EFFECTS OF HEAT AND INTERMITTENT EXERCISE ON LEUKOCYTE AND SUB-POPULATION CELL COUNTS

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Authors
  1. Severs, Y.
  2. Brenner, I.
  3. Shek, P.N.
  4. Shephard, R.J.
Corporate Authors
Defence and Civil Inst of Environmental Medicine, Downsview ONT (CAN)
Abstract
The study examined the combined effects of heat stress and intermittent exercise on circulating leukocyte and sub-population cell counts. Using a randomized-block desing, 11 healthy male subjects (mean (SD) age = 29.1 (3.0) years maximal oxygen consumption (VO2max) = 4.76 (6.1) ml/(kg-min)) were assigned to four conditions. Each subject exercised on a cycle ergometer at 50% VO2max (two 30-min bouts, with 45 min rest between), or acted as his own control by sitting at 23C, or at 40C, 30% relative humidity, ofr 3 h. Blood samples taken prior to, during, and after each rest and exercise bout, and at corresponding times when sitting were used for Coulter cell counter and flow cytometric analysis. Sitting conditions did not produce any significant immunological changes. Intermittent exercise induced a biphasic response of granulocytosis, monocytosis and lumphocytosis, with a return to baseline between exercise bouts, samples showed a consistent granulocytosis, monocytosis and lumophocytosis (CD3+, CD4+, CD8+ and CD19+ cell counts). The second exercise bout produced a larger response than the first, further exacerbated when exercising at 40C. We concluded there is a synergism between heat and exercise exposure. An increase in core temperature and exercise stress recruit leukocytes into the peripheral circulation, with potentiation of the response during a second bout of exercise. TRUNCATED
Keywords
Granulocytes
Report Number
DCIEM-RP-96-P-05 — Reprint
Date of publication
12 Jan 1996
Number of Pages
12
Reprinted from
Eur J. Appl Physiol, vol 74, 1996, p 234-245
DSTKIM No
97-03519
CANDIS No
503678
Format(s):
Hardcopy;Document Image stored on Optical Disk

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