Purpose Spirulina has previously been reported to improve high-intensity exercise performance and hemoglobin. However, spirulina’s effect on arm cycling exercise has yet to be investigated. The purpose of this study was to investigate the responses of spirulina supplementation on hemoglobin and on oxygen uptake, RER and HR during seated arm cycling exercise. Methods In a double-blinded randomized crossover design, eleven males untrained in arm cycling ingested 6 g/day of spirulina or placebo for seven days. Seated on the Arm Crank Ergometer, each participant performed a baseline V̇O2max test, and then after supplementation, 2 × 30-min submaximal exercise bouts corresponding to 55% of their V̇O2max, followed by an incremental test to fatigue. A seven-day wash-out period was required between conditions. Oxygen uptake, RER and HR were measured continuously during exercise and hemoglobin measured prior to exercise after both conditions. Results Spirulina significantly (p < 0.05) increased Hb in comparison to Placebo (144.1 g/l ± 10.5 Vs 154.5 g/l ± 6.9). After spirulina supplementation, during the 30-min exercise bouts, oxygen uptake and HR were significantly lower (2170 ml/min ± 173 Vs 2311 ml/min ± 189 and 154 bpm ± 14 Vs 149 bpm ± 17), RER was not significantly different. In comparison to placebo, Spirulina significantly increased oxygen uptake at time of fatigue (34.10 ml/min/kg ± 6.03 Vs 37.37 ml/min/kg ± 5.98). Time taken to fatigue was not different. Conclusion Spirulina supplementation significantly reduces oxygen uptake and HR during arm cycling submaximal exercise, allowing for an increased oxygen uptake during an incremental test to fatigue.

Spirulina supplementation is reported to improve time to exhaustion and V̇O2max. However, there is limited information on its influence over the multiple intensities cyclists experience during training and competition. Fifteen trained males (Age 40 ± 8 years, V̇O2max 51.14 ± 6.43 ml/min/kg) ingested 6g/day of spirulina or placebo for twenty-one days in a double-blinded randomized cross over design, with a fourteen-day washout period between trials. 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 repeated sprint performance tests (RSPTs) (day 2). Heart rate (bpm), Respiratory Exchange Ratio, oxygen consumption (ml/min/kg), lactate and glucose (mmol/L), time (secs), power output (Watts), and hemoglobin (g/L) were compared across conditions. Following spirulina supplementation, lactate and heart rate were significantly lower (P<0.05) during submaximal endurance tests (2.05 ± 0.80mmol/L Vs 2.39 ± 0.89mmol/L & 139 ± 11bpm Vs 144 ± 12bpm), hemoglobin was significantly higher (152.6 ± 9.0 g/L) than placebo (143.2 ± 8.5 g/L), and peak and average power were significantly higher during RSPTs (968 ± 177Watts Vs 929 ± 149Watts & 770 ± 117Watts Vs 738 ± 86Watts). No differences existed between conditions for all oxygen consumption values, 16.1km time trial measures and lactate threshold tests (P>0.05). Spirulina supplementation reduces homeostatic disturbances during submaximal exercise and augments power output during RSPTs. Novelty bullets: • Spirulina supplementation lowers heart rate and blood lactate during ≈1-hour submaximal cycling. • Spirulina supplementation elicits significant augmentations in hemoglobin and power outputs during RSPTs.

Nutritional clinical trials have reported algae such as spirulina and chlorella to have the capability to improve cardiovascular risk factors, anemia, immune function, and arterial stiffness. With positive results being reported in clinical trials, researchers are investigating the potential for algae as an ergogenic aid for athletes. Initial studies found spirulina and chlorella supplementation to increase peak oxygen uptake and time to exhaustion, with the mechanistic focus on the antioxidant capabilities of both algae. However, a number of oxidative stress biomarkers reported in these studies are now considered to lack robustness and have consequently provided equivocal results. Considering the nutrient complexity and density of these commonly found edible algae, there is a need for research to widen the scope of investigation. Most recently algae supplementation has demonstrated ergogenic potential during submaximal and repeated sprint cycling, yet a confirmed primary mechanism behind these improvements is still unclear. In this paper we discuss current algae supplementation studies and purported effects on performance, critically examine the antioxidant and ergogenic differing perspectives, and outline future directions.

The aim of this study was to investigate the effects of guarana supplementation on cognitive performance before and after a bout of maximal intensity cycling, and to compare this to an equivalent caffeine dose. Twenty-five participants completed the randomised double-blind crossover trial by performing cognitive tests with 1 of 3 supplements, on 3 different days: guarana (125 mg/kg), caffeine (5 mg/kg) or placebo (65 mg/kg protein powder). After 30-minutes of rest, participants performed simple (SRT) and choice reaction time (CRT) tests, an immediate word recall test and Bond-Lader mood scale. This was followed by a cycling V̇O2max test, cognitive tests were then immediately repeated. Guarana supplementation decreased CRT before exercise (407 ± 45ms) in comparison to placebo (421 ± 46ms, P=.030) but not caffeine (417 ± 42ms). SRT after exercise decreased following guarana supplementation (306 ± 28ms) in comparison to placebo (323 ± 32ms, P=.003) but not caffeine (315 ± 32ms). Intraindividual variability on CRT significantly improved from before (111.4 ± 60.5ms) to after exercise (81.85 ± 43.1ms) following guarana supplementation, no differences were observed for caffeine and placebo (P>.05). Alertness scores significantly improved following guarana supplementation (63.3 ± 13.8) in comparison to placebo (57.4 ± 13.4, P=.014) but not caffeine (61.2 ± 12.8). There were no changes to V̇O2max, immediate word recall or any other Bond-Lader mood scales. Guarana supplementation appears to impact several parameters of cognition. These results support the use of guarana supplementation to possibly maintain speed of attention immediately following a maximal intensity exercise test (V̇O2max).

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We have read the recent systematic review and meta-analysis by Hack et al. [...]

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