title: Coconut Water Does Not Improve Markers of Hydration During Sub-maximal Exercise and Performance in a Subsequent Time Trial Compared with Water Alone.
abstract: The purpose of this study was to compare markers of hydration during submaximal exercise and subsequent time trial performance when consuming water (PW) or coconut water (CW). There was also a secondary aim to assess the palatability of CW during exercise and voluntary intake during intense exercise. 10 males (age 27.9 ± 4.9 years, body mass 78.1 ± 10.1kg, average max minute power 300.2 ± 28.2W) completed 60-min of submaximal cycling followed by a 10-km time trial on two occasions. During these trials participants consumed either PW or CW in a randomized manner, drinking a 250 ml of the assigned drink between 10-15 min, 25-30 min and 40-45 min, and then drinking ad libitum from 55-min until the end of the time trial. Body mass and urine osmolality were recorded preexercise and then after 30-min, 60-min, and post time trial. Blood glucose, lactate, heart rate, rate of perceived exertion (RPE; 6-20) and ratings of thirst, sweetness, nausea, fullness and stomach upset (1 =very low/none, 5= very high) were recorded during each drink period. CW did not significantly improve time trial performance compared with PW (971.4 ± 50.5 and 966.6 ± 44.8 s respectively; p = .698) and there was also no significant differences between trials for any of the physiological variables measured. However there were subjective differences between the beverages for taste, resulting in a significantly reduced volume of voluntary intake in the CW trial (115 ± 95.41 ml and 208.7 ± 86.22 ml; p < .001).
authors: Daniel J
authors: DJ
authors: Peart
authors: Andy
authors: A
authors: Hensby
authors: Matthew P
authors: MP
authors: Shaw
mesh_terms: D000328:Adult; D054874:Athletic Performance; D001642:Bicycling; D001786:Blood Glucose / Q000032:analysis; D003059:Cocos; D015444:Exercise / Q000502:physiology*; D005080:Exercise Test; D006339:Heart Rate; D006801:Humans; D019344:Lactic Acid / Q000097:blood; D008297:Male; D064133:Sports Nutritional Physiological Phenomena; D013649:Taste; D013894:Thirst; D014867:Water / Q000008:administration & dosage*; D055815:Young Adult
chemical_list: D001786:Blood Glucose; D014867:Water; D019344:Lactic Acid
keywords: glucose; palatability; perceived exertion; urine osmolality