I feel dizzy when I stand up.

[St1243]

Well this has been happening to me only for a few(4-5) days. Sometimes during the day when I stand up after lying down I feel dizzy , by which I mean light-headed.
Also, it has been a month since I have been dieting and exercising rigorously and my diet is now 1/4th of what it was. Furthermore, I have lost 15lbs in the last month. So is this some sort of deficiency or is it something serious.

What should I do?

[Ger57]

Did you check your blood pressure? Besides dehydration, exercising and loss of weight often causes a decrease in blood pressure even if you keep yourself hydrated.
Low bp would be apparent the most when you stand up. The supply of blood to your brain is then a little lower which gives dizzyness or lightheadedness.

In many instances, low blood pressure isn't serious. If you have consistently low readings but feel fine, your doctor is likely to monitor you during routine exams.

Even occasional dizziness or lightheadedness may be a relatively minor problem — the result of mild dehydration from too much time in the sun or a hot tub, for example. In these situations, it's not a matter so much of how far, but of how quickly, your blood pressure drops.

Still, it's important to see your doctor if you experience any signs or symptoms of hypotension because they sometimes can point to more-serious problems. It can be helpful to keep a record of your symptoms, when they occur and what you were doing at the time.

[rpwoodard]

BTW, I felt significantly better after I increased my daily water intake based on a guideline a cardiologist recommended:
- start with the number of pounds you weigh (ex: 150)
- divide that in half--> 75
--You should drink 75 oz of water daily.

Electrolytes weren't essential...plain filtered water was sufficient. However...sometimes when I exercise and/or perspire a lot (as you are) I buy water with electrolytes added and my body LOVES this water!  It quenches my thirst in ways regular water cannot.

I don't tolerate Gatorade well because of the sugar.
For my family, I've bought the electrolyte packets or fizz tablets that caregiver mentioned.
rpw

[caregiver222]

Water won't do it. You need electyrolytes, such as those from Gatorade.

There is a wild card. Dieting sometimes causes low blood sugar, which is a contributing factor,.

[rpwoodard]

Hi there, how much water do you drink each day? I have a daughter --when she was your age, she drank maybe 32 oz of water daily. That's not nearly enough. Now that she is 19, she drinks a lot more.  

When she was under-hydrated, she experienced some of the symptoms you mentioned in your post earlier this year.

I'm not a physician, not making recommendations...just describing my experiences.

Good luck to you...
rpw

[caregiver222]

The most likely etiology is simple dehydration, and the solution is to drink electrolytes. Gatoraid, pediatrol or get an electrolyte packet to mix with water from the drug store.

One simple method to test for dehydration is to take what are called orthostatic vital signs. Do a google search.

Other contributing causes are anemia (of which there are a baker's dozen types), so blood work might be in order, to include a hematocrit.

Sometimes there is a failure of the vasculature in the legs to contract appropriately when changing position. This happens with certain neurological disorders and is highly unlikely.