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Answer to your Health Question

Question (03/24 /2012):

Title: Average blood pressure increase per increase in heart rate during fight or flight .

 

What is the average blood pressure increase per increase in heart rate during fight or flight?

What is the average increase in blood pressure per increase in heart rate during an increase in physical activity?

I would deeply appreciate answers to these questions-I've been looking all over the place for them.

Thank you

Kent

Answer:

Dear Kent,

There are no numbers for the first question but there are for the second.

A fight or flight response is a general discharge of the sympathetic nervous system.

The sympathetic nervous system increases heart rate.

An average healthy reading of blood pressure is 120/80 mm Hg and an average healthy heart rate 60 BPM o beats per minute.

In average healthy people there is no good correlation between pulse rate and blood pressure.

The environmental temperature, age, sex, and prior physical condition modify the correlation between blood pressure and heart rate.

In some abnormal cardiac rhythms (Atrial fibrillation, Ventricular tachycardia) a very high pulse rate causes a fall in blood pressure because the heart muscle is not contracting in the usual coordinated way to be an effective pump.

Different kinds of activity affect blood pressure differently.

The autonomic nervous system and its sympathetic arm play important roles in the regulation of blood pressure.

Muscle sympathetic nerve activity (MSNA) after arousal stimuli (eg, startling the subject with a loud noise) either does not change or falls for a few bursts in some subjects, and MSNA can fall during mental stress (Donadio V, Kallio M, Karlsson T, Nordin M, and Wallin BG).

In normotensive subjects with high levels of baseline MSNA, a relatively low value for cardiac output (CO) would offset the influence of higher sympathetic nerve activity and vascular resistance.

In young men, there is an inverse relationship between MSNA and CO.

This relationship helps explain why blood pressure is not consistently higher in subjects with high levels of MSNA.

In a large group of men and women <40 years of age, no relationship between MSNA and mean arterial pressure was seen by Narkiewicz et al. .

By contrast, in older men there was a modest relationship between MSNA or sympathetic nerve activity and blood pressure.

This positive relationship was more pronounced in the older women.

In healthy older subjects free of coexisting disease, there is a rise in sympathetic activity with aging.

In spite of the increased sympathetic activity with aging, the relationship between MSNA and blood pressure remains modest in older men.

Obesity and weight gain are conditions associated with increased MSNA or Muscle sympathetic nerve activity after arousal stimuli

You can find the answer to the second question at:

Average increase in blood pressure per increase in heart rate during an increase in physical activity


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