The health and fitness world just cannot come to a decision about the relationship between cardio and resistance training. Trainers have had their say, academics have had their say and even doctor are having their say. With so much information out there it can be hard to make sense of it all. So here it is, my summary of what the consensus is.
This all relates to concurrent training. Concurrent training involves successively training with endurance exercises and then resistance ones. So you might start out with a tough cardio session and then jump straight onto weights. Pretty typical, right? Well the idea is not just to reach your goals. It is to do so in the most efficient way possible. And the debate surrounds this idea of what is the most efficient way to build muscle? Effectively, is cardio inhibiting prospective muscle gains?
Muscle gains happen when protein synthesis occurs in the skeletal muscles. So anything that encourages this is what you are looking to achieve and anything that interferes with it is to be avoided. This is where we have to rely on the science to tell us exactly what impacts upon the synthesis we want.
Well the protein that is available to our body depends on what and when we eat. So people have utilised nutrient timing more and more in recent years to try and impact this. For example, most people who train will follow a workout with some high-quality protein, like a whey protein shake. The idea is that this then enhances the protein synthesis that we need. The science, which I will link at the bottom, is very much inconclusive on all of this. But what does come across is that a post-exercise shake can interfere with muscular hypertrophy when you are training concurrently.
But it never is just as simple as that. Plus, if it had been conclusively established that nutrient timing and concurrent training didn’t go hand-in-hand then this debate wouldn’t even exist. The fact is there are loads of different factors that account for that interference with hypertrophy. The type of cardio, for example, can have an effect. High-impact cardio like jogging is thought to have a more negative impact, whereas something like cycling can actually help build size and strength. The volume of exercise is a factor too. If you prioritise cardio as if you were training for a marathon then this will take away from some of the muscular gains. But if you reduce the volume of cardio then it can help facilitate the work you do on the weights.
The science is still out is something you hear an awful lot with these kind of debates and I’m afraid that is the case here. But like with the examples I gave above, there are certain things that we can be fairly certain about. Low-impact cardio in a relatively low volume can actually help improve hypertrophy. As the impact becomes greater and the volume increases, this effect starts to flip. Separating cardio from resistance training eliminates the risk of getting the balance incorrect and is kind of like being safe rather than sorry. At the same time, you then eliminate any potential benefits that nutrient timing can have on any concurrent training.
Here are some of the scientific studies that focus on this whole topic: