Jw. Williamson et al., Hypnotic manipulation of effort sense during dynamic exercise: cardiovascular responses and brain activation, J APP PHYSL, 90(4), 2001, pp. 1392-1399
The purpose of this investigation was to hypnotically manipulate effort sen
se during dynamic exercise and determine whether cerebral cortical structur
es previously implicated in the central modulation of cardiovascular respon
ses were activated. Six healthy volunteers (4 women, 2 men) screened for hi
gh hypnotizability were studied on 3 separate days during constant-load exe
rcise under three hypnotic conditions involving cycling on a 1) perceived l
evel grade, 2) perceived downhill grade, and 3) perceived uphill grade. Rat
ings of perceived exertion (RPE), heart rate (HR), blood pressure (BP), and
regional cerebral blood flow (rCBF) distributions for several sites were c
ompared across conditions using an analysis of variance. The suggestion of
downhill cycling decreased both the RPE [from 13 +/- 2 to 11 +/- 2 (SD) uni
ts; P < 0.05] and rCBF in the left insular cortex and anterior cingulate co
rtex, but it did not alter exercise HR or BP responses. Perceived uphill cy
cling elicited significant increases in RPE (from 13 +/- 2 to 14 +/- 1 unit
s), HR (+16 beats/min), mean BP (+7 mmHg), right insular activation (+7.7 /- 4%), and right thalamus activation (+9.2 +/- 5%). There were no differen
ces in rCBF for leg sensorimotor regions across conditions. These findings
show that an increase in effort sense during constant-load exercise can act
ivate both insular and thalamic regions and elevate cardiovascular response
s but that decreases in effort sense do not reduce cardiovascular responses
below the level required to sustain metabolic needs.