TY - JOUR
T1 - Physiological responses to incremental exercise in the heat following internal and external precooling
AU - James, C. A.
AU - Richardson, A. J.
AU - Watt, P. W.
AU - Gibson, O. R.
AU - Maxwell, N. S.
N1 - This supplement was supported by an unrestricted educational grant from Aspetar Orthopaedic and Sports Medicine Hospital.
Publisher Copyright:
© 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.
PY - 2015/6
Y1 - 2015/6
N2 - Twelve males completed three incremental, discontinuous treadmill tests in the heat [31.9(1.0)°C, 61.9(8.9)%] to determine speed at two fixed blood lactate concentrations (2 and 3.5mmol/L), running economy (RE), and maximum oxygen uptake ( V ˙ O 2 m a x ). Trials involved 20min of either internal cooling (ICE, 7.5g/kg ice slurry ingestion) or mixed-methods external cooling (EXT, cold towels, forearm immersion, ice vest, and cooling shorts), alongside no intervention (CON). Following precooling, participants ran 0.3km/h faster at 2mmol/L and 0.2km/h faster at 3.5mmol/L (P=0.04, partial η2=0.27). Statistical differences were observed vs CON for ICE (P=0.03, d=0.15), but not EXT (P=0.12, d=0.15). There was no effect of cooling on RE (P=0.81, partial η2=0.02), nor on V ˙ O 2 m a x (P=0.69, partial η2=0.04). An effect for cooling on physiological strain index was observed (P<0.01, partial η2=0.41), with differences vs CON for EXT (P=0.02, d=0.36), but not ICE (P=0.06, d=0.36). Precooling reduced thermal sensation (P<0.01, partial η2=0.66) in both cooling groups (P<0.01). Results indicate ICE and EXT provide similar physiological responses for exercise up to 30min duration in the heat. Differing thermoregulatory responses are suggestive of specific event characteristics determining the choice of cooling. Precooling appears to reduce blood lactate accumulation and reduce thermoregulatory and perceptual strain during incremental exercise.
AB - Twelve males completed three incremental, discontinuous treadmill tests in the heat [31.9(1.0)°C, 61.9(8.9)%] to determine speed at two fixed blood lactate concentrations (2 and 3.5mmol/L), running economy (RE), and maximum oxygen uptake ( V ˙ O 2 m a x ). Trials involved 20min of either internal cooling (ICE, 7.5g/kg ice slurry ingestion) or mixed-methods external cooling (EXT, cold towels, forearm immersion, ice vest, and cooling shorts), alongside no intervention (CON). Following precooling, participants ran 0.3km/h faster at 2mmol/L and 0.2km/h faster at 3.5mmol/L (P=0.04, partial η2=0.27). Statistical differences were observed vs CON for ICE (P=0.03, d=0.15), but not EXT (P=0.12, d=0.15). There was no effect of cooling on RE (P=0.81, partial η2=0.02), nor on V ˙ O 2 m a x (P=0.69, partial η2=0.04). An effect for cooling on physiological strain index was observed (P<0.01, partial η2=0.41), with differences vs CON for EXT (P=0.02, d=0.36), but not ICE (P=0.06, d=0.36). Precooling reduced thermal sensation (P<0.01, partial η2=0.66) in both cooling groups (P<0.01). Results indicate ICE and EXT provide similar physiological responses for exercise up to 30min duration in the heat. Differing thermoregulatory responses are suggestive of specific event characteristics determining the choice of cooling. Precooling appears to reduce blood lactate accumulation and reduce thermoregulatory and perceptual strain during incremental exercise.
KW - Endurance
KW - External cooling
KW - Ice slurry
KW - Lactate threshold
KW - Precooling
KW - Thermoregulation
UR - http://www.scopus.com/inward/record.url?scp=84928805220&partnerID=8YFLogxK
U2 - 10.1111/sms.12376
DO - 10.1111/sms.12376
M3 - Journal article
C2 - 25943670
AN - SCOPUS:84928805220
SN - 0905-7188
VL - 25
SP - 190
EP - 199
JO - Scandinavian Journal of Medicine and Science in Sports
JF - Scandinavian Journal of Medicine and Science in Sports
IS - S1
ER -