2007, Piran, Slovenia

Sweating
Figure 1: A quadrant diagram for the prediction of sweat rate and sweat sodium loss in
women (follicular phase) from steady-state heart rates, during exercise at 36 o C. Data points,
with bi-directional error bars, were derived at five different exercise steady-states. Solid lines
are regression curves with 99% confidence limits.
DISCUSSION
It is universally recognised that prediction equations work reasonably well when applied to
the subjects who actually participated in the original research, or to those who have physical
and physiological characteristics closely resembling those subjects. However, the integrity of
such predictions is challenged when they are applied to heterogeneous samples. This problem
can be rectified, to some extent, by the derivation of families of curves. For instance, we have
already established these curves for young adult males. For each gender, changes in the
curves within these quadrants will occur due to changes in endurance fitness and heat
adaptation status. Of course, the relationships for women may well be different during the
luteal phase. One may also wish consider the influence of ageing. Finally, one must allow for
variations in the environmental conditions, which can have a dramatic impact upon three of
the four quadrants. It is hoped that some may find this exercise stimulating. If not, then we
hope that you have at least enjoyed the diagram.
REFERENCES
Astrand, P.-O., and Ryhming, I. (1954). A nomogram for calculation of aerobic capacity
(physical fitness) from pulse rate during submaximal work. J. Appl. Physiol. 7:218-225.
Cage, G.W., and Dobson, R.L. (1965). Sodium secretion and reabsorption in the human
eccrine sweat gland. J. Clin. Invest. 44:1270-1276.
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