Why do team-sport athletes drink fluid in excess when exercising in cool conditions?
This study assessed the potential physiological and perceptual drivers of fluid intake and thirst sensation during intermittent exercise. Ten male rugby players (17 ± 1 years, stature: 179.1 ± 4.2 cm, body mass (BM): 81.9 ± 8.1 kg) participated in six 6-min small-sided games, interspersed with 2 min rest, where fluid intake was ad libitum during rest periods. Pre- and postmeasurements of BM, subjective ratings (thirst, thermal comfort, thermal sensation, mouth dryness), plasma osmolality (POsm), serum sodium concentration (S[Na+]), haematocrit and haemoglobin (to calculate plasma volume change; PV) were taken. Fluid intake was measured during rest periods. BM change was -0.17 ± 0.59% and fluid intake was 0.88 ± 0.38 L. Pre- to post-POsm decreased (-3.1 ± 2.3 mOsm·kg-1; p = 0.002) and S[Na+] remained similar (-0.3 ± 0.7 mmol·L-1, p = 0.193). ΔPV was 5.84 ± 3.65%. Fluid intake displayed a relationship with pre-POsm (r = -0.640, p = 0.046), prethermal comfort (r = 0.651; p = -0.041), ΔS[Na+] (r = 0.816, p = 0.004), and ΔPV (r = 0.740; p = 0.014). ΔThirst sensation displayed a relationship with premouth dryness (r = 0.861, p = 0.006) and Δmouth dryness (r = 0.878, p = 0.004). Yet a weak positive relationship between Δthirst sensation and fluid intake was observed (r = 0.085, p = 0.841). These data observed in an ambient temperature of 13.6 ± 0.9 °C, suggest team-sport athletes drink in excess of fluid homeostasis requirements and thirst sensation in cool conditions; however, this was not influenced by thermal discomfort.
Institute of Sport, Physical Activity and Leisure, G05 Carnegie Hall, Headingley Campus, Leeds Beckett University, Leeds, W. Yorkshire, United Kingdom LS6 3QS.|Institute of Sport, Physical Activity and Leisure, G05 Carnegie Hall, Headingley Campus, Leeds Beckett University, Leeds, W. Yorkshire, United Kingdom LS6 3QS.
Melissa J
MJ
Bargh
Institute of Sport, Physical Activity and Leisure, G05 Carnegie Hall, Headingley Campus, Leeds Beckett University, Leeds, W. Yorkshire, United Kingdom LS6 3QS.|Institute of Sport, Physical Activity and Leisure, G05 Carnegie Hall, Headingley Campus, Leeds Beckett University, Leeds, W. Yorkshire, United Kingdom LS6 3QS.
Roderick F G J
RF
King
Institute of Sport, Physical Activity and Leisure, G05 Carnegie Hall, Headingley Campus, Leeds Beckett University, Leeds, W. Yorkshire, United Kingdom LS6 3QS.|Institute of Sport, Physical Activity and Leisure, G05 Carnegie Hall, Headingley Campus, Leeds Beckett University, Leeds, W. Yorkshire, United Kingdom LS6 3QS.
Michael P
MP
Gray
Institute of Sport, Physical Activity and Leisure, G05 Carnegie Hall, Headingley Campus, Leeds Beckett University, Leeds, W. Yorkshire, United Kingdom LS6 3QS.|Institute of Sport, Physical Activity and Leisure, G05 Carnegie Hall, Headingley Campus, Leeds Beckett University, Leeds, W. Yorkshire, United Kingdom LS6 3QS.
Ben
B
Jones
D000293:Adolescent; D056352:Athletes; D015992:Body Mass Index; D001835:Body Weight; D003080:Cold Temperature; D003681:Dehydration / Q000517:prevention & control; D004326:Drinking; D015444:Exercise; D005538:Football; D006400:Hematocrit; D006454:Hemoglobins / Q000378:metabolism; D006706:Homeostasis; D006801:Humans; D008297:Male; D009994:Osmolar Concentration; D010953:Plasma Volume / Q000502:physiology; D012964:Sodium / Q000097:blood; D013546:Sweating; D013894:Thirst / Q000502:physiology*; D014882:Water-Electrolyte Balance / Q000502:physiology
D006454:Hemoglobins; D012964:Sodium
hydratation; hydration; hyponatremia; hyponatrémie; inconfort thermique; soif; sport d’équipe; team sport; thermal discomfort; thirst