title: Temperature and blood flow distribution in the human leg during passive heat stress.
abstract: The influence of temperature on the hemodynamic adjustments to direct passive heat stress within the leg's major arterial and venous vessels and compartments remains unclear. Fifteen healthy young males were tested during exposure to either passive whole body heat stress to levels approaching thermal tolerance [core temperature (Tc) + 2°C; study 1; n = 8] or single leg heat stress (Tc + 0°C; study 2; n = 7). Whole body heat stress increased perfusion and decreased oscillatory shear index in relation to the rise in leg temperature (Tleg) in all three major arteries supplying the leg, plateauing in the common and superficial femoral arteries before reaching severe heat stress levels. Isolated leg heat stress increased arterial blood flows and shear patterns to a level similar to that obtained during moderate core hyperthermia (Tc + 1°C). Despite modest increases in great saphenous venous (GSV) blood flow (0.2 l/min), the deep venous system accounted for the majority of returning flow (common femoral vein 0.7 l/min) during intense to severe levels of heat stress. Rapid cooling of a single leg during severe whole body heat stress resulted in an equivalent blood flow reduction in the major artery supplying the thigh deep tissues only, suggesting central temperature-sensitive mechanisms contribute to skin blood flow alone. These findings further our knowledge of leg hemodynamic responses during direct heat stress and provide evidence of potentially beneficial vascular alterations during isolated limb heat stress that are equivalent to those experienced during exposure to moderate levels of whole body hyperthermia.
authors.affiliation: Centre for Human Performance, Exercise and Rehabilitation, Brunel University London, Uxbridge, United Kingdom.
authors.forename: Scott T
authors.initials: ST
authors.lastname: Chiesa
authors.affiliation: Centre for Human Performance, Exercise and Rehabilitation, Brunel University London, Uxbridge, United Kingdom.
authors.forename: Steven J
authors.initials: SJ
authors.lastname: Trangmar
authors.affiliation: Centre for Human Performance, Exercise and Rehabilitation, Brunel University London, Uxbridge, United Kingdom j.gonzalez-alonso@brunel.ac.uk.
authors.forename: José
authors.initials: J
authors.lastname: González-Alonso
mesh_terms: D000328:Adult; D001783:Blood Flow Velocity / Q000502:physiology; D001833:Body Temperature Regulation / Q000502:physiology; D005263:Femoral Artery / Q000503:physiopathology; D005268:Femoral Vein / Q000503:physiopathology; D018882:Heat Stress Disorders / Q000503:physiopathology*; D006439:Hemodynamics / Q000502:physiology; D006358:Hot Temperature; D006801:Humans; D006979:Hyperthermia, Induced / Q000379:methods; D007866:Leg / Q000098:blood supply* / Q000503:physiopathology*; D008297:Male; D012039:Regional Blood Flow / Q000502:physiology*; D013848:Thigh / Q000098:blood supply / Q000502:physiology; D055815:Young Adult
keywords: heat stress; hemodynamics; leg blood flow
references.citation: J Appl Physiol. 1969 Nov;27(5):673-80
references.pmid: 5360442
references.citation: Am J Physiol Heart Circ Physiol. 2011 Feb;300(2):H664-9
references.pmid: 21131471
references.citation: Biophys J. 2008 May 15;94(10):L78-80
references.pmid: 18339767
references.citation: Proc Nutr Soc. 1999 Nov;58(4):887-98
references.pmid: 10817156
references.citation: J Appl Physiol. 1973 Jul;35(1):77-84
references.pmid: 4716165
references.citation: Circulation. 2001 Apr 3;103(13):1752-8
references.pmid: 11282906
references.citation: Am J Physiol Regul Integr Comp Physiol. 2011 Mar;300(3):R663-73
references.pmid: 21178127
references.citation: Am Heart J. 1968 Dec;76(6):769-74
references.pmid: 5721834
references.citation: Physiol Rep. 2014 Jan 06;2(1):e00193
references.pmid: 24744872
references.citation: J Appl Physiol (1985). 1999 Sep;87(3):1163-71
references.pmid: 10484591
references.citation: Circulation. 2003 Jun 17;107(23 Suppl 1):I9-16
references.pmid: 12814980
references.citation: J Appl Physiol (1985). 1998 Apr;84(4):1323-32
references.pmid: 9516200
references.citation: J Clin Invest. 1966 Nov;45(11):1801-16
references.pmid: 5926447
references.citation: J Physiol. 1957 May 23;136(3):489-97
references.pmid: 13429515
references.citation: J Am Coll Cardiol. 2001 Oct;38(4):1083-8
references.pmid: 11583886
references.citation: J Appl Physiol. 1975 May;38(5):839-45
references.pmid: 1126893
references.citation: J Appl Physiol (1985). 2001 Oct;91(4):1619-26
references.pmid: 11568143
references.citation: Hypertension. 2009 Aug;54(2):278-85
references.pmid: 19546374
references.citation: J Appl Physiol. 1972 Apr;32(4):506-11
references.pmid: 5026500
references.citation: BMJ. 1995 Feb 18;310(6977):446
references.pmid: 7873953
references.citation: J Appl Physiol. 1964 May;19:531-3
references.pmid: 14173555
references.citation: J Appl Physiol (1985). 2011 Sep;111(3):818-24
references.pmid: 21680875
references.citation: Am J Physiol. 1994 Oct;267(4 Pt 2):H1337-40
references.pmid: 7943379
references.citation: Am J Physiol Heart Circ Physiol. 2015 Jul 15;309(2):H369-80
references.pmid: 25934093
references.citation: J Physiol. 2010 Oct 1;588(Pt 19):3799-808
references.pmid: 20693291
references.citation: Eur J Appl Physiol. 2007 Sep;101(1):97-103
references.pmid: 17520271
references.citation: Eur J Appl Physiol. 2014 Apr;114(4):859-65
references.pmid: 24399113
references.citation: Hypertension. 2010 Feb;55(2):312-8
references.pmid: 20048193
references.citation: J Appl Physiol (1985). 1990 Jul;69(1):376-9
references.pmid: 2394660
references.citation: J Physiol. 1956 Dec 28;134(3):612-9
references.pmid: 13398947
references.citation: Exp Physiol. 2012 Mar;97(3):419-32
references.pmid: 22227202
references.citation: Am J Physiol Regul Integr Comp Physiol. 2011 Feb;300(2):R486-91
references.pmid: 21084673
references.citation: J Appl Physiol (1985). 1993 May;74(5):2566-73
references.pmid: 8335593
references.citation: J Physiol. 1956 Nov 28;134(2):444-50
references.pmid: 13398924
references.citation: J Am Coll Cardiol. 2002 Mar 6;39(5):754-9
references.pmid: 11869837
references.citation: J Appl Physiol (1985). 1999 Apr;86(4):1185-90
references.pmid: 10194201
references.citation: J Physiol. 1957 Dec 31;139(3):455-65
references.pmid: 13492236
references.citation: Angiology. 1999 Aug;50(8):649-54
references.pmid: 10451232
references.citation: J Vasc Surg. 2002 Mar;35(3):527-31
references.pmid: 11877703
references.citation: Hypertension. 2009 Jun;53(6):986-92
references.pmid: 19380611
references.citation: Circ Res. 1995 Dec;77(6):1222-8
references.pmid: 7586235
references.citation: J Physiol. 1960 Sep;153(2):232-8
references.pmid: 16992060
references.citation: Am J Physiol Heart Circ Physiol. 2014 Nov 1;307(9):H1288-97
references.pmid: 25172894
references.citation: J Clin Invest. 1964 Aug;43:1677-90
references.pmid: 14201551