PURPOSE: To establish whether sensory factors associated with cold beverage ingestion exert an ergogenic effect on endurance performance independent of thermoregulatory and/or cardiovascular factors. METHODS: Ten males performed three trials involving 90min steady state cycling (SS) (62% VO2max) in the heat (32.1±0.9°C, 40±2.4% relative humidity) followed by a 4kJ/kg body mass time trial (TT). During SS, participants consumed an identical volume (260±38g) of sports beverage (7.4% carbohydrate) every 15min as either ice slushy (-1°C, ICE), thermoneutral liquid (37°C, CON) or thermoneutral liquid consumption with expectorated ice slushy mouthwash (WASH). RESULTS: Rectal temperature, hydration status, heart rate and skin blood flow were not different between trials. Gastrointestinal (pill) temperature was lower in ICE (35.6±2.7°C) versus CON (37.4±0.7°C, p=0.05). Heat storage tended to be lower with ICE during SS (14.7±8.4W.m-2, p=0.08) and higher during TT (68.9±38.6W.m-2, p=0.03) compared with CON (22.1±6.6 and 31.4±27.6W.m-2). ICE tended to lower rating of perceived exertion (RPE, 12.9±0.6, p=0.05) and improved thermal comfort (TC, 4.5±0.2p=0.01) vs. CON (13.8±1.0 and 5.2±0.2 respectively). WASH RPE (13.0±0.8) and TC (4.8±0.2) tended to be lower vs. CON (p=0.07 and p=0.09 respectively). ICE improved performance (18:28±1:03) compared to CON (20:24±1:46) but not WASH (19:45±1:43). CONCLUSION: Improved performance with ICE ingestion likely resulted from creation of a gastrointestinal heat sink reducing SS heat storage. Although the benefits of cold beverage consumption are more potent when there is ingestion, improved RPE, TC, and meaningful performance improvement with WASH, supports an independent sensory effect of presenting a cold stimulus to the mouth.

http://www.ncbi.nlm.nih.gov/pubmed/23535809