10.1007_s40279-013-0051-z
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C O R R E S P O N D E N C E
Authors Reply to Periard: Cardiovascular DeterminantsInvolved in Pacing Under Heat Stress
The Complex Skill of Pacing: Is There an Interplay Between Central and Peripheral
Determinants?
B. Roelands J. de Koning C. Foster
F. Hettinga R. Meeusen
Published online: 9 May 2013
Springer International Publishing Switzerland 2013
By posing the question we already give the answer: the
time has passed when exercise physiologists divided thehuman body into a heart and muscles and the mysterious
brain. Exercise physiology integrates both and pacing is a
very nice example of the interplay between peripheral
factors including cardiovascular regulation, metabolism,
muscle physiology, and central factors such as neuro-
transmission, perception of effort, control of thermoregu-
lation, and others [1, 2]. We therefore thank Dr Periard for
his feedback [3] on our article and for pointing out the
importance of cardiovascular limitations during prolonged
exercise [4]. Indeed, cardiovascular limitations induced by
adjustments in thermoregulation can significantly influence
the maintenance of a given absolute intensity or pace, as
was stated by Periard. Evidence from studies in our labo-
ratory [57] showed that fixed-intensity exercise (60 min at55 % of the maximal power output) resulted in signifi-
cantly higher heart rates in hot conditions (30 C) when
compared with normal (18 C) ambient temperature.
Unfortunately, we did not measure stroke volume, cardiac
output, or blood flow as was done in the study by Periard
et al. [4] and that would have provided interesting infor-
mation. During the 30-min time trial that followed the
60-min fixed-intensity exercise, the observed difference in
heart rate disappeared. This could be explained by the
attainment of higher power outputs in normal conditions
compared with hot ambient conditions. Furthermore, from
10 min to the termination of exercise, heart rates followed
a similar pattern in both conditions. This outcome is not
identical to the findings of Periard et al. [4] but again
emphasizes the interplay between peripheral and central
aspects in pacing. Generally, these data demonstrate that
the cardiovascular system is a coinfluencer of exercise
performance (and thus pacing strategy) that cannot be
overlooked. The data also encourage scientists to further
unravel the mechanisms behind changes in pace and the
onset of fatigue, certainly during prolonged exercise bouts
in the heat.
In our review, we acknowledged the complexity of the
concept of pacing, and consequently the interplay between
peripheral and central factors. However, our main area of
expertise lies in the central aspects of fatigue and the
manipulation of brain neurotransmission in different ambient
settings [8]. Our review was therefore focused on the
central aspects of exercise in the heat, an area that has
gained more importance in the recent years. Furthermore, in
our article we directed interested readers to the excellent
review by Abbiss and Laursen [2], who described nine dif-
ferent models of fatigue, including the cardiovascular model.
This reply refers to the comment available at
doi:10.1007/s40279-013-0050-0.
B. Roelands R. Meeusen (&)
Department of Human Physiology, Faculty of Physical
Education and Physiotherapy, Vrije Universiteit Brussel,
Brussels, Belgium
e-mail: [email protected]
B. Roelands
Fund for Scientific Research Flanders (FWO), Brussels, Belgium
J. de Koning C. Foster
Research Institute MOVE, Faculty of Human Movement
Sciences, VU University, Amsterdam, The Netherlands
J. de Koning C. Foster
Department of Exercise and Sport Science, University of
Wisconsin, La Crosse, USA
F. Hettinga
University of Groningen, University Medical Center Groningen,
Center of Human Movement Sciences, Groningen,
The Netherlands
Sports Med (2013) 43:647648
DOI 10.1007/s40279-013-0051-z
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In conclusion, we feel that the letter written by Dr.
Periard clearly underlines the need for further research and
emphasis on how fatigue and pacing are surely not a
peripheral or central entity but rather a peripheral and
central phenomenon.
Acknowledgements Bart Roelands is a post-doctoral fellow of the
Fund for Scientific Research Flanders (FWO). The authors have noconflicts of interest that are directly relevant to the content of this
letter.
References
1. Roelands B, de Koning J, Foster C, et al. Neurophysiological
determinants of theoretical concepts and mechanisms involved in
pacing. Sports Med. 2013;43(5):30111. doi:10.1007/s40279-013-
0030-4.
2. Abbiss CR, Laursen PB. Models to explain fatigue during
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3. Periard JD. Cardiovascular determinants involved in pacing under
heat stress (letter). 2013. doi:10.1007/s40279-013-0050-0.
4. Periard JD, Cramer MN, Chapman PG, et al. Cardiovascular strain
impairs prolonged self-paced exercise in the heat. Exp Physiol.
2011;96(2):13444.
5. Roelands B, Hasegawa H, Watson P, et al. The effects of acute
dopamine reuptake inhibition on performance. Med Sci Sports
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