Q. I am a healthy 52 year old who likes to stay fit. Recently, I have occasionally fainted after doing eight or 10 chin-ups. My physician did an EKG and stress test the first time this happened and found my heart is normal. He had me wear a monitor for 24 hours, and it indicated nothing was wrong. Your thoughts?
A. Someone who faints during exercise can have a serious life-threatening issue, such as narrowing of a heart valve, thickening of heart muscle (cardiomyopathy), or life-threatening arrhythmias. In your case, the chances of having a serious condition are pretty low, given the negative results of your tests.
You may not be breathing during your chin-ups, and straining raises the pressure in your chest and prevents blood from returning to the heart. This causes your heart’s output to drop (little blood in, little blood out) and your blood pressure to fall. The solution is to remember to breathe in and out as you do your chin-ups.
— Thomas Lee, M.D. and Richard Lee, M.D.
Co-Editors in Chief, Harvard Heart Letter