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Two studies were conducted to examine the effects of ice slushy ingestion (ICE) and cold water immersion (CWI) on thermoregulatory and sweat responses during constant (study 1) and self-paced (study 2) exercise. In study 1, 11 men cycled at 40–50% of peak aerobic power for 60 min (33.2 ± 0.3°C, 45.9 ± 0.5% relative humidity, RH). In study 2, 11 men cycled for 60 min at perceived exertion (RPE) equivalent to 15 (33.9 ± 0.2°C and 42.5 ± 3.9%RH). In both studies, each trial was preceded by 30 min of CWI (~22°C), ICE or no cooling (CON). Rectal temperature (Tre), skin temperature (Tsk), thermal sensation, and sweat responses were measured. In study 1, ICE decreased Tre-Tsk gradient versus CON (p = 0.005) during first 5 min of exercise, while CWI increased Tre-Tsk gradient versus CON and ICE for up to 20 min during the exercise (p<0.05). In study 2, thermal sensation was lower in CWI versus CON and ICE for up to 35–40 min during the exercise (p<0.05). ICE reduced thermal sensation versus CON during the first 20 min of exercise (p<0.05). In study 2, CWI improved mean power output (MPO) by ~8 W, compared with CON only (p = 0.024). In both studies, CWI (p<0.001) and ICE (p = 0.019) delayed sweating by 1–5 min but did not change the body temperature sweating threshold, compared with CON (both p>0.05). Increased Tre-Tsk gradient by CWI improved MPO while ICE reduced Tre but did not confer any ergogenic effect. Both precooling treatments attenuated the thermal efferent signals until a specific body temperature threshold was reached. [ABSTRACT FROM AUTHOR]

This study compared the effect of postexercise water immersion ( WI) at different temperatures on common femoral artery blood flow ( CFA), muscle (total haemoglobin; tHb) and skin perfusion (cutaneous vascular conductance; CVC), assessed by Doppler ultrasound, near-infrared spectroscopy (NIRS) and laser Doppler flowmetry, respectively. Given that heat stress may influence the vascular response during cooling, nine men cycled for 25 min at the first ventilatory threshold followed by intermittent 30-s cycling at 90% peak power until exhaustion at 32·8 ± 0·4°C and 32 ± 5% RH. They then received 5-min WI at 8·6 ± 0·2°C ( WI9), 14·6 ± 0·3°C ( WI15), 35·0 ± 0·4°C ( WI35) or passive rest ( CON) in a randomized, crossover manner. Heart rate ( HR), mean arterial pressure ( MAP), muscle ( Tmu), thigh skin ( Tthigh), rectal ( Tre) and mean body ( Tbody) temperatures were assessed. At 60 min postimmersion, decreases in Tre after WI35 (−0·6 ± 0·3°C) and CON (−0·6 ± 0·3°C) were different from WI15 (−1·0 ± 0·3°C; P<0·05), but not from WI9 (−1·0 ± 0·3°C; P = 0·074-0·092). WI9 and WI15 had reduced Tbody, Tthigh and Tmu compared with WI35 and CON ( P <0·05). CFA, tHb and CVC were lower in WI9 and WI15 compared with CON ( P<0·05). tHb following WI9 remained lower than CON ( P = 0·044) at 30 min postimmersion. CVC correlated with tHb during non-cooling ( WI35 and CON) ( r2 = 0·532; P<0·001) and cooling recovery ( WI9 and WI15) ( r2 = 0·19; P = 0·035). WI9 resulted in prolonged reduction in muscle perfusion. This suggests that CWI below 10°C should not be used for short-term (i.e. <60 min) recovery after exercise. [ABSTRACT FROM AUTHOR]