Fourteen-Days Spirulina Supplementation Increases Hemoglobin, but Does Not Provide Ergogenic Benefit in Recreationally Active Cyclists: A Double-Blinded Randomized Crossover Trial

Abstract

Spirulina supplementation has been reported to increase hemoglobin concentration as well as a variety of cardiorespiratory and lactate-based performance parameters during maximal and submaximal states of exercise. This study investigates the efficacy of supplementing a 6 g/day dosage of spirulina for 14-days in recreationally active individuals, analyzing cardiorespiratory parameters during maximal and submaximal cycling as well as the potential mechanistic role of hemoglobin augmentation. 17 recreationally active individuals (Male = 14, Female = 3, Age 23 ± 5 years, V̇O_2max 43.3 ± 8.6 ml/min·kg) ingested 6 g/day of spirulina or placebo for 14-days in a double-blinded randomized crossover study, with a 14-day washout period between trials. Participants completed a 20-min submaximal cycle at 40% maximal power output (WR_max), followed by a V̇O_2max test. Hemoglobin (g/L), WR_max (watts), time to fatigue (seconds), heart rate (bpm), oxygen uptake (ml/min·kg), RER and blood lactate response (mmol/L) were measured and compared between conditions. Cardiorespiratory variables were recorded at 5-min intervals and lactate was measured at 10-min intervals during the submaximal exercise. There was a significant 3.4% increase in hemoglobin concentration after spirulina supplementation in comparison to placebo (150.4 ± 9.5 g/L Vs 145.6 ± 9.4 g/L, p = 0.047). No significant differences existed between either condition in both testing protocols for V̇O_2max, WR_max, time to fatigue, heart rate, oxygen uptake, RER and blood lactate response (p > 0.05). 14-days of spirulina supplementation significantly improved hemoglobin concentration but did not lead to any considerable ergogenic improvements during maximal or submaximal exercise at a 6 g/day dosage in recreationally active individuals whilst cycling.

Keywords:

• Algae
• cycling
• hemoglobin
• spirulina

Authors’ contributions

The study was designed by Y. Ali, R. Aubeeluck and T. Gurney; data were collected by Y. Ali and R. Aubeeluck; data analysis and interpretation was undertaken by Y. Ali and R. Aubeeluck; manuscript preparation was undertaken by Y. Ali, R. Aubeeluck and T. Gurney. All authors approved the final version of the paper.

Disclosure statement

No potential conflict of interest was reported by the authors.

Ethical approval

The authors declare that the results of the study are presented clearly, honestly, and without fabrication, falsification or inappropriate data manipulation in any way to intentionally portray anything but those outcomes that were observed. The Ethics Committee at University College London approved the study (21745/001) in accordance to the Helsinki Declaration. All participants completed informed consent before participating in the study.

Data availability statement

Data generated or analyzed during this study are available from the corresponding author upon request.

Additional information

Funding

The author(s) reported there is no funding associated with the work featured in this article.

Notes on contributors

Yunus Ali

Yunus Ali is a fifth year medical student at University College London and has completed a BSc in Medical Sciences with Sports and Exercise Medicine (Hons). His research interests include sport, supplementation, and exercise.

Rama Aubeeluck

Rama Aubeeluck is a fifth year medical student at University College London and has completed a BSc in Medical Sciences with Sports and Exercise Medicine (Hons). His research interests include sports and exercise within the context of healthcare and medicine.

Tom Gurney

Tom Gurney is in the final stages of his PhD at Kingston University and is a lecturer at University College London. His research interests are supplementation for exercise and health.