Enter your Email address:
Wolters Kluwer Health may email you for journal alerts and information, but is committed
to maintaining your privacy and will not share your personal information without
Wilson, T E.1,2; Cui, J1; Crandall, C G. FACSM1,3
1Institute for Exercise and Environmental Medicine
2Southwest Missouri State University
3University of Texas Southwestern Medical Center
The cutaneous venoarteriolar response (VAR) decreases blood flow via non-adrenergic mechanisms secondary to local increases in venous pressure. Orthostatic tolerance is reduced in heat stressed individuals. Reduced vasoconstriction during engagement of the VAR in heat stressed individuals may contribute to reduced orthostatic tolerance in this condition.
To identify the effects of whole-body heating on the cutaneous VAR.
12 subjects underwent whole-body heating by perfusing warm water (46°C) through a tube-lined suit. Cutaneous vascular conductance (CVC; dorsal foot and forearm), internal temperature, mean skin temperature, and arterial blood pressure were measured throughout the protocol. During normothermic conditions (mean skin temperature 34°C), and every 10 min during heating until internal temperature increased by 1°C, individuals were exposed to 30° head-up tilt for 2 min. VAR was invoked in the foot with tilting but not in the forearm, as the forearm was maintained at heart level.
Results varied among subjects and among a given increase in internal temperature. Vasoconstriction associated with the VAR during normothermia was present but relatively small. With slight heating (presumably with removal of tonic vasoconstrictor tone) the magnitude of vasoconstriction due to the VAR was augmented. After more pronounced heating, vasoconstriction due to the VAR was either augmented (n = 2), attenuated (n = 2), absent (n = 2), or reversed (i.e., vasodilation in the area of measurement instead of vasoconstriction; n = 6). Forearm CVC showed small decreases during tilt and responses were accentuated as the heat stress progressed.
Pronounced indirect whole-body heating can reduce the magnitude of vasoconstriction of the cutaneous VAR, with the majority of subjects showing either an absence of vasoconstriction or vasodilation during engagement of the VAR in this condition. Funded in part by NIH (HL-61388 & 10488)
©2003The American College of Sports Medicine
Colleague's E-mail is Invalid
Your Name: (optional)
Separate multiple e-mails with a (;).
Thought you might appreciate this item(s) I saw at Medicine & Science in Sports & Exercise.
Send a copy to your email
Your message has been successfully sent to your colleague.
Some error has occurred while processing your request. Please try after some time.
An Existing Folder
A New Folder
The item(s) has been successfully added to "".
Login with your LWW Journals username and password.
Username or Email:
Enter and submit the email address you registered with. An email with instructions to reset your password will be sent to that address.
Link to reset your password has been sent to specified email address.
What does "Remember me" mean?
By checking this box, you'll stay logged in until you logout. You'll get easier access to your articles, collections,
media, and all your other content, even if you close your browser or shut down your
To protect your most sensitive data and activities (like changing your password),
we'll ask you to re-enter your password when you access these services.
What if I'm on a computer that I share with others?
If you're using a public computer or you share this computer with others, we recommend
that you uncheck the "Remember me" box.
Save my selection
Article Level Metrics