Bitter Orange (Citrus aurantium L.) Intake Before Submaximal Aerobic Exercise Is Safe for Cardiovascular and Autonomic Systems in Healthy Males: A Randomized Trial

Abstract

BackgroundThere are still no studies of the cardiovascular safety of the isolated use of Citrus aurantium in aerobic submaximal exercise.ObjectiveTo evaluate the effect of C. aurantium supplementation on the recovery of cardiorespiratory and autonomic parameters following a session of submaximal aerobic exercise.MethodsTwelve healthy male adults achieved a crossover, randomized, double-blind, and placebo-controlled trial. C. aurantium (600 mg, p-synephrine at 30% amount [180 mg]) or placebo (600 mg of starch) were ingested 90 min before evaluation in randomized days. We evaluated systolic blood pressure (SBP), diastolic blood pressure (DBP), pulse pressure (PP), mean arterial pressure (MAP), heart rate (HR) and, HR variability indexes at Rest and during 60 min of recovery from exercise.ResultsCitrus aurantium ingestion accelerated the reduction in SBP after exercise, anticipated the return of vagal modulation of the heart after exercise via the HF (ms2), pNN50 (%), and 2 UV% indices. Moreover, rushed the output of sympathetic modulation after exercise via the 0V% index. No unfavorable cardiovascular effects were achieved for HR, DBP, PP, and MAP parameters.ConclusionsCitrus aurantium was shown to be safe for the cardiovascular and autonomic systems alongside submaximal aerobic exercise in healthy males.

The Safety and Efficacy of Citrus aurantium (Bitter Orange) Extracts and p-Synephrine: A Systematic Review and Meta-Analysis

“…The 18 trials included were double-blinded, prospective, parallel or crossover, within-subjects or counterbalanced studies ( Table S2 ). Seven trials were crossover [ 43 , 44 , 45 , 46 , 47 , 48 , 49 ]; five had parallel design [ 22 , 50 , 51 , 52 , 53 ]; four had within-subjects [ 54 , 55 ] or other [ 56 , 57 ] designs; and two were performed in a counterbalanced manner [ 58 , 59 ].…”

“…Fourteen trials assessed the acute effects of synephrine [ 43 , 44 , 45 , 46 , 47 , 48 , 49 , 53 , 54 , 55 , 56 , 57 , 58 , 59 ]. In four trials, the effect of a longer treatment duration (a range of 4–8 weeks) was assessed [ 22 , 50 , 51 , 52 ].…”

“…The inclusion criteria of the trials varied from trial to trial. Eight trials only included physically active subjects [ 22 , 45 , 49 , 50 , 52 , 54 , 56 , 59 ]. In eight trials, healthy, normotensive but not resistance-trained subjects were involved [ 43 , 44 , 46 , 48 , 51 , 53 , 55 , 57 ].…”

“…In several trials, other interventions were also studied, but these study arms were not included in our analysis [ 45 , 50 , 51 , 53 , 54 , 55 , 56 ]. Nine trials involved exercise training [ 22 , 45 , 49 , 50 , 52 , 56 , 57 , 58 , 59 ]. It is important to emphasize that while comparing weight loss and body compositions from the analyzed three articles [ 22 , 50 , 52 ], all of these trials included exercise intervention, and two involved dietary restrictions [ 22 , 52 ].…”

“…However, the subgroup of regular high caffeine users (>300 mg) was excluded from our final meta-analysis to make the analyzed groups more homogenous. In seven trials, participants were requested to limit caffeine consumption [ 22 , 49 , 51 , 52 , 56 , 57 , 59 ].…”