title: The interrelationship between air temperature and humidity as applied locally to the skin: the resultant response on skin temperature and blood flow with age differences.
abstract: BACKGROUND
  Most studies of the skin and how it responds to local heat have been conducted with either water, thermodes, or dry heat packs. Very little has been accomplished to look at the interaction between air humidity and temperature on skin temperature and blood flow. With variable air temperatures and humidity's around the world, this, in many ways, is a more realistic assessment of environmental impact than previous water bath studies.
  
  
  METHODS
  Eight young and 8 older subjects were examined in an extensive series of experiments where on different days, air temperature was 38, 40, or 42°C. and at each temperature, humidity was either 0%, 25%, 50%, 75%, or 100% humidity. Over a 20 minute period of exposure, the response of the skin in terms of its temperature and blood flow was assessed.
  
  
  RESULTS
  For both younger and older subjects, for air temperatures of 38 and 40°C., the humidity of the air had no effect on the blood flow response of the skin, while skin temperature at the highest humidity was elevated slightly. However, for air temperatures of 42°C., at 100% humidity, there was a significant elevation in skin blood flow and skin temperature above the other four air humidity's (p<0.05). In older subjects, the blood flow response was less and the skin temperature was much higher than younger individuals for air at 42°C. and 100% humidity (p<0.05).
  
  
  CONCLUSIONS
  Thus, in older subjects, warm humid air caused a greater rise in skin temperature with less protective effect of blood flow to protect the skin from overheating than is found in younger subjects.
authors.affiliation: Department of Physical Therapy, Loma Linda University, Loma Linda, CA 92350, USA. jpetrofsky@llu.edu
authors.forename: Jerrold S
authors.initials: JS
authors.lastname: Petrofsky
authors.forename: Lee
authors.initials: L
authors.lastname: Berk
authors.forename: Faris
authors.initials: F
authors.lastname: Alshammari
authors.forename: Haneul
authors.initials: H
authors.lastname: Lee
authors.forename: Adel
authors.initials: A
authors.lastname: Hamdan
authors.forename: Jong Eun
authors.initials: JE
authors.lastname: Yim
authors.forename: Yusufi
authors.initials: Y
authors.lastname: Kodawala
authors.forename: Dennis
authors.initials: D
authors.lastname: Patel
authors.forename: Bhakti
authors.initials: B
authors.lastname: Nevgi
authors.forename: Gauri
authors.initials: G
authors.lastname: Shetye
authors.forename: Harold
authors.initials: H
authors.lastname: Moniz
authors.forename: Wei Ti
authors.initials: WT
authors.lastname: Chen
authors.forename: Mastour
authors.initials: M
authors.lastname: Alshaharani
authors.forename: Kunal
authors.initials: K
authors.lastname: Pathak
authors.forename: Sushma
authors.initials: S
authors.lastname: Neupane
authors.forename: Karunakar
authors.initials: K
authors.lastname: Somanaboina
authors.forename: Samruddha
authors.initials: S
authors.lastname: Shenoy
authors.forename: Sungwan
authors.initials: S
authors.lastname: Cho
authors.forename: Bargav
authors.initials: B
authors.lastname: Dave
authors.forename: Rajavi
authors.initials: R
authors.lastname: Desai
authors.forename: Swapnil
authors.initials: S
authors.lastname: Malthane
authors.forename: Hani
authors.initials: H
authors.lastname: Al-Nakhli
mesh_terms: D000328:Adult; D000368:Aged; D000375:Aging / Q000502:physiology*; D000388:Air; D005260:Female; D005542:Forearm / Q000502:physiology; D006801:Humans; D006813:Humidity; D008297:Male; D012039:Regional Blood Flow / Q000502:physiology*; D012867:Skin / Q000098:blood supply*; D012881:Skin Temperature / Q000502:physiology*; D013696:Temperature