orthostatic hypotension

What's indicated by sensation of vibration under the skin, in this seting: shortly after lunch I worked several minutes on hands/knees in shade ~ 75 deg F; upon rising I felt lightheaded, weak, nauseous, but no pain or pressure, I lied down on lawn; for few minutes I sensed high frequency vibration under my skin in hands/arms; my wife brought water and BP cuff - BP was 89/70+, pulse 68; after 15' I sat up - BP 94, and 5' later I stood and walked into the house; BP rose to 114 in 20', but 20' later back to 90; I lied down and slept 2 hours, then felt normal - BP 120/78.  (Typical BP is 125-140/74-80, pulse 64-72.)
    14 months earlier after using chainsaw, had similar symptoms with temporary loss of vision (still conscious) - no BP taken.  Subsequent stress test, electrocardiogram normal, postural differences in BP noted.
    ~ 18 years ago, similar symptoms after stess test - lied down 20' to recover.  Subsequent echocardiogram normal, ~ 20% occlusion in carotid arteries.
    General medical - borderline anemia, high cholesterol (Lipitor taken for about a year, stopped 10/02 due to Dad's bout with severe myositis).

Thanks for any insight/advice.

[CCF-M.D.-RCJ]

Bobolinkx,

Thanks for the post.

Not to be too simplistic, but it sounds as if you are becoming dehydrated.  Dehydration is the most common reason for orthostatic hypotension, and the most often overlooked.  Try adding extra fluid intake to your work routine, and talk to your doctor.

Hope that helps.