Have you ever observed a middle aged person stand up after playing on the floor with their grandchild?  Did you notice the way they use their hand to push themselves up, and wonder why?  The reason is as we age we start to lose muscle mass. As a result of reduced muscle mass we lose strength for basic functions like getting up off the floor.  Our metabolism changes as we age if we do not take charge of it.

This process starts around 25 years of age. After we celebrate our 25th birthday we start to lose 2-4% of our lean muscle mass every decade. By the time we are 55 that can have a significant impact.

Resting Metabolic Rate

When discussing metabolism it’s helpful to know what the Resting Metabolic Rate is (RMR). Your RMR is the number of kcal from food that it takes just for you to stay alive, assuming you are at rest and doing absolutely nothing.  A person who has a RMR of 1500 kcal at age 25 may have a RMR of about 1200 kcal by the time they are 55 years of age.  The most common explanation for this decrease in muscle mass is “aging”, but in reality it is more of a life-style issue.

As people start families and careers we become very busy, too often we become more sedentary.   This starts a vicious cycle of inactivity and overeating for the amount of activity we are doing. There are consequences to this cycle.

Muscle versus Fat – Metabolically Speaking

Muscle tissue is very metabolically active while fat tissue is not.  The more lean muscle mass we have the higher our metabolic rate is. Furthermore we require more kcal from food just to stay alive.  It can be hard work to hang on to the muscle mass that we have or rebuild the muscle that we have lost over time, but it is a goal worth having.

Certain kinds of exercise to rebuild muscle mass better than others.  Taking a nice long moderately paced walk in the evenings has health benefits but it is not the best choice to build lean muscle mass.  Muscle is built and preserved through high intensity activity, done at near your maximum heart rate and using many muscle groups.  Examples of high intensity exercise include: jumping rope, running or walking hills, or circuit training.  Not only does high intensity exercise raise your metabolic rate during the exercise, but it raises it for hours or even days after the exercise.  That is where the magic happens!

Taking Charge of your Metabolism

Let me stress another important factor.  Exercise is 100% necessary if we want to fight the traditionally referred to effects of “aging” on our body composition. Good nutrition is also 100% necessary if we want to perform at a high level and look our best.  Every function carried out in our bodies can be either helped or hindered based on the quality of the nutrients that it receives.  Sure, there are changes that occur in our bodies as we age, but it is good to know that with some consistent effort, we can help to slow those changes down and continue to do the things we want to do.