Feeling Drained After Using the Restroom? It Could Be Your Vagus Nerve.
New Brunswick,NJ – That post-poop fatigue is a surprisingly common experience with a physiological explanation,experts say. Straining during a bowel movement can trigger a response in the vagus nerve, possibly leading to lightheadedness, tiredness, and even fainting.
Ellen M. stein, MD, associate professor of medicine in the division of gastroenterology and hepatology at Rutgers Medical School, explains the vagus nerve is a key component of the parasympathetic nervous system, responsible for regulating vital functions like digestion, heart rate, and immune response.
“Straining really hard during a bowel movement can activate the vagus [nerve],” Dr. Stein says. This activation, for some individuals, can slow heart rate and lower blood pressure, resulting in a condition called vasovagal syncope. Symptoms include sudden lightheadedness and fatigue.
Rudolph Bedford, MD, a gastroenterologist at Providence Saint John’s Health Center in Santa Monica, California, elaborates on the mechanics. “If you’re straining or pushing hard,your stomach muscles are contracting,and that will decrease blood flow into the vagus nerve,” he explains.”That can make you feel dizzy when you get up after a bowel movement, or tired. Some people will even faint or lose consciousness if they’re straining enough.”
Dr. stein adds that holding your breath while straining can also contribute to feelings of weakness afterward.
