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

Physiological effects of spirulina supplementation during lactate threshold exercise at simulated altitude (2,500 m): a randomized controlled trial

BACKGROUND

Existing literature indicates that spirulina supplementation can improve a variety of blood morphological parameters (such as hemoglobin) in healthy and clinical populations. Given the importance of hemoglobin for endurance exercise, particularly at altitude, this study aimed to investigate whether spirulina supplementation can improve blood morphological parameters in healthy cyclists and positively influence physiological variables when completing a lactate threshold test at simulated moderate altitude (2,500 m).

METHODS

Twenty (18 male; 2 female) healthy participants (Mean  ±  SD; Age 37   ±   9 years, Stature 181   ±   6 cm, Mass 81   ±   9 kg, V ˙ O2max 51.8   ±   7.8 ml·kg-1·min-1) ingested 6 g/day of spirulina or placebo for 3-weeks in a double-blinded randomized counter-balanced cross-over design, then completed a lactate threshold test at simulated moderate altitude, with a 14-day washout period between trials.

RESULTS

Following spirulina supplementation, heart rate at the lactate threshold was significantly lower in comparison to placebo supplementation (spirulina = 152   ±   11 b.min -1 vs. placebo = 155   ±   12 b.min -1, p < 0.05). No other physiological variables (Watts, RER, RPE, VO2) were significantly different (p > 0.05) at the calculated threshold, or during the first four lower stages. Red Cell Distribution Width significantly increased following spirulina supplementation in comparison to placebo (spirulina = 13.3   ±   0.9 % vs. placebo = 12.5   ±   0.7 %, p < 0.05). Plateletcrit significantly decreased following spirulina supplementation (spirulina = 0.288   ±   0.032 vs. placebo = 0.293   ±   0.050, p < 0.05). No other blood morphological parameters changed (p > 0.05).

CONCLUSION

In conclusion, three weeks of spirulina supplementation at 6 g/day reduced heart rate during a lactate threshold test at a simulated moderate altitude (2,500 m), but did not produce additional physiological or hematological benefits.

Chlorella Supplementation Reduces Blood Lactate Concentration and Increases O2 Pulse during Submaximal and Maximal Cycling in Young Healthy Adults

Chlorella supplementation is reported to improve V˙O2max following extended supplementation periods (~3 weeks). However, there is little research on its impact over submaximal exercise intensities and following shorter supplementation regimens. This study aimed to investigate the efficacy of 6 g/day 2-day chlorella supplementation on exercise performance in healthy young adults. Twenty young healthy adults (Males = 16, Females = 4) (Age 22 ± 6 years, V˙O2max 42.7 ± 9.6 mL/(kg·min)) were recruited for this double-blinded, randomised cross-over study. Participants ingested 6 g/day of chlorella or a placebo for 2 days, with a one-week washout period between trials. Exercise testing consisted of a 20 min submaximal cycle at 40% of their work rate max (WRmax) (watts), followed by an incremental V˙O2max test. Lactate (mmol/L), heart rate (b/min), oxygen consumption (mL/(kg·min)), O2 pulse (mL/beat), respiratory exchange ratio (RER), and WRmax were compared across conditions. Following chlorella supplementation, blood lactate levels were significantly lower (p < 0.05) during submaximal exercise (3.05 ± 0.92 mmol/L vs. 2.67 ± 0.79 mmol/L) and following V˙O2max tests (12.79 ± 2.61 mmol/L vs. 11.56 ± 3.43 mmol/L). The O2 pulse was significantly higher (p < 0.05) following chlorella supplementation during submaximal (12.6 ± 3.5 mL/beat vs. 13.1 ± 3.5 mL/beat) and maximal exercise intensity (16.7 ± 4.6 mL/beat vs. 17.2 ± 4.5 mL/beat). No differences existed between conditions for oxygen consumption, RER, V˙O2max, or WRmax. A total of 2 days of 6 g/day chlorella supplementation appears to lower the blood lactate response and increase O2 pulse during both submaximal and maximal intensity exercise but did not lead to any improvements in V˙O2max.