Have you ever experienced soreness in your muscles a day or two days after working out? 

It may hurt, feel stiff, or uncomfortable to use, stretch, or even touch the affected muscles.

This sensation is what we call Delayed Onset Muscle Soreness (or DOMS). It’s part of your body’s natural response to new movements and exercises, and it can be a real pain in the rear…

Literally.

So, what’s going on in our bodies exactly? And should you be worried?

You may have heard people attribute DOMS to lactic acid build-up in the muscles—however this is a common mistake. Lactic acid build-up is responsible for the short-term “burn” and soreness you feel during a high-intensity exercise. You feel it when your body is using the anaerobic lactic acid system to supply energy to your muscles in the absence of oxygen.

The type of soreness you feel days after you workout is an entirely different system. It’s actually an immune system response, and is similar to the healing process you feel when you are injured or sick.

That’s because when you do a hard workout and stress your muscles, it creates microscopic tears in the muscle fibers. Your body reads these as injuries, and goes into an inflamed state to heal and fortify those areas. It’s during that healing process that your body builds more muscle and you get stronger, allowing you to handle the same workout intensity next time without receiving as much damage to the muscles.

In the 24 to 48 hours following an intense workout, your body responds in what is called an “inflammatory cascade.” The damaged muscles get a slow flood of increased blood flow, hormones, proteins, and cellular fluid. By the second day after your intense workout, all the parts have arrived in your muscles and can begin to work—but their presence creates pressure on your tissues and irritates nerves, which causes the pain.[1, 2, 3]

Should you be worried?

In most cases of DOMS, the soreness is temporary and goes away within a day or so. Sometimes—especially at the start of a new program—DOMS can last several days. 

You can alleviate soreness by moving around, stretching, or performing some self-myofascial release with a foam roller, lacrosse ball, theracane, or similar device.

Just remember that the longer you sit still, the more you’ll notice the soreness when you get moving again. Try to stay active to prevent the stiffness from setting in!

If the soreness is too intense—meaning you feel your muscles throbbing or even wake up in the middle of the night in pain—it could be a sign that you are overreaching in your workouts and need to bring down the intensity.

If the soreness is more than you can bear, you can try applying ice on the sore muscles for ten minutes at a time to reduce inflammation. Some people also take inflammation reducing drugs like ibuprofen, but check with your doctor first before taking anything (even over the counter). 

You should definitely see a doctor if your soreness lasts more than a few days and isn’t getting better—this may be a sign that there is more than just DOMS going on!

Sign Up for Personal Training!

If you’d like additional guidance on training, submit a consultation form and I’ll help you create a plan of action to reach your goals. I offer online, one-on-one, and semi-private personal training and health coaching to individuals, couples, and groups. Click on the button below to get started.

Footnotes:

[1] Blair Callaghan, P.T., D.P.T., quoted in “What Is Delayed-Onset Muscle Soreness (DOMS)?“ By Danielle Zickl. Men’s Health https://www.menshealth.com/fitness/a19542200/what-is-delayed-onset-muscle-soreness

[2] InformedHealth.org. “What is an inflammation?“ IQWiG (Institute for Quality and Efficiency in Health Care). https://www.ncbi.nlm.nih.gov/books/NBK279298/

[3] Jun-Ming Zhang, MSc, MD1 and Jianxiong An, MSc, MD2, “Cytokines, Inflammation and Pain,” Int Anesthesiol Clin. 2007 Spring; 45(2): 27–37. Accessible at: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2785020/

About the Author

Jayd Harrison is a personal trainer and content creator. She helps people to build muscle, burn fat, and clean up their diets with her online coaching programs and social media content. Check out some of Jayd’s coaching videos on Youtube, or join Jayd live on Twitch and follow on social media.