Strength training is great. No other activity has such a profound impact on bone health and body composition. You can run for hours on the treadmill every week and go to every Zumba class at your local gym, it’s not going to give you a strong, muscular body. You need to lift something as well, push heavy objects, or otherwise apply some resistance to your muscles. If you don’t, the glutes, biceps, hamstrings, and all of the other muscles that make up your physical self have no reason to expand and grow stronger, but may instead atrophy. Also, your bones may gradually deteriorate, becoming prone to fractures. When you hit the sweet spot in terms of intensity and volume and train with good technique, strength training is highly beneficial; however, if you fail to hit this sweet spot and end up doing too much, too often, your health may suffer.
Is excessive strength training as bad as excessive cardiovascular exercise?
If you’ve been reading about fitness and exercise on one or more of the many ancestral health blogs that are out there, you’ve undoubtedly come across the term chronic cardio. This term is used to describe prolonged, high-intensity cardiovascular exercise; a type of training that may adversely affect health and longevity.
What you probably haven’t read about though is the adverse effects associated with excessive strength training. Very few bloggers, health practitioners, or scientists talk about this issue. If you do a google search on strength training, most of the articles that pop up focus on the numerous beneficial health effects associated with regular resistance exercise.
You have to look long and hard to find a blog post or scientific paper that covers the possible dangers of strength training. This is unfortunate, because the fact is that when taken to the extreme, strength training can have a range of detrimental health effects. I should know, as I did heavy bodybuilding-type training for many years. Instead of making my body healthier it contributed to tearing down my immune system and making me ill.
I didn’t experience the problems I did because I lifted with poor technique or didn’t eat enough; rather, my body didn’t function optimally because I did too much resistance exercise, too often. This downward spiral began a little over a decade ago, as I started getting “obsessed” with strength training. I trained multiple times every week, did almost every set to failure, blasted each muscle group once or twice a week, and rarely left the gym with much energy left in the tank.
In retrospect I obviously see that this type of program is anything but balanced, but back then, I didn’t recognize the inherent problems with my high-volume, high-intensity workouts. Most fitness competitors, bodybuilders, and even average Joes at the gym seemed to follow this type of approach, so why shouldn’t I? I just wanted to get big and strong. I also wanted to be healthy; but the problem was that I thought my heavy training regime was enhancing my health, while in reality, it was actually undermining it.
It wasn’t until after many years of adhering to this type of bodybuilding-style program that I finally realised that the way I was doing things wasn’t working for me. Today, I still work out, but not like before. I don’t split the body into separate muscle groups and hit the major ones with 20 sets once a week and the smaller ones with 10-15; I don’t do every set to failure; I don’t strive to do as many sets and repetitions as possible; and, perhaps most importantly, I’m no longer obsessed with getting as strong and big as possible.
Too much of a good thing can be a bad thing
When faced with a dilemma related to nutrition or health – or anything else in life for that matter – I always start by looking at the issue from the perspective of an evolutionary biologist. When we stress our bodies in evolutionarily novel ways, adverse health effects tend to occur. These novel stimuli can be categorized into three categories: Too new, too much, and too little. Excessive strength training fits into two categories: Too much and too new.
Our ancient forebears were very physically active, but they obviously never performed heavy squats, deadlifts, and other similar exercises that many runners, sprinters, weight lifters, and fitness enthusiasts do today. That doesn’t mean that we shouldn’t be doing these types of exercises; however, it does imply that we should be a little cautious about how much and what types of strength training we do.
Heavy resistance exercise puts a lot of strain on the body. Our musculoskeletal systems are very adaptable, in the sense that our muscles and bones get stronger when they are stressed, something that ensures that the body is better able to perform similar activities in the future. That said, there is a limit to how much stress we can put on our bodies before they malfunction. I would argue that many gym goers who adhere to a bodybuilding-type training program, in particular those who do virtually every set to failure and completely destroy each muscle group once or twice a week, are pushing their bodies past this limit.
A lot of strength trainees and bodybuilders consume massive amounts of food and take a wide range of supplements in an attempt to gain as much muscle as possible. Many consume more than they need to stay in energy balance and thereby gain a good amount of fat as well as muscle. This very high intake of food and supplements such as creatine and whey protein can put a lot of stress on the gastrointestinal system, alter the microbiome, and increase the absorption of lipopolysaccharides and other nasty substances into systemic circulation.
While a very healthy individual with a well-functioning immune system and healthy gut may be equipped to deal with these stressors, a person with a damaged system may not do so well when faced with these stimuli. Few, if any, people in contemporary industrialized societies are truly healthy, so there’s definitely some room for concern here. We have all been exposed to processed foods, drugs, and environmental pollutants, and many, if not most, people have elevated levels of inflammatory biomarkers such as interleukin-6 circulating in their blood.
Combine a poorly designed bodybuilding-type training program with a high intake of supplements and calories and/or a degraded microbiota and immune system, and you got a recipe for disaster.
The harmful effects of overtraining
What actually happens in our bodies when we exercise too much? In the past section I described my own personal experience with excessive strength training, but I didn’t get into the actual science on the topic.
The few studies have looked into the possible harmful effects of strength training have primarily focused on physical injuries. Not surprisingly, weight training, when performed with poor technique, is associated with an increased risk of neck and knee pain, back injuries, and other similar conditions that affect the muscles and bones (1, 2). Sometimes, these conditions become chronic and significantly impact the health and well-being of the affected person.
Less attention has been given to other adverse health effects that may occur as a result of excessive strength training; however, that doesn’t mean that there aren’t any. There’s no reason to think that excessive strength training isn’t just as bad as excessive cardiovascular exercise.
Dozens of studies have found that prolonged, high-intensity endurance training, performed on a very frequent basis, may adversely affect cardiovascular health, compromise the body’s protection against infections, and cause adrenal insufficiency, leaky gut, and gastrointestinal distress (3, 4, 5). I strongly believe that many of the same problems can occur as a result of excessive strength training, a statement that is supported by research showing that the neuroendocrine responses that accompany resistance exercise overtraining appear to be somewhat similar to those that occur as a result of excessive aerobic training (6).
Here’s what a 2013 reviw paper entitled Overtraining, Exercise, and Adrenal Insufficiency had to say about this issue:
Overtraining Syndrome (OS) has been described as chronic fatigue, burnout and staleness, where an imbalance between training/competition, versus recovery occurs. Training alone is seldom the primary cause. In most cases, the total amount of stress on the athlete exceeds their capacity to cope. A triggering stressful event, along with the chronic overtraining, pushes the athlete to start developing symptoms of overtraining syndrome, which is far worse than classic overtraining. Overtraining can be a part of healthy training, if only done for a short period of time. Chronic overtraining is what leads to serious health problems, including adrenal insufficiency. (3)
Strength training is an essential component of a well-balanced fitness program. Everyone who can should do some type of resistance exercise on a regular basis. The problem most people have isn’t that they do too much strength training, but rather that they do too little. However, the opposite can be said for some bodybuilders, fitness competitors, and other gym junkies.
The human body may be ill-equipped to deal with the stimuli that are produced by a high-volume, high-intensity bodybuilding-type workout. This type of exercise pattern differs markedly from the physical activity pattern(s) that conditioned the human genetic make-up.
Excessive strength training may cause a wide range of adverse health effects, including adrenal insufficiency, chronic injuries, gastrointestinal distress, and immune dysfunction. This is particularly true if it’s coupled with a compromised immune system and/or a high intake of supplements and unhealthy foods.
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