 10, 77 (2012).
Evans, M. & Egan, B. Intermittent Running and Cognitive Performance after Ketone Ester Ingestion. Med. Sci. Sports Exerc. 50, 2330–2338 (2018).
Poffé, C., Ramaekers, M., Thienen, R. V. & Hespel, P. Ketone ester supplementation blunts overreaching symptoms during endurance training overload. J. Physiol. 597, 3009–3027 (2019).
Poffé, C., Robberechts, R., Vanderroost, J., Bogaerts, S. & Hespel, P. Exogenous Ketosis Counteracts The Decline In Cognitive Function During Ultra-running: 333. Med. Sci. Sports Exerc. 54, 77–77 (2022).