Marathon Training and Muscle Loss (Part 1)

Have you ever wanted to run a marathon or half marathon, but worried about muscle loss or wondered how preparing for such a race might affect your current weight training efforts? Recently, I was approached by a co-worker in his late 30s who is thinking about competing in his first half marathon. "How can I coordinate all that cardio work with my weight training?" he asked. "I've been lifting for years and am concerned that the training process might destroy the muscle mass I have worked so hard for".

This is a good question - and one I didn't have a quick answer for. After giving things some thought and doing some reading, however, I learned the following.

The Quagmire

To start with, we are facing two very distinct goals that target different energy systems. It is very difficult - if not impossible - to weight train with the goal of building muscle mass while at the same time training to run a marathon. To be able to perform your best at one, the other will be forced to suffer.

The Marathon and Sacrifice

If your goal is to run a half or a full marathon, then your focus should be upon training for this event – and weight training should receive less attention. But don't give up lifting weights altogether as you prepare for a marathon! Realize, however, that you won't see any gains in muscle mass. In fact, you'll probably lose some degree of muscle mass.

The goal here is to maintain your previous gains as best you can. Besides, have you ever seen a big, muscular marathon runner? Most joggers and long distance runners are not necessarily "slender", however. They just don't have much muscle mass. One study of a jogging club even revealed that members had an average of 22% body fat.

Why Does This Happen?

Before considering why muscle-building and marathon running are at odds, we must understand two terms: catabolic and anabolic. Catabolic is characterized by destructive metabolism. Anabolic is characterized by constructive metabolism.

In a word, "catabolic" explains why long-distance running and muscle-building are counter-productive to one other. Prolonged running raises the body's cortisol levels. Cortisol is a catabolic hormone that inhibits protein synthesis and is associated with a loss of muscle mass and strength. Cortisol also contributes to fat accumulation.

Cortisol isn't the only problem, however. Testosterone, the primary hormone that helps to synthesize new muscle tissue, has been shown in studies to decrease during long-distance running. As you can imagine, putting your body into this type of catabolic state is detrimental to maintaining or building muscle mass.

So what are your options if you want to continue weight training while preparing for a marathon or half marathon? We'll find out next week in Part 2.

Resources:

Hormonal Response To Marathon Running