Research pick: Rooibos and exercise - "The efficacy of rooibos Aspalathus linearis as an ergogenic aid during exercise"

Can drinking tea made from leaves of the “rooibos” plant, Aspalathus linearis, improve physical performance during exercise? That was the question a team from South Africa set out to answer. They report their findings in the International Journal of Human Factors and Ergonomics.

Simeon Davies of the Department of Sport Management, Cape Peninsula University of Technology, in Cape Town, and colleagues there and in the university’s Oxidative Stress Research Centre explain how rooibos herbal tea, often referred to as bush tea in Southern Africa o redbush tea in the United Kingdom, has become a popular product, although well known in South Africa for generations. It has a taste not dissimilar to hibiscus tea but sometimes with what is often referred to as an earthy flavour. However, taste aside, there is always interest in the putative physiological activity of any traditional drink given the wide range of natural products, such as alkaloids and antioxidants, that might be present in such a drink.

Such a drink might counteract the formation of free radicals and other oxidizing species that form naturally in the body through metabolism and especially during exercise. Free radicals have their uses in the body’s defences but are largely problematic causing damage at the cellular and molecular level. During exercise, this might lead to pain and inflammation as well as premature muscle fatigue. So, might a drink containing relatively high levels of antioxidants be useful in the sport and exercise context?

Tests with 32 male volunteers and a fatiguing arm exercise test to exhaustion showed that the group drinking rooibos prior to the tests performed the exercise for longer without premature fatigue. This was compared to the group of volunteers who drank a “placebo tea”, a similar-tasting infusion with none of the antioxidants present in rooibos.

“It is tentatively suggested that a worker/person engaged in tasks of a repetitive nature requiring forceful actions may benefit from supplementing his/her diet with rooibos, a recognised antioxidant, because it may reduce the precursors to cellular oxidative damage, namely reactive oxygen species and reactive nitrogen species,” the team says. They add that there was prior evidence that acute “dosing” with rooibos might be more beneficial than long-term use of this herbal tea.

Davies, S.E.H., Marnewick, J.L., West, S., Taliep, M.S., Rautenbach, F. and Gamieldien, R. (2019) ‘The efficacy of rooibos Aspalathus linearis as an ergogenic aid during exercise’, Int. J. Human Factors and Ergonomics, Vol. 6, No. 1, pp.88-102.