Seong Dae Kim1, Il Gyu Jeong1, Yun Suk Koh2, Hee-Hyuk Lee1
1Department of Sports Science, Hannam University, Daejeon, Korea 2Department of Health, Human Performance and Recreation, Baylor University, Waco, TX, USA
Background: The cerebral blood flow velocity (CBFV) and
rate pressure product (RPP) have been reported to benefit
hemodynamics more during exercise in the recumbent
position than during that in the upright position.
However, it is unclear which angle is of the greatest benefit
to hemodynamics during exercise in the recumbent
position. This study aimed to evaluate the effect of the
recumbent angle on CBFV and RPP during exercise.
Methods: In a balanced crossover study, 15 healthy
volunteers (age, 18.7¡¾1.1 years) were asked to perform
the bicycle exercise four times in the upright and at
recumbent angles of 67¡Æ (R), 47¡ÆR, and 15¡ÆR, with weekly
intervals between each condition. The exercise intensity
was set initially at 50 W and increased by 25 W every 2
minutes up to 150 W. CBFV in the middle cerebral artery
(MCA) was measured using transcranial doppler
sonography. All data were analyzed using two-way
repeated-measures analysis of variance.
Results: CBFV at 15¡ÆR was significantly higher than that in
the upright position and at 67¡ÆR at 10 minutes recov-
ery (69¡¾16 vs. 56¡¾7 and 58¡¾10 cm/s, respectively; P<0.05).
The RPP was significantly lower at 67¡ÆR, 47¡ÆR, and 15¡ÆR than
in the upright position immediately after exercise (176¡¾23,
177¡¾22, and 173¡¾26, respectively, vs. 241¡¾42
mmHg¡¿beats/min¡¿10-2; P<0.001).
Conclusions: At an angle of less than 67¡ÆR, exercise
increases CBFV and reduces RPP, relative to those during
exercise in the upright position. This hemodynamic effect
was most prominent at 15¡ÆR, where cerebral circu- lation
was further increased in the recovery phase.
Korean J Health Promot 2019;19(3):155-160
Keywords: Posture, Exercise, Cerebrovascular circulation,
Hemodynamics |