Hot-water immersion does not increase postprandial muscle protein synthesis rates during recovery from resistance-type exercise in healthy, young males

• Published in: Journal of applied physiology (1985) 2020-04, Vol.128 (4), p.1012-1022
• Main Authors: Fuchs, Cas J, Smeets, Joey S J, Senden, Joan M, Zorenc, Antoine H, Goessens, Joy P B, van Marken Lichtenbelt, Wouter D, Verdijk, Lex B, van Loon, Luc J C
• Format: Article
• Language: English
• Subjects: Adult; Amino acids; Carbohydrates; Diet; Dietary Proteins - administration & dosage; Hot Temperature; Humans; Immersion; Leg; Leucine; Male; Milk; Muscle Proteins - biosynthesis; Muscle, Skeletal; Muscles; Phenylalanine; Postprandial Period; Protein biosynthesis; Protein synthesis; Proteins; Recovery; Resistance Training; Starvation; Submerging; Water; Water immersion; Young Adult
• ISSN: 8750-7587; 1522-1601
• DOI: 10.1152/japplphysiol.00836.2019

The purpose of this study was to assess the impact of postexercise hot-water immersion on postprandial myofibrillar protein synthesis rates during recovery from a single bout of resistance-type exercise in healthy, young men. Twelve healthy, adult men (age: 23 ± 1 y) performed a single bout of resistance-type exercise followed by 20 min of water immersion of both legs. One leg was immersed in hot water [46°C: hot-water immersion (HWI)], while the other leg was immersed in thermoneutral water (30°C: CON). After water immersion, a beverage was ingested containing 20 g intrinsically L-[1- C]-phenylalanine and L-[1- C]-leucine labeled milk protein with 45 g of carbohydrates. In addition, primed continuous L-[ - H ]-phenylalanine and L-[1- C]-leucine infusions were applied, with frequent collection of blood and muscle samples to assess myofibrillar protein synthesis rates in vivo over a 5-h recovery period. Muscle temperature immediately after water immersion was higher in the HWI compared with the CON leg (37.5 ± 0.1 vs. 35.2 ± 0.2°C; < 0.001). Incorporation of dietary protein-derived L-[1- C]-phenylalanine into myofibrillar protein did not differ between the HWI and CON leg during the 5-h recovery period (0.025 ± 0.003 vs. 0.024 ± 0.002 MPE; = 0.953). Postexercise myofibrillar protein synthesis rates did not differ between the HWI and CON leg based upon L-[1- C]-leucine (0.050 ± 0.005 vs. 0.049 ± 0.002%/h; = 0.815) and L-[ - H ]-phenylalanine (0.048 ± 0.002 vs. 0.047 ± 0.003%/h; = 0.877), respectively. Hot-water immersion during recovery from resistance-type exercise does not increase the postprandial rise in myofibrillar protein synthesis rates. In addition, postexercise hot-water immersion does not increase the capacity of the muscle to incorporate dietary protein-derived amino acids in muscle tissue protein during subsequent recovery. This is the first study to assess the effect of postexercise hot-water immersion on postprandial myofibrillar protein synthesis rates and the incorporation of dietary protein-derived amino acids into muscle protein. We observed that hot-water immersion during recovery from a single bout of resistance-type exercise does not further increase myofibrillar protein synthesis rates or augment the postprandial incorporation of dietary protein-derived amino acids in muscle throughout 5 h of postexercise recovery.