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.

The Efficacy of Chlorella Supplementation on Multiple Indices of Cycling Performance.

This study investigated the effects of chlorella supplementation on submaximal endurance, time trial performance, lactate threshold, and power indices during a repeated sprint performance test by fourteen male trained cyclists. Participants ingested 6 g/day of chlorella or placebo for 21-days in a double-blinded randomized counter-balanced cross-over design, with a fourteen-day washout period between trials. Each completed a 2-day testing period comprising a 1-hour submaximal endurance test at 55% external power output max and a 16.1 km time trial (Day-1), followed by a lactate threshold (Dmax) and repeated sprint performance tests (3 X 20 s sprints interspersed by 4-mins) (Day-2). Heart rate (b.min-1), RER, V̇O2 (ml·kg-1·min-1), lactate and glucose (mmol/L), time (secs), power output (W/kg), and hemoglobin (g/L) were compared across conditions. Following chlorella supplementation (chlorella vs. placebo for each measurement) average lactate and heart rate were significantly lower (p < 0.05) during submaximal endurance tests (1.68 ± 0.50 mmol/L vs. 1.91 ± 0.65 mmol/L & 138 ± 11b.min-1 vs. 144 ± 10b.min-1), average power and peak power (W/kg) were significantly higher during repeated sprint bouts (9.5 ± 0.7 W/kg vs. 9.0 ± 0.7 W/kg & 12.0 ± 1.2 W/kg vs. 11.4 ± 1.4 W/kg), hemoglobin significantly increased (149.1 ± 10.3 g/L) in comparison to placebo (143.4 ± 8.7 g/L) (p = 0.05). No differences existed between conditions for all oxygen consumption values, 16.1 km time trial measures and lactate threshold tests (p > 0.05). In conclusion, chlorella may pose as an additional supplement for cyclists to consider, particularly for those cyclists who want to improve their sprinting.

Comment on Hack et al. Effect of Guarana (Paullinia cupana) on Cognitive Performance: A Systematic Review and Meta-Analysis. Nutrients 2023, 15, 434.

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

Cognitive effects of guarana supplementation with maximal intensity cycling.

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 one of three supplements, on three different days: guarana (125 mg/kg), caffeine (5 mg/kg) or placebo (65 mg/kg protein powder). After 30 min 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, and cognitive tests were then immediately repeated. Guarana supplementation decreased CRT before exercise (407 (sd 45) ms) in comparison with placebo (421 (sd 46) ms, P = 0·030) but not caffeine (417 (sd 42) ms). SRT after exercise decreased following guarana supplementation (306 (sd 28) ms) in comparison with placebo (323 (sd 32) ms, P = 0·003) but not caffeine (315 (sd 32) ms). Intra-individual variability on CRT significantly improved from before (111·4 (sd 60·5) ms) to after exercise (81·85 (sd 43·1) ms) following guarana supplementation, and no differences were observed for caffeine and placebo (P > 0·05). Alertness scores significantly improved following guarana supplementation (63·3 (sd 13·8)) in comparison with placebo (57·4 (sd 13·4), P = 0·014) but not caffeine (61·2 (sd 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).

Spirulina supplementation improves oxygen uptake in arm cycling exercise.

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.