The stress placed on your metabolic and musculoskeletal systems when you’re exercising can lead to muscle aches after your workout is finished. The more intense and stressful your workout, the more likely you are to experience soreness. When you feel discomfort right after you exercise, this is referred to as acute muscle soreness. The achiness that pops up a day after your workout and lasts for a few days is referred to as delayed onset muscle soreness, or DOMS.
Acute Muscle Soreness
The achiness that you experience immediately after you’ve finished exercising is considered acute soreness, which means that it lasts only for a short duration. The discomfort often feels like a burning sensation and is accompanied by muscle fatigue. It typically occurs after particularly strenuous anaerobic exercise, like sprints or weight training while using heavy weights, and it usually subsides after a few minutes.
Causes of Acute Pain
Acute muscle soreness can be caused by temporary ischemia, which is a restriction of blood supply to your working tissues, and the accumulation of metabolic waste products. A lack of blood supply means that your tissues become starved of oxygen and are unable to get rid of carbon dioxide, a metabolic waste product. This lack of blood supply, along with the participation in strenuous exercise, can cause an accumulation of other metabolic waste products, like hydrogen ions and lactate from lactic acid, which cause a burning sensation.
Delayed Onset Muscle Soreness
DOMS is the muscle discomfort that occurs 24 to 72 hours after you’ve finished a workout. DOMS most commonly follows workouts that involve eccentric activities, like jumping, hill running and step aerobics, which force your muscles to lengthen as force is applied. For example, walking or jogging downhill requires your quads, glutes and calves to lengthen as they control your descent and will likely result in DOMS. A weight-training exercise like deadlifts, where your glutes, quads and hamstrings contract while lengthening as you lower the bar to the floor, is an eccentric exercise that often causes delayed-onset soreness. DOMS also typically follows high-volume weight-training workouts that feature a high number of sets and reps.
Causes of DOMS
The reason eccentric and high-volume exercise leads to DOMS is because it causes microscopic damage to your muscle tissues. This tissue trauma stimulates an inflammatory response, which in turn leads to metabolic waste products forming and causing a chemical stimulus to nerve endings, resulting in pain. Swelling, which results as part of the healing process, can also put stress on the nerve endings and add to discomfort.