The microalgae advantage: physiological and functional effects of supplementation on exercise performance

Research into the efficacy of microalgae (spirulina and chlorella) supplementation for exercise performance has shown promising results associated with the possible antioxidant capabilities microalgae may possess. However, given some of the fundamental flaws with analysis methodologies in human physiology, the antioxidant focused research has consequently been equivocal. It therefore remains unclear which modality, exercise intensity, dose strategy, and mechanism may be causing the efficacious exercise performance results. The purpose of this thesis was to to systematically focus on one supplementation strategy (6 g/day for 3-weeks), and to examine the possible alternative mechanisms and effects microalgae supplementation may have on a variety of exercise intensities/modalities/environments.

Throughout this thesis, all studies employed a double-blinded, randomised, counter balanced, crossover design where participants ingested 6 g/day of placebo and spirulina (study one and three) or chlorella (study two and four) for 3-weeks, with a 2-week washout period between conditions.

The first two studies attempted to address the paucity of research examining the efficacy of microalgae supplementation during the multiple intensities’ cyclists experience during training and competition. Participants completed a 1-hour submaximal endurance test at 55% external power output max and a 16.1km time trial (day 1), followed by a lactate threshold test and a repeated sprint performance test (RSPT) (day 2). In comparison to placebo, both spirulina and chlorella supplementation resulted in lower lactate and heart rate during submaximal exercise tests, increased peak and mean power during RSPT’s, and an increase in haemoglobin (P<0.05). No differences were observed during the 16.1km time trial and lactate threshold test (P>0.05).

The final two studies branched off into different investigative avenues which were tailored specifically towards the possible ergogenic mechanisms/intensities speculated to be efficacious from study one and two. Study three sought to understand whether improvements in haemoglobin (and other blood morphological parameters) following spirulina supplementation were repeatable using an automated analyser, and if so whether this may benefit a cyclist’s lactate threshold performance at simulated moderate altitude (2,500m). Following spirulina supplementation, heart rate at the lactate threshold was lower in comparison to placebo (P<0.05). No other performance variables (power output, VO2, RPE, RER) were significant (P>0.05). Red cell distribution width significantly increased and platelecrit significantly decreased following spirulina supplementation in comparison to placebo (P<0.05). In contrast to previous literature, no improvements were observed in all other blood morphological parameters (P>0.05).

The final study examined and compared the influence of chlorella supplementation during 2km rowing time trials, as this intensity and modality were yet to be investigated, whilst also investigating the influence on blood pressure/blood lipids. No significant differences (P>0.05) were observed between all performance variables (heart rate, power, lactate, time to complete, strokes per minute) and blood lipids. A small but significant (P<0.05) reduction in systolic blood pressure was observed following chlorella supplementation.

To conclude, the results from this thesis indicate that the ingestion of spirulina or chlorella (6 g/day for 3-weeks) operates as an effective ergogenic aid in trained cyclists however the results are not consistent when manipulating the modality (rowing) and environment (altitude). Therefore, at this time, whilst cyclists should strongly consider supplementation, it remains unclear whether supplementing microalgae may be appropriate for all athletes in their chosen sport.