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Dose–Response Effects of p ‐Synephrine on Fat Oxidation Rate During Exercise of Increasing Intensity
Author(s) -
GutiérrezHellín Jorge,
Del Coso Juan
Publication year - 2018
Publication title -
phytotherapy research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.019
H-Index - 129
eISSN - 1099-1573
pISSN - 0951-418X
DOI - 10.1002/ptr.5937
Subject(s) - placebo , ingestion , heart rate , exercise intensity , intensity (physics) , medicine , endocrinology , chemistry , physical exercise , zoology , cycle ergometer , blood pressure , biology , physics , alternative medicine , pathology , quantum mechanics
The aim of this investigation was to determine the effects different doses of p ‐synephrine on maximal fat oxidation during exercise. Seventeen healthy subjects volunteered to participate in a double‐blind and randomised experimental design composed of four identical experimental trials. On four trials separated by 72 h, participants ingested a placebo or 1, 2 or 3 mg/kg of p ‐synephrine. After resting for 60 min to allow substance absorption, participants performed an exercise test of increasing intensity on a cycle ergometer while gas exchange was measured continuously. None of the doses of p ‐synephrine affected energy expenditure or heart rates during the test. The highest rate of fat oxidation with the placebo (0.35 ± 0.05 g/min) was reached at 38.0 ± 1.9% of VO 2max . The ingestion of 1 mg/kg increased maximal fat oxidation to 0.47 ± 0.11 g/min ( p = 0.01) but did not change the intensity at which it was obtained (42.0 ± 9.4% of VO 2max ). The ingestion of 2 and 3 mg/kg of p ‐synephrine increased maximal fat oxidation to 0.55 ± 0.14 g/min ( p < 0.01), although only 3 mg/kg slightly changed the intensity at which it was obtained (43.0 ± 9.5% of VO 2max , p < 0.01). In conclusion, although all p ‐synephrine increased the maximal rate of fat oxidation during exercise, the highest effects were found with 2 and 3 mg/kg. Copyright © 2017 John Wiley & Sons, Ltd.