postural hypotension

[natty23]

anyone know the physiology behind postural hypotension?

[woofgang]

basically, you stand up but your blood doesn't!!

http://cancerweb.ncl.ac.uk/cgi-bin/omd?postural+hypotension.

Normally when you change position upwards, your body readys itself by sending messages to your lower half to tense muscles to keep your blood where it is and push it upwards against gravity so that it travels upwards with the rest of your body

If your blood pressure is already lowered by drugs, unnoticed bleeding or dehydration, or you are at a time when your blood pressure is naturally low, eg on waking, then this may not be enough to keep the blood supply to your brain uninterrupted. This results in brief headache, dizziness and or fainting/blackouts

If you have neurological damage, then the mechanism that sends the message or takes the action may not function properly.

If you are old or have weak muscles for another reason, then they may not be able to tighten enought to make a difference.

You may have any combination of the above.

Some people's natural blood pressure is low without having a reason and these are also at risk of postural hypotension

[mfewell]

If you have problems first thing in the morning, lay in bed and vigorously stretch and flex your limb muscles like a cat does ! It helps to get the blood moving and tones you up a bit.