What? Metabolism Doesn’t Slow with Age?

WARNING!  This blog is a LITTLE snarky at times! 

Many of us have noticed that our bodies seem to go slower as we get older. And it seems more difficult to keep extra weight off.  But now there is some shocking new research.  

Perhaps you have seen the headlines.  Something like, “New research says metabolism doesn’t slow with aging.”   What???  What gives?  I would wager that there are not just a few, but millions, of people who have experienced the opposite. 

So I looked into it.

What Does the Research Actually Say? 

The research does indicate that our metabolic rate, or how quickly we burn fat to make energy, does stay the same from ages 20-60.  No slow down at 30, 40, etc. or even at menopause as previously thought. 

Perhaps leading to even more head scratching is the finding that there is no difference in metabolic rate between men and women.  Now hold on.  I for one have heard tales from very many women who are frustrated when they and their husbands/boyfriends go on the same diet.  The weight just seems to fall of the man, while the woman lags behind, struggling and frustrated. 

The Caveats

Unfortunately, in order to make a great headline (aka, “click bait”) results of the research were unqualified.  In other words, nowhere was there an explanation that loss of muscle mass as we age is a huge reason why it seems that our metabolism slows down.  Muscles are a major driver of our metabolic processes because, after all, movement takes energy.  And yet, research statistics have shown again and again that our muscles tend to lose mass at a rate of about 3-5% per decade. 

What they are really saying is that the rate we burn calories, once you take the size of our muscles out of the equation, actually stays the same over time.  At least until we are about 60. Then it does start to slow down to the tune of 1% per year. 

It is also about lifestyle.  Here the research at least explains that most people, as they get older, tend to be less active.  For many reasons.  Like it starts to hurt.  Like they have a job that requires a lot of sitting.  Like having lunch with friends seems like a better idea than pick-up basketball.

They do mention that adding in some strength training is one of the ways to keep our metabolisms in good shape.  As is getting enough sleep.  As is doing the “right kind” of exercise. 

What Can Help?

Here is where some of the supporting research gets pretty entertaining, if not totally useless for most of us.  Dr. Ed Coyle, who runs a Human Performance Laboratory in Austin, Texas, has discovered that a person can overcome inadequate metabolism brought on by a sedentary lifestyle by simply taking 8,500 steps a day, spaced throughout the day. 

His findings suggest that if we are sedentary the rest of the day, there is a thing called “exercise resistance” that happens.  Meaning, you cannot sit all day and then make up for the bad effects by going to the gym for an hour.  This is why he suggests doing those 8,500 steps throughout the day.  In fact, lots of other research has supported the idea of throwing in more activity throughout the day. 

What if you don’t have the time or opportunity for those 8,500 steps?  Instead, Coyle says you can jump up from your seat five times every hour, and do 4 second bursts of all-out exercise! I don’t know about you, but I find the visual on this somewhere between hilarious and at least smile-worthy.  Seriously?  Do you know even one person who is likely to do that? 

Here’s another one.  Another lab discovered that if you drink no less than 500 ml of water (that’s about a U.S. pint), you can increase your metabolism by around 24% for the next hour.  Great.  This does speak to other stats that show that many of us do not drink enough water during the day.  Not to mention that as we get older we tend to drink less (water) because our sense of thirst diminishes.  So there is that. 

There is even more potential for confusion. (Editorial comment:  Isn’t there always?)  There is research that says anything over 4,000 steps a day, or around 30 minutes of walking is enough to get us started on getting some health benefits from it.  Most organizations concerned with health concur.  Hence the recommendation that we all get in at least 30 minutes a day of moderate exercise to keep us in the pink, sort of. 

How Do We Make Sense of It? 

To start to sort this out, I am going to dive into a bit of physiology.  Feel free to skip this part if you want, even though you have obviously hung in and gotten this far. 

Anyway, the research about the 8,500 steps and the research about our metabolism not slowing is based on the use of fat.  More specifically, the triglycerides that float around in our blood.  They measured the use of fat to maintain our metabolisms, which relates to how we burn calories and what happens if we eat more calories than we burn.  Triglycerides are formed when the food we eat gets broken down, so that it can be used for energy.  If we eat more than we need, triglycerides float around in our blood (and get deposited as fat stores), and can cause heart disease and some other health problems. 

But there are many other things going on that can mess with our health besides triglycerides, although that is a very big one.  Our overall health can be helped by moving more because that helps our circulation, hormone levels, organ function, use of insulin, daily function, good cholesterol (HDL), and brain function.  These are some of the things that are included when they are recommending 30 minutes of moderate exercise on most days for health benefits. 

There you have it. That is the skinny on what could be the difference in recommendations.  Metabolism is one thing (again, it’s a big one), but it’s not everything. 

Bottom line:  Moving is good, and moving often is better than only getting in gear once a day.  Strength training is an additional way of moving that can help us burn more calories in the long run, as well as keeping us strong. 

So, keep moving! 


© 2021 Kristen Carter. All rights reserved
Photo Credit: invincible_bulldog / iStock

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