Why Does My Body Ache After Exercise?

Woman stretching in forest

That stiff, achy feeling you get in the days after exercise is a normal physiological response known as delayed onset muscle soreness. You can take it as a positive sign that your muscles have felt the workout, but the pain may also turn you off to further exercise. There are ways to get in an equally effective workout sans pain.

The Underlying Cause

Exercise physiologists once believed that the buildup of lactic acid contributed to delayed onset muscle soreness. However, they now know that lactic acid is gone before soreness sets in. Body aches are most likely caused by tiny tears in the fibers of worked muscles as well as muscle spasms and, in some cases, overstretching of muscles.

Risk Factors

You are more likely to develop delayed onset muscle soreness if you are new to working out, if you’ve gone a long time without exercising and start up again, if you have picked up a new type of physical activity or if you have recently boosted the intensity, length or frequency of your exercise sessions. You are also more likely to develop soreness if your exercise sessions are rich in eccentric muscle contractions, which occur during actions such as lowering a weight back down after a bicep curl.

Getting Through It

Because no medication can treat delayed onset muscle soreness, time is the greatest healer of exercise-induced muscle aches. You may begin to experience soreness within 24 to 48 hours of your workout and it should begin diminishing by 72 hours past your workout. Rather than letting the discomfort take over, take some steps to reduce it as your muscles recover. Using an ice or heat pack on affected areas may be soothing, as may massage therapy, gentle stretching and non-steroidal anti-inflammatory drugs such as ibuprofen.


Whether you’re an inexperienced exerciser or an avid athlete, keeping “slow and steady” in mind will help you reduce post-exercise muscle soreness. For instance, begin weight training using lighter weights two to three times per week and slowly build up the intensity, frequency and duration by 10 percent per week as you get stronger. The same method should apply if you can easily run three miles but are new to kickboxing. Also, no matter how experienced you are at your activity of choice, warming up for five to 10 minutes beforehand and gently stretching your muscles afterward can help reduce your risk of pain in the days that follow. If you continue to experience pain, observe how often you perform eccentric muscle contractions. If you often run downhill or lift heavy weights, for example, you may need to alternate between your go-to activity and activities that don’t produce as many eccentric contractions.