MetCon addiction is real, and chances are it's in a gym near you.
Metabolic Conditioning. A potent, potent thing, deserving of respect and responsibility. Which means abuse and misuse are rampant.
See, one thing people get a taste of when they are new to CrossFit is that feeling of being flattened from a workout. Usually in 20 minutes or less. There are even t-shirts made to brag this point. At home, in the park, at a Globo Gym, and especially in a CrossFit affiliate with a group of fellow sufferers-- the addiction can start immediately. It's an experience all its own, that's for sure. That feeling after a tough conditioning workout: dumb, dizzy, defeated... WOD drunk. And like being drunk, or high, or in love, or on a thrill-seeking adrenaline rush, the MetCon experience can be dangerous.
This is why we can't have nice things.
The human brain receives neural pathway stimuli from many sources in life, so it's not ridiculous to see something like this happen with physical fitness. Consistent exercise causes the body to produce endorphins, which are hormones secreted by your pituitary gland to block pain, decrease anxiety and create feelings of happiness. But oxidative stress, like that from aerobic cardiovascular training, also causes the hormone cortisol to be released. This is fine, but not in high levels.
There is research to suggest oxidative training and its effects can cause body cells to age prematurely. [1, 2, 3] The biggest contention is that aerobic training raises cortisol levels, which accelerates aging because it increases inflammation in the brain, heart, intestinal tract, and reproductive organs. If your cortisol levels are chronically elevated, your body may store fat instead of burning it, adding more stress to the organs and body systems.
Which means cardio is a killer. Almost literally.
Of course the opposite would be to never endure sustained physical work in your life... and we know that's by far more dangerous, and immediately so. There is of course plenty of research suggesting the opposite from above-- that aerobic activity is a must and even in excessive use it can train the body to deal with the rigor of workouts (or life), becoming more resistant to stress of the future. [1, 2, 3, 4]
Which means not doing cardio is a killer. Confused yet?
This brings us to the point: it's the type of metabolic conditioning you use and the frequency at which you use it that matter.
The related memes that have circulated for a few years are those that portray endurance athletes without the musculature of strength or speed training. Although this is arguable and it isn't very fair to pit one person's body against another's, as the saying goes, the proof is in the pudding. Trying out different workout regimens ourselves, we can come to our own conclusions about body composition and make comparisons to the former "us." Ultimately it is me vs. me, you vs. you in this whole fitness endeavor after all. Being in CrossFit has it ingrained that all cardio and no strength training is not the path towards general and overall fitness across a broad spectrum. Constantly varied, functional movements performed at high intensity in order to increase work capacity over broad time and modal domains.
Yet, if we look at intense MetCon use in a CrossFit program we can still find the overtrained athlete. CrossFit's "mascots" even include Pukie the Clown and Uncle Rhabdo... what kind of message is that? If you haven't checked the scares of Rhabdomyolysis, Google search and/or see the Journal Article here.
So let's take a typical new CrossFitter-- all gung-ho and ready with new shoes, new apparel, and a new vocabulary-- on a binge of being WODrunk in public 3 days in a row. Having that feeling of being demolished by the longer, arduous (and usually named) MetCons can be a gateway for the belief that the only way to "get good" in CrossFit is to ruin yourself daily. As the addiction begins, this MetCon abuse can in fact lead to something very similar to the above pic. Neglecting strength work or shrugging off variance in CrossFit WODs, energy pathways included, is directly at odds with the program protocol itself. But in combination with lack of recovery days, said newbie has now set up a potentially lethal habit. Not to mention mental health experts warn that in the exercise addict we see brain activity and thought processes similar to that with eating disorders and drug addiction. Scary.
This, ladies and gentlemen, is what I'm taking the time to warn you about.
BUT... high volume training is not the same as overtraining. Let's make that clear. So if you train smart by providing enough stimulus for progress, but not so much that you overtrain, any oxidative stress from your training will not damage your health but instead will help your gains on the road to fitness. Especially if you keep your MetCons relatively short and sweet. Okay, at least short(er).
CrossFit is addictive, in the best way. But funny enough it walks a fine line with an unhealthy obsession. MetCons especially. So check yourself. Know when to lay off the MetCon pedal. And if you happen upon an addict laying in a sweat angel for the umpteenth day in a row, speaking in tongues of rounds and reps after succumbing to the lure of another high rep WOD, give them warning. But don't pass judgement. They're difficult to spot, you see-- they look just like you and me. Which makes it hard to know whether to give them a sweaty pat on the back, or to tell them to take a rest day.