Why Do Muscles Get Sore Several Hours or Days After Working Out?

If you have ever exercised, then chances are you have experienced “delayed onset muscle soreness,” or DOMS.

DOMS is a phenomenon that describes muscle discomfort and stiffness that occurs 12 to 24 hours after exercise, with the most severe discomfort occurring 24 to 72 hours following exercise. DOMS is most frequently felt when someone begins a new exercise program or changes the components of their existing exercise routine, such as intensity, volume or exercise selection.

There is a large misconception about DOMS: many individuals believe it is due to lactic acid buildup in the muscle, when it actually has to do with many small microscopic tears of the muscle fibers. Muscles go through a tremendous amount of physical stress while exercising, and those tiny tears are a natural response. It is during the healing process of these tears that our muscles are actually growing (muscle hypertrophy).

Research has shown that it is primarily the eccentric phase of a muscle contraction that causes the majority of the tears, resulting in DOMS. The eccentric phase is when the muscle is returning to its original length. Some examples of an eccentric muscle contraction are the lowering phase of a bicep curl, or slowly lowering yourself toward the ground during a push-up. It is important to understand DOMS is not pain during exercise.

No one should ever exercise through pain. Any pain that occurs during exercise typically means something is wrong and you should stop immediately. The “no pain, no gain” mantra so many grew up with is false and could cause a person to become seriously injured. Exercise should be challenging, not painful. Many times, pain is a clue that your form is poor or that the amount of weight being used is too much.

Unfortunately, there is nothing that can be done to completely prevent DOMS, but there are ways to minimize the effects. First, always make sure you warm up prior to exercising. A typical warm-up should last approximately five to ten minutes. The heart rate should be elevated with signs of perspiration. By increasing blood flow and heat to the muscles, they are more pliable and resilient.

Increase the intensity or duration of your workouts slowly. Increasing too quickly can lead to muscle discomfort and injury. Always go through a cool down once you have completed your exercise session. Stretching and using a foam roller are excellent ways to end your workout. Ice packs, massage, and oral pain relief can be used to help ease DOMS. A light workout such as a long walk following an intense workout session has also been shown to help decrease the amount of time a person experiences DOMS.

Typically, DOMS lasts anywhere from 3 to 5 days, but may last longer depending on the person and the intensity of the exercises performed. When all is said and done, a person who pushes themselves in a healthy and safe way during a workout is going to experience some level of DOMS. This is a normal response, representing the hard work that was achieved.

It’s also a sign to take a rest from using those same muscle groups over the next day or two. Rest days are critical for repair and muscle growth, so enjoy them.

— Jennifer Oestreich is manager of the Wellness Center at Mariners Hospital.

Tags: exercise, strength training