Isolated diastolic pressure

[venkat_reddy]

I am 32 year old living in South India.  I observed that during summer (heat 40 degrees above) I used to feel frequently uneasiness in breathing and giddiness. From 2 weeks suffering from giddiness. My BP was 140/100. With some exercises and no stress it now come around 130/100.  But my DBP was around 100 consistently. What to do? I do exercises regularly and no habits of smoking, alkohal. Kindly suggest me in this regard.  Thank you.

[kenkeith]

The only variable (temperature) you post is climatic temperature so the appropriate response would be blood pressure regulation and climate not withstanding other variables  (different activities, different diet, drinking more alcohol, etc)..

For some insight: The regulation of systemic blood pressure is complex, involving a number of systems, but there are 3 areas in which a climatic influence has been clearly identified. They are cardiac output, peripheral resistance (degree of constriction would influence diastolic pressure) and stroke volume of blood.

The contribution of the heart to the regulation of blood pressure is through changes in cardiac output. Cardiac output is defined as the product of heart rate and stroke volume.
Either can be modified by climatic forces. The heart rate component is regulated by the autonomic nervous system, so its level of activity depends on the intensity of the stimulus at the time.

The second component of cardiac output , it normally reflects the amount of blood returned to the heart through the venous system (vessel constriction will raise diastolic PB).  If the vessels didn't contract, the empty parts may become filled with gas pockets, a very dangerous condition.  So this contraction is a necessary defensive maneuver. But what the body gains in one respect it loses in another. That's because this contraction causes increased tension in the vessels. In other words, high blood pressure.

[ed34]

Firstly the obvious thing to ask is are you drinking enough fluids in the heat. Although a lack in fluids would cause lower blood pressure, your heart will try to compensate in the first stages by working harder.