Guest writer: Lauren Shorser. Connect with her on LinkedIn.
Lies, lies, lies, it’s all lies. The Internet is full of myths and misinformation about fitness and nutrition. One of the most pervasive fitness myths is that aerobic or cardiovascular exercise, like jogging, can cause muscle loss. This is nonsense, for the vast majority of athletes of all levels.
But like any good story, this claim has a kernel of truth to it. Three factors have contributed to this preposterous fallacy.
1. Aerobic workouts send a different message to our muscles than resistance workouts do. Aerobic workouts try to tell your muscles that what we really need is endurance. We need the muscles to be able to work for a long time. Resistance workouts focus on getting our muscles to work as hard as they can, for a short amount of time. Doing both can confuse our bodies, slowing out muscle growth, but this is a far cry from causing actual muscle loss.
2. After a long run, swim or any aerobic exercise, our bodies can be stressed. We feel tired, and some people believe that this exhaustion means we’ve taken something out of our bodies. Really, it’s nothing more than sugars and water. When our bodies are stressed, we produce a hormone called cortisol. Cortisol is released into our bloodstream, and helps make sure we have enough sugar in our blood to ensure we can perform activities that we’re asking our bodies to do. In extreme situations, cortisol calls on the proteins in our muscles to become sugar. But unless you plan on running an ultra-marathon in Dubai, or competing on Survivor, this isn’t something you should concern yourself with.
3. The last contributing factor to this myth is that, for the ill-prepared, it’s true. If you’re asking bodies to perform at a high level, and you aren’t eating or drinking, your body will cannibalize your muscles. This process is called muscle catabolism. Trick to avoiding it: eat food, drink water, keep your glucose levels up. This isn’t rocket science, it’s shop class. Your body is an engine, it needs oil and fuel. If it isn’t fueled properly it starts to wear down.
So, what’s the moral of the story?
The first one is that aerobic exercise does not cause muscle loss, and should not be avoided for fear of wasting away. The second lesson is that if you want to be healthy, you need to do more than just work out – proper nutrition is critical, both for general health but also to ensure that your exercises have the desired effect on your body and fitness levels.
