If you should you do cardio before or after weights is a question I have seen fairly often. The answer depends on what activity is more important to you and how that makes you set a little enzyme called AMP kinase.
What Do You Want?
If your main goal is getting better at endurance activities like cycling, running etc., then that should come first. If you set your eyes on building muscle mass through lifting weights, then cardio should come afterwards. Ideally you try to do your resistance and endurance training on separate days:
So what is that little enzyme? Er, what are enzymes actually? Time for a really, really short adventure into the world of biochemistry.
Let’s start with what enzymes are: they are molecules that cause chemical reactions in the cells of the human body. Everyone of us has around 75,000 of them and each fulfills a specific task. You may, for example, have heard of “digestive enzymes”, whose role is to break the food you eat down into its components, so your body can build something new out of them.
AMP kinase then is an enzyme that has the role of a “master switch” that helps regulate what kind of proteins muscles produce after exercise. Once this switch is set to “endurance”, your muscles will go and adapt to better endurance. On the other hand, if it is set to “strength”, the muscles are more willing to build the kind of proteins that make them bigger and stronger.
As said in the video, once AMP kinase thinks it figured out what you want during a session, that is where your best results for the day will be.
What About Fatigue?
Good question! If you totally exhausted yourself with either cardio or weightlifting, then naturally whatever comes last will suffer. However, even a moderate half hour session of one or the other gets the AMP kinase into action.
Picture courtesy of “puuikibeach“.