Chlorella-induced Increase In Cardiac Function Further Enhances Aerobic Capacity By Short-term High Intensity Intermittent Training

High intensity intermittent training (HIIT) enhances aerobic capacity. Our study using rodent animal model has demonstrated that chronic chlorella intake combined with HIIT further accelerated high intensity intermittent exercise performance as compared with HIIT alone. However, in the human study, it is unclear whether chronic chlorella intake combined with HIIT has more pronounced effect on aerobic capacity. PURPOSE: To clarify the effects of combination of chlorella intake and short-term HIIT on aerobic capacity. METHODS: [Study 1] Twelve healthy young male subjects completed 3-week of exhaustive HIIT, consisting of 6-7 bouts of 20-second cycling on a leg ergometer at an intensity of 170% maximal oxygen uptake (VO2max) with a 10-second rest between each bout, 3 days/week. They orally took chlorella or placebo (15 tablets) after the breakfast and dinner between the 3-week in a double-blind, randomized, crossover design with a 4-week washout period. [Study 2] To clearly a mechanism of the effect of chlorella intake on aerobic capacity, we examined cardiac output [CO], which is a determinant of VO2max. Six healthy young male subjects orally took chlorella or placebo between the 4-week in a double-blind, randomized, placebo-controlled, crossover design with a 4-week washout period. We measured the VO2max and cardiac function (stroke volume [SV], heart rate [HR], CO) at the measurement of VO2max. RESULTS: [Study 1] After each HIIT, VO2max was significantly increased in both chlorella and placebo groups (P < 0.05). However, the changes in VO2max were significantly higher in chlorella group than placebo group (P < 0.05). [Study 2] The changes in SV and CO with elevated ejection fraction during exercise at exercise intensity of VO2max were significantly higher in chlorella group compared to placebo group (P < 0.05, respectively), but HRmax and left ventricular hypertrophy did not change. Additionally, the changes in VO2max were positively correlated with the changes in SV (P < 0.05, r = 0.903) and CO (P < 0.05, r = 0.835) in chlorella group. CONCLUSION: These results suggest that the chlorella intake combined with short-term HIIT may further enhance aerobic capacity via chlorella intake-induced increase in cardiac function. Supported by Grants in Sun Chlorella Corp.