Cold-Water Immersion and Lower Limb Muscle Oxygen Consumption as Measured by Near-Infrared Spectroscopy in Trained Endurance Athletes.

SKELETAL muscle physiology; COLD (Temperature); LEG; DATA analysis; STATISTICAL significance; STATISTICAL sampling; HEMOGLOBINS; NEAR infrared spectroscopy; EVALUATION of medical care; RANDOMIZED controlled trials; DESCRIPTIVE statistics; COLD therapy; IMMERSION in liquids; ATHLETES; CROSSOVER trials; WATER; PHYSICAL fitness; STATISTICS; ANALYSIS of variance; OXYGEN consumption; ENDURANCE sports training; DATA analysis software

Cold-water immersion (CWI) has been reported to reduce tissue metabolism postimmersion, but physiological data are lacking regarding the muscle metabolic response to its application. Near-infrared spectroscopy (NIRS) is a noninvasive optical technique that can inform muscle hemodynamics and tissue metabolism. To investigate the effects of CWI at 2 water temperatures (10°C and 15°C) on NIRS-calculated measurements of muscle oxygen consumption (mVO2). Crossover study. University sports rehabilitation center. A total of 11 male National Collegiate Athletic Association Division II long-distance runners (age = 23.4 ± 3.4 years, height = 1.8 ± 0.1 m, mass = 68.8 ± 10.7 kg, mean adipose tissue thickness = 6.7 ± 2.7 mm). Cold-water immersion at 10°C and 15°C for 20 minutes. We calculated mVO2 preimmersion and postimmersion at water temperatures of 10°C and 15°C. Changes in tissue oxyhemoglobin (O2Hb), deoxyhemoglobin (HHb), total hemoglobin (tHb), hemoglobin difference (Hbdiff), and tissue saturation index (TSI %) were measured during the 20-minute immersion at both temperatures. We observed a decrease in mVO2 after immersion at both 10°C and 15°C (F1,9 = 27.7801, P =.001). During the 20-minute immersion at both temperatures, we noted a main effect of time for O2Hb (F3,27 = 14.227, P =.001), HHb (F3,27 = 5.749, P =.009), tHb (F3,27 = 24.786, P =.001), and Hbdiff (F3,27 = 3.894, P =.020), in which values decreased over the course of immersion. Post hoc pairwise comparisons showed that these changes occurred within the final 5 minutes of immersion for tHb and O2Hb. A 20-minute CWI at 10°C and 15°C led to a reduction in mVO2. This was greater after immersion at 10°C. The reduction in mVO2 suggests a decrease in muscle metabolic activity (ie, O2 use after CWI). Calculating mVO2 via the NIRS-occlusion technique may offer further insight into muscle metabolic responses beyond what is attainable from observing the NIRS primary signals. [ABSTRACT FROM AUTHOR]

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