The Impact of Strength Training and Inflammation
Many of us have become aware of the negative effects of inflammation. It’s the reason why omega-3 fatty acid supplements have become popular in recent years. It’s one of the major reasons why we floss. It’s a big detriment of smoking. It’s the target of medications taken for arthritis, headaches, and menstrual pain. Inflammation is one of the major players in the development of heart disease (some medical professionals think it’s the primary cause). It’s a sign of atherosclerosis and type 2 diabetes developments. The list goes on and on.
We use the term “inflammation” often, but what exactly is inflammation? Inflammation is a sign that the body is trying to heal itself. When inflamed, our bodies are trying to remove or destroy an unwanted presence, such as foreign bacteria, or we are repairing damaged tissue. Signs are swelling, redness, heat, and pain.
Inflammation can be acute or chronic, and the difference is critical. Examples of acute scenarios are sore throats, cuts on our skin, and an ingrown toenail. Acute inflammation is immediate but lasts for a few days or weeks. Chronic inflammation, on the other hand, is a major issue. This occurs when an acute situation lingers, an autoimmune problem exists, or when there is some other chronic irritant. Chronic is the type found with heart disease and type 2 diabetes.
We measure inflammation by looking at cytokines. Cytokines are proteins that influence the survival and proliferation of immune cells. They also have a key role in initiating the inflammatory response. Some cytokines are anti-inflammatory and some are pro-inflammatory. Also, C-reactive protein (CRP) is another substance produced by the liver that indicates systemic inflammation. Chronic inflammation is considered as a sustained two-to-three fold increase in some cytokines and CRP.
Flossing, omega-3 fatty acid intake, and low-intensity physical activity help decrease systemic inflammation. However, strength training’s impact on inflammation isn’t as well known. Thankfully, researchers at the University of Connecticut recently analyzed the few studies that do exist on the relationship between the two .
The researchers found a variety of results with strength training and inflammation. Microscopic muscle damage occurs during strength training, especially during the lowering phase of a repetition. As a result of workout-induced muscle damage, inflammation rises in the short term, and the production of several cytokines increases (although not all are pro-inflammatory). As a whole, the cytokines released right after strength training have two major responsibilities: repair the muscle damage and regulate new muscle growth. Both are positive responses.
Fortunately, strength training also actually improves chronic inflammation. A 12-month study using strength training with overweight women averaging 39 years old showed a decrease in CRP. A nine-week study featuring young men and women training with heavier weight loads caused a decrease in one pro-inflammatory cytokine. Strength training also improved CRP in a three-month study with old and young populations. These were just some of the positive results reported by the University of Connecticut researchers.
The researchers did note that intensity was a key factor. A seven-week study of young men showed that heavy resistance strength training improved two anti-inflammatory cytokines to a greater extent than lighter weight strength training. Another important factor was rest. According to one study, when adequate rest isn’t achieved, exercise can be pro-inflammatory.
What is the mechanism causing strength training to benefit chronic inflammation? The researchers stated that muscle gained from strength training increases the body’s daily energy expenditure (metabolism) and insulin sensitivity (a state key to preventing diabetes), and both of those results decrease the requirement for pro-inflammatory cytokines and CRP.
Overall, strength training increases some acute inflammation markers, but those markers lead to long term health benefits. Therefore, strength training’s positive effects on chronic inflammation are probably part of why it is shown to decrease the risk of heart disease and diabetes. To maximize your health gains, train with challenging weights and get adequate rest between your workouts.
1. Calle, M. C., & Fernandez, M. L. (2010). Effects of resistance training on the inflammatory response. Nutrition research and practice, 4(4), 259-269.