Negligible Effects of Nutraceuticals from Beetroot Extract on Cardiovascular and Autonomic Recovery Response following Submaximal Aerobic Exercise in Physically Active Healthy Males: A Randomized Trial.

BACKGROUND: There is little evidence that nutraceuticals from beetroot extract are beneficial with regards to recovery of the cardiovascular parameters and the autonomic nervous system (ANS) after submaximal aerobic exercise, though this formulation is employed widely for this purpose. OBJECTIVE: To study the effects of beetroot extract supplementation on the recovery of cardiorespiratory and autonomic parameters after a session of submaximal aerobic exercise. METHODS: Sixteen healthy male adults commenced a cross-over, randomized, double-blind and placebo-controlled trial. Beetroot extract (600 mg) or placebo (600 mg) were ingested 120 min prior to evaluation on randomized days. We assessed systolic blood pressure (SBP), diastolic blood pressure (DBP), pulse pressure (PP), mean arterial pressure (MAP), heart rate (HR) and HR variability (HRV) indexes at Rest and during 60 min of recovery from submaximal aerobic exercise. RESULTS: Beetroot extract ingestion slightly accelerated HR, SBP, DBP and MAP reduction following exercise associated to the placebo protocol (vs. rest). Yet no group effect (p = 0.99) was identified between the beetroot and placebo protocols on HR mean, in addition to interaction (group vs. time) (p = 0.60). No group effect was attained between the SBP (p = 0.90), DBP (p = 0.88), MAP (p = 0.73) and PP (p = 0.99) protocols and no significant differences (group vs. time) were observed between the values of SBP (p = 0.75), DBP (p = 0.79), MAP (p = 0.93) and PP (p = 0.63) between placebo and beetroot protocols. Similarly, the reoccurrence of cardiac vagal modulation after exercise via the HF (ms2) was enhanced, but not with regards to the RMSSD index. No group effect (p = 0.99) was identified for the HF (p = 0.90) and RMSSD (p = 0.67) indices. Likewise, we observed no significant differences (group vs. time) amongst the values of HF (p = 0.69) and RMSSD (p = 0.95) between the placebo and beetroot protocols. CONCLUSION: Whilst beetroot extract might assist the recovery of the cardiovascular and autonomic systems following submaximal aerobic exercise in healthy males, these results seem insignificant owing to minor differences between interventions and are weak clinically.

Beetroot (Beta Vulgaris L.) Extract Acutely Improves Heart Rate Variability Recovery Following Strength Exercise: A Randomized, Double-Blind, Placebo-Controlled Crossover Trial-Pilot Study.

OBJECTIVE: We assessed the acute effect of beetroot extract intake on cardiovascular and autonomic recovery subsequent to strength exercise. METHODS: This is a crossover, randomized, double-blind and placebo-controlled trial. We assessed 16 subjects but only 12 healthy male adults completed the two protocols in two randomized days: Beetroot extract (600 mg in capsule) and placebo (600 mg starch in capsule). Beetroot extract or placebo was ingested, the subjects endured 120 minutes seated at rest, followed by a 75% 1RM strength exercise and then remained seated for 60 minutes at rest. Cardiorespiratory parameters, heart rate (HR) variability (HRV) (SDNN, rMSSD, pNN50, SD1, SD2 HF [ms2]) were estimated before, during exercise and during recovery from exercise. RESULTS: ingestion of beetroot extract before exercise: accelerates the recovery of SBP following physical effort; improves HR recovery to baseline resting levels (beetroot protocol: change in ∼62% vs. placebo protocol: change in ∼80%), and intensifies the return of vagal HR control during recovery after exercise. CONCLUSIONS: Beetroot extract acutely improved cardiovascular and autonomic recovery after exercise.