Oxidation of maltose and trehalose during prolonged moderate-intensity exercise.
OBJECTIVE
The aim of the present study was to compare the effects of trehalose (TRE) and maltose (MAL) ingestion on exogenous carbohydrate oxidation rates and blood metabolite responses during prolonged moderate-intensity cycling exercise.


METHODS
Nine trained subjects performed three randomly assigned bouts of exercise separated by at least 1 wk. Each trial consisted of 150 min of cycling at 55% of maximal power output (Wmax) while ingesting a solution providing either 1.1 g x min(-1) TRE, 1.1 g x min(-1) MAL, or water (WAT).


RESULTS
Total carbohydrate oxidation rates were significantly higher (P < 0.05) in both the MAL (2.09 +/- 0.18 g x min(-1)) and TRE (1.92 +/- 0.32 g x min(-1)) trials compared with the WAT trial (1.62 +/- 0.28 g x min(-1)). Peak exogenous carbohydrate oxidation was significantly higher in the MAL trial compared with the TRE trial (1.01 +/- 0.24 and 0.73 +/- 0.22 g x min(-1), respectively, P < 0.05). The MAL trial resulted in significantly reduced endogenous carbohydrate oxidation rates compared with the WAT trial (1.20 +/- 0.25 and 1.62 +/- 0.28 g x min(-1), respectively, P < 0.05). When compared with the WAT trial, total fat oxidation for the same period was significantly reduced in both carbohydrate trials (0.91 +/- 0.19, 0.68 +/- 0.19, and 0.79 +/- 0.19 g x min(-1) for WAT, MAL, and TRE, respectively, P < 0.05) and tended to be lower in MAL compared with TRE (P < 0.06).


CONCLUSIONS
Both solutions maintained high plasma glucose concentrations. MAL had a "sparing" effect on endogenous carbohydrate stores. The reduced exogenous carbohydrate oxidation rate of TRE compared to MAL is probably due to a reduced enzymatic hydrolysis rate within the small intestine, causing a slower availability.
Venables
Michelle C
MC
Human Performance Laboratory, School of Sport and Exercise Sciences, University of Birmingham, Edgbaston, United Kingdom.
Brouns
Fred
F
Jeukendrup
Asker E
AE
D000328:Adult; D050260:Carbohydrate Metabolism / Q000187:drug effects; D015444:Exercise / Q000502:physiology*; D006801:Humans; D008297:Male; D008320:Maltose / Q000008:administration & dosage* / Q000378:metabolism; D010088:Oxidoreductases / Q000378:metabolism*; D005082:Physical Exertion / Q000502:physiology*; D013549:Sweetening Agents / Q000008:administration & dosage* / Q000378:metabolism; D014199:Trehalose / Q000008:administration & dosage* / Q000378:metabolism; D055815:Young Adult
D013549:Sweetening Agents; D008320:Maltose; D014199:Trehalose; D010088:Oxidoreductases