Coronary blood flow after cold exposure and the effect of warm-up exercise.
BACKGROUND
Cold pressor test (CPT) results indicate that coronary blood flow (CBF) increases after sudden cold exposure. Traditionally, warm-up exercise (WEx) has been recommended before cold exposure; however, the physiologic effects of WEx on CBF have not been elucidated. Therefore, this study was undertaken to evaluate the effect of WEx on CBF after cold exposure.


METHODS
Fifteen healthy young men were enrolled in this study. CBF at the distal left anterior descending coronary artery was assessed by transthoracic Doppler echocardiography at baseline and after CPT. The same measurements were made with WEx and weight-bearing exercise before CPT after a 20-minute recovery period between each measurement. In the CBF velocities, the time-velocity integral of diastolic flow (Dtvi) was measured in addition to blood pressure and heart rate (HR).


RESULTS
The product of Dtvi x HR increased significantly after CPT. Increments in Dtvi x HR after CPT with WEx before CPT were significantly higher than CPT alone (130 +/- 82% vs 68 +/- 37%, P < .05). However, increments in Dtvi x HR after CPT with weight-bearing exercise before CPT were not significantly different from those observed for CPT alone (74 +/- 50% vs 68 +/- 37%, P = not significant).


CONCLUSIONS
Our study suggests that WEx can augment an increased CBF after cold exposure. This augmentation of CBF increase after cold exposure may help the body meet increased physiologic demands imposed on it by cold exposure. However, this phenomenon was not observed for anaerobic weight-bearing exercise.
Division of Cardiology, Department of Internal Medicine, Seoul National University College of Medicine, Chongno-gu, Seoul, Korea.
Hyung-Kwan
HK
Kim
Dae-Won
DW
Sohn
Sang-Eun
SE
Lee
Yong-Jin
YJ
Kim
Byung-Hee
BH
Oh
Young-Bae
YB
Park
D000222:Adaptation, Physiological / Q000502:physiology; D000328:Adult; D001783:Blood Flow Velocity / Q000502:physiology*; D003080:Cold Temperature; D003326:Coronary Circulation / Q000502:physiology*; D003331:Coronary Vessels / Q000000981:diagnostic imaging* / Q000502:physiology*; D004452:Echocardiography; D015444:Exercise / Q000502:physiology*; D006801:Humans; D008297:Male; D005082:Physical Exertion / Q000502:physiology*