Acute Changes in Carotid Arterial Blood Velocity Immediately after

the Cessation of Exercise

Midori Tanaka

, Motoaki Sugawara

, Yasuo Ogasawara

, Kiyomi Niki

and Tadafumi Izumi

Faculty of Health Care Sciences, Himeji Dokkyo University, Himeji, Japan

Department of Medical Engineering, Kawasaki Medical School, Kurashiki, Japan

Biomedical Engineering Department, Tokyo City University, Tokyo, Japan

School of Rehabilitation Sciences, Health Sciences University of Hokkaido, Tobetsu, Hokkaido, Japan

1 OBJECTIVES

Changes in hemodynamic parameters following

exercise have been widely reported. However, the

changes in carotid arterial blood flow have not been

well documented. The purpose of this study was to

examine acute changes in carotid arterial blood

velocity immediately after the cessation of exercise.

2 METHODS

Twenty-four young healthy men were registered

(age: 21.3 ± 1.6 years). The cardiopulmonary

exercise test was conducted starting at an initial

workload of 20 W and lasting for 2 minutes with a

strength ergometer; thereafter, the workload was

increased stepwise by 20 W at 1-minute intervals.

Electrocardiogram was continuously monitored. The

criteria for the endpoint included increase of heart

rate to [(220-age) ×0.8 (bpm)], and achievement of

maximum fatigue or the impossibility of continuing

exercise. Then cooling down was conducted at 20 W

following exercise for 150s. We measured the blood

velocity in the carotid artery at 60s and 120s after

the cessation of exercise with a Doppler system. We

also measured carotid arterial diameter by echo

tracking (Niki, 2002). Carotid arterial stroke volume

(FV) was obtained by integrating the product of

blood velocity and arterial cross-section over systole.

Carotid arterial output (Q) was given as FV times

heart rate. The data were analyzed by the repeated

measures ANOVA and Bonferroni post test.

3 RESULTS

Reductions in systolic/ diastolic blood pressure were

significant at 60s and 120s after the cessation of

exercise (93 ± 3 / 84 ± 3% , 88 ± 4 / 84 ± 3%,

respectively) compared with the values at the

cessation of exercise (100%). The reduction in heart

rate was also significant at 60s and 120s after the

cessation of exercise (84 ± 7% and 78 ± 7%,

respectively). On the contrary, the maximum blood

velocity increased significantly to 121 ± 24 % and

116 ± 27% at 60s and 120s after the cessation of

exercise, respectively (Fig. 1). FV also increased

significantly to 128±40% and 129±42%. However,

Q remained unchanged.

Figure 1: The maximum carotid arterial blood velocities at

rest, at the cessation of exercise, 60s and 120s after the

cessation of exercise. Data are displayed as percent,

normalized to the velocity at the cessation of exercise.

4 DISCUSSION

Following exercise, syncope is often reported

(DiVasta, 2004; Natarajan, 2006; Vettor, 2015).

However, its hemodynamic mechanism is not yet

fully understood. The responses in blood flow (or

velocity) following exercise are not well

documented even though there has been extensive

work done on the blood pressure and heart rate

responses. The blood pressure and heart rate started

to decrease immediately after the cessation of

Tanaka, M., Sugawara, M., Ogasawara, Y., Niki, K. and Izumi, T..

Acute Changes in Carotid Arterial Blood Velocity Immediately after the Cessation of Exercise.

exercise as reported so far

(Muendel, 2015). On the

other hand, carotid arterial blood velocity increased

further after the cessation of exercise. Carotid

arterial stroke volume (FV) also increased, which

compensated for the reduction in output due to the

decrease in heart rate. Thus, carotid arterial output

(Q) remained unchanged. We consider that this is a

mechanism to prevent hemodynamic disturbance

after cessation of exercise.

5 CONCLUSIONS

Immediately after the cessation of exercise, blood

pressure and heart rate decreased. However, carotid

arterial blood velocity and stroke volume increased

significantly. As a result carotid arterial output

remained unchanged. This is considered to be a

mechanism to prevent post-exercise hemodynamic

disturbances.

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Niki, K., Sugawara, M., Chang, D., et al., 2002. A new

noninvasive measurement system for wave intensity:

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DiVasta, A. D., Alexander M.E., 2004. Fainting freshmen

and sinking sophomores: cardiovascular issues of the

adolescent. Curr Opin Pediatr.;16(4):350-6.

Natarajan, B., Nikore, V. 2006. Syncope and near syncope

in competitive athletes. Curr Sports Med Rep;

5(6):300-6.

Vettor, G., Zorzi, A., Basso, C ， 2015. Syncope as a

Warning Symptom of Sudden Cardiac Death in

Athletes. Cardiol Clin; 33(3):423-32. doi:

10.1016/j.ccl.2015.04.010.

Muendel, T., Perry, B.G., Ainslie, P.N., et al., 2015. Post-

exercise orthostatic intolerance: Influence of exercise

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