Physical Therapy Expert Melissa Prestipino, DPT: Sore Muscles after Exercising

I just exercised two days ago but when I woke up today my muscles are really throbbing. Why is this happening?

According to the ACSM (American College of Sports Medicine), any type of activity that places unaccustomed loads on muscle may lead to “delayed onset muscle soreness” (DOMS). This type of soreness is different from acute soreness, which is pain that develops during the actual activity. As the ACSM clarifies, “delayed soreness typically begins to develop 12-24 hours after the exercise has been performed and may produce the greatest pain between 24-72 hours after the exercise has been performed.” Everyone is able to develop DOMS, including people that have exercised for several years.