Pilocarpine iontophoresis test: an index of physiological sweat secretion?
The pilocarpine iontophoresis test (P-test) is used as a predictor of the capacity to produce sweat. Therefore, we studied the reproducibility of this test in 12 normal subjects on 10 consecutive days. Furthermore, we determined whether the P-test reflects whole-body and regional sweat secretion during exercise in the heat. Finally, we determined whether the P-test stimulates the eccrine sweat glands to maximal sweat secretion. Six growth hormone-deficient (GHD) patients who are known to have decreased sweating, and 11 healthy control subjects were studied. To induce maximal sweat secretion, the patients exercised on a bicycle ergometer at a workload corresponding to 40% of their maximal aerobic power (VO2max). The 11 healthy subjects exercised at a workload of 150 W. All subjects exercised for 60 min in ambient air at 35 degrees C, with 50% relative humidity. The P-test showed a mean day-to-day variation of 20.8% between individual subjects. There was a significant positive correlation between the P-test and regional sweat secretion (r2 = 0.74). The correlation coefficient (r2) was 0.50 for the correlation between the P-test and whole-body sweat secretion, and 0.52 for the correlation between regional sweat secretion and whole-body sweat secretion. We conclude that the pilocarpine iontophoresis test reflects heat- and exercise-induced sweating capacity. However, this test does not induce maximal sweating, and it cannot be used as a single reliable predictor of whole-body sweating, due to considerable day-to-day variation.
Hjortskov
N
N
August Krogh Institute, University of Copenhagen, Denmark.
Jepsen
L T
LT
Nielsen
B
B
Juul
A
A
Skakkebaek
N E
NE
D000328:Adult; D015444:Exercise / Q000502:physiology; D005080:Exercise Test; D005260:Female; D006358:Hot Temperature; D006801:Humans; D006813:Humidity; D007478:Iontophoresis; D008297:Male; D018721:Muscarinic Agonists / Q000008:administration & dosage; D010101:Oxygen Consumption / Q000502:physiology; D010862:Pilocarpine / Q000008:administration & dosage; D013546:Sweating / Q000187:drug effects*
D018721:Muscarinic Agonists; D010862:Pilocarpine