How inflammation plays a hand in exercise and recovery
If you’re someone who gets outside, goes to the gym, or chases around your kids, you’ve probably injured yourself at some point, and are familiar with general inflammation at the site of injury.
The reasoning for this is quite simple: traumatic injury to tissues, like when you scrape your elbow, generates a self-healing process to reduce the amount of blood loss and fend off foreign bodies that may enter through this open wound.
To do this, the damaged and surrounding cells release signals that trigger local immune cells to increase their activity and secrete special immune proteins that recruit other immune cells to the injury site. The local accumulation of inflammatory biomolecules and immune cells can cause warmth and redness at the site of injury and contribute to swelling.
We’ve discussed inflammation before – but today we’re talking specifics as it pertains to staying fit!
As much as you want to return to lift those weights or go for another run, just know that regular rest is just as important as regular exercise.
It’s important to know, inflammation is categorized by its duration. Acute inflammation, for example, is generated by tissue damage and may last for a few days. Sub-acute inflammation, which may be caused by severe tissue damage or infection, can last upwards of 6 weeks. On the other hand, chronic inflammation may last for months to years and is typically associated with an abnormal immune system and/or chronic disease. The etiology of chronic inflammation is quite complex, but generally involves a failure by the body to eliminate or adequately repair the injury.
Are inflammation and cellular health linked?
Your cells are the basic units of life; humans are made up of approximately 30 trillion cells, each with complex internal structures called organelles that function to aid in survival and regulate cellular processes. In your body, these cells differentiate to become specialized in a variety of function that make of human tissues and organs.
When you experience an injury, your cells secrete chemicals that start the inflammation process, these messengers are commonly known as hormones (regulated by the endocrine system) as well as special proteins called cytokines. Both hormones and cytokines play a role in regulating the inflammation process and their disruption can often lead to a failure for your body to properly heal the injury. For example, one important hormone, cortisol, is released from your adrenal glands to reduce inflammation and when this hormone is too high or too low the bodies’ ability to treat the injury becomes compromised.
Does exercise influence inflammation?
It’s easy to think inflammation is all reactionary, or just something “bad” that happens as you age. However, one of the most effective ways you can promote health is to exercise, which can actually cause tissue inflammation as well!
In fact, one of the first things you may notice after a good workout is that your muscles feel tender, sore, and stiff, often referred to as exercise-induced muscle damage and/or delayed onset muscle soreness. This soreness is due to mechanical stress on muscle fibres, which causes them to stretch and tear, ultimately causing local inflammatory responses.
Increased metabolic activity of the muscles actually puts stress on the supply and demand of energy resources, often depleting resources below the limit of supply. In these situations, energetic stress can cause inflammation locally, within and around the muscle tissues, generating cytokines and reactive oxygen species (the dreaded oxidative stress) in the process.
Despite this, exercise-induced inflammation is absolutely necessary as it promotes healing of the muscle fibers. Regular physical training promotes long-lasting anti-inflammatory actions, because short-term inflammation increases in pro-inflammatory messengers. These messengers can generate long-term adaptive responses to exercise stress, meaning your body is more adaptable and can bounce back faster.
There is also research that have found moderate-intensity exercise promotes more general anti-inflammatory responses that can aid treatment of various chronic conditions, such as diabetes, obesity, and mood disorders. Just another reason mild inflammation from exercise is actually beneficial!
As with anything, it’s important to exercise in moderation, because overexertion can amplify the acute inflammatory response beyond levels that can be adequately regulated by anti-inflammatory processes short-term. This can lead to overstretching of muscle fibers and/or make you susceptible to injury, further contributing to increased, long-term inflammation.
Does age influence the relationship between exercise and inflammation?
Aging is associated with chronic low-grade inflammation; as we get older, the risk of disease, injury, and mortality increases. Think of it as general wear and tear – everything we’ve done up to this point in our lives contributing in some way to our low-grade inflammation levels.
In fact, there is a 2-4x increase in the general levels of inflammatory cytokines, even when no other health conditions exist. This general increase in inflammation may be a key factor in the development of age-related disease like obesity, cardiovascular disease, and neurodegenerative disorders like Alzheimer’s disease.
Exercise is a great way to promote the growth of muscle tissues, which can help combat age-related frailty. Keeping your body moving in older age also decreases general circulating levels of inflammatory cytokines and increases anti-inflammatory cytokines, thereby promoting a healthy immune response. Because the number of muscle fibers tend to decline as we age, it is important to keep our immune systems in check; systemic inflammation can amplify the rate by which muscle fibers dissipate over time.
How important is muscle recovery as it relates to inflammation?
If you’re an active person, you probably know the “post-workout” well. The post-workout recovery is the period of time following aerobic exercise where muscle fatigue and soreness dissipate slowly. You’re no longer feeling the stress of the workout, but your body is entering recovery. It’s a crucial period where muscle cells are given the opportunity to re-establish energy resources, which helps resolve local inflammation.
So, as much as you want to return to lift those weights or go for another run, just know that regular rest is just as important as regular exercise. Without allowing your body to naturally combat the inflammation, you run the risk of overexertion, injury and long-term health complications.
As discussed in the above sections, the total number of inflammatory chemicals increase as we get older, this is considered a normal and natural process commonly referred to as low-grade chronic inflammation or ‘inflammaging’.
The resting level of inflammatory chemicals are much higher in people who maintain sedentary lifestyles and consume pro-inflammatory diets compared to their more active and healthier counterparts. In fact, regular resistance training has been shown to reduce muscle loss and risk of injury in the elderly, showing that regular exercise is preventative and important!
The key here is to maintain consistent exercise with adequate rest throughout your lifetime, and if done right, you’ll be running, laughing, and living a healthy life well into your retirement years!