Why Your Heart Rate Increases At Open Water Finishes

Why Your Heart Rate Increases At Open Water Finishes

HUNTINGTON BEACH. When open water swimmers exit the water at the finish, there is almost always a corresponding spike in their heart rate that go beyond sprinting to the finish.

Why?

When your body shifts from one posture to another (e.g., from the horizontal position while swimming to the vertical position while running or dolphining out of the water), the blood in your heart and lungs naturally tends to move towards your legs due to the influence of gravity. As the blood moves towards your lower limbs, the veins in your legs expand and venous pooling (accumulation of blood in the legs) occurs.

When your are in the vertical position, the parts of your body in higher positions than your heart experience a decrease in arterial blood pressure. Conversely, the parts of your body below your heart experience an increase in blood pressure. When the average adult stands up, there is typically a rise in venous blood pressure in the lower limbs to 90 mmHg. When the veins in your legs expand and pooling occurs, the rate of venous return (blood flow back to your heart) correspondingly decreases. As a result, your heart’s stroke volume decreases and a transient drop in blood pressure is created.

As your blood pressure falls to compensate for this change, the sympathetic nervous system kicks into action and your heart rate increases along with the vascular resistance. Consequently, your blood pressure recovers and a balance is maintained as your heart rate spikes when you stop swimming and start running to the finish.

In order to help you adapt to these changes from the swimming position to the running (or walking) position, deck-ups are a great way to help you improve and become accustomed to this sudden heart spike and get better prepared for a fast finish.

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