Q I’ve been an endurance athlete for over five years. For a while now, if I stand up fast after sitting I feel lightheaded. Nothing that has caused me to faint or blackout, but I have to pause. I have no shortness of breath or rapid heartbeat, just a seeming drop in my blood pressure. It is especially intense after a moderate-to-strenuous workout. I have normal to slightly low BP, no history of heart disease in my family, low cholesterol and I visit my doctor regularly. What could be causing this? Should I be concerned? – ED
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A This is a common problem in endurance-trained runners and occurs with change in posture from lying, squatting, or sitting to standing. The medical term is orthostatic or postural hypotension that causes delayed blood flow to the brain causing the lightheadedness. The usual symptoms are feeling lightheaded or dizzy after standing up, but lightheadedness can be accompanied by blurry vision, weakness, nausea, confusion, or actual fainting (also called syncope). The symptoms that occur are going to be accentuated by a strenuous workout that leaves your blood vessels extra dilated, and this is the most common cause of exercise associated collapse that we see at the end of running races.
Orthostatic changes occur as blood pools in your legs as you move to standing and a majority of your blood volume is below your heart. If you are endurance trained, the vessels in your legs are dilated, your heart rate is low, and the response to pump blood back to your heart and up to your brain is delayed just enough to deprive the tissue of oxygen leaving you temporarily dizzy. The condition is not a concern as long as you are aware it can happen and it clears quickly. It may require that you take a few moments to let your body “equilibrate” before you walk away after you stand.
For people on medications that affect peripheral blood flow, like most blood pressure medications, the lightheadedness can progress to fainting leading to falls to the ground and associated problems like head trauma and hip fractures. It is critical for runners on medications with these symptoms to discuss them with their physician.
So for you, take the symptoms into account when you stand up. Take enough time when you stand to feel “normal” before you begin to walk away.
