Not Seeing the Results You Want? Check Your RMR.

There are tons of acronyms and terms that get thrown around at the gym, from AMRAP to PR to WOD. But there’s a surprising health metric that not enough people understand: RMR, which stands for resting metabolic rate. RMR is the energy your body uses when you’re doing absolutely nothing—your base energy burn, aka how many calories you need for your body to perform basic functions like breathing, brain function, and cellular activity.

So why is this number so important, and is there anything that can be done to improve your own resting metabolic rate? Let’s find out.

Why does it matter?

Essentially, RMR is the energy your body burns naturally on its own, before any kind of exercise or food gets involved. Your body’s natural RMR is crucial to support breathing, blood circulation, and brain function, according to the National Academy of Sports Medicine.

Surprisingly, your RMR makes up for 60 to 75 percent of your total daily energy expenditure—so it’s actually pretty important in understanding how much energy your body needs to function properly (exercise, on the other hand, ranges from 15 to 30 percent). Understanding your personal RMR (your minimum requirement for calories) can help you optimize your body’s performance, as well as enable you to meet fitness goals and maintain a healthy weight. For example, if you’re super active and want to add muscle mass, your RMR can help inform you how much more food you should be eating.

What can impact your RMR?

A couple things can impact your RMR. Perhaps unsurprisingly, the younger you are, the better your RMR, since people’s metabolism in general tends to slow down by age 40. Your sex also matters, as men tend to have higher resting metabolic rates than do women (mostly in part to greater amounts of lean mass).

Female RMRs are not totally fixed, however; they tend to speed up in the week before menstruation due to hormonal fluctuations (hence, an increase in appetite). Similarly, thyroid disorders, which also cause hormonal fluctuations, can likewise cause a person’s metabolism to speed up or, on the flip side, slow down, which changes their resting metabolic rate. Pregnancy plays a role, too. The increased demand placed on your body to grown another body requires more energy, thus increasing your RMR.

How do you find out your RMR?

RMR is best calculated first thing in the morning, before eating and coffee, when you’re body has truly been at rest (ie: sleeping). One of the most accurate ways to calculate resting metabolic rate is by going into a laboratory setting and breathing into a mask that will calculate it for you. It will take your oxygen consumption along with your, height, weight, age and activity level into account and compute your RMR. There are some gyms and fitness centers (the Health Promotions office at Wallace Creek is one of them) that offer this test for a fee. If you’d rather skip the cost, there are also predictive equations such as the Harris-Benedict equation that will give you a rough estimate—based on your height, weight, age, gender—of how many calories you burn at rest. (You can just Google “resting metabolic calculator” and find an estimate, too.)

Can you change your RMR?

There’s a lot about a person’s resting metabolic rate that’s fixed and unique to them, however, there are a few things people can do to make sure their metabolism is as efficient and effective as possible.

***I do not want anyone obsessing over this number like the number on the scale. This information is simply a rough measurement to base your nutritional intake off of.***

First off, and I touched on this in the beginning of the blog, lean mass burns more calories to maintain then fat tissue. This is why individuals with greater lean muscle mass (and men typically have more lean mass by nature) have higher RMR than their counterparts. Outside of simple strength training, studies are showing that high intensity interval training (HIIT) may have more of a positive impact on RMR than other types of workouts for up to 12 to 24 hours after completion. But keep in mind that there is such a thing as excess—too much exercise of any kind can trigger an inflammatory response in the body, which will slow RMR. Plus, going too hard too often without enough breaks can put you at risk of injury. So take your recovery days seriously if you’re working in more HIIT into your routine.

A simpler-to-achieve (read: lazier) RMR boost can be found in your water bottle. Staying hydrated can increase your metabolism by as much as 30 percent. It also helps with the elimination of waste, prevents overeating, and helps the body metabolize food. Fluids aren’t the only intake that’s of import, either; we burn calories when we eat because it requires energy to digest food. Foods that are a little bit higher in protein and fiber tend to require more energy to digest. 

One action that’s not beneficial to your resting metabolic rate? Dieting. When you restrict calories below your resting metabolic rate it slows your RMR in as little as two weeks. Your body goes into energy-and-fat conserving mode (aka starvation mode). Do this for too long and you’ll lose lean muscle, further lowering your metabolism, because your body will literally eat itself to have enough calories to sustain basic functions. For many of my clients, we have to start their nutrition plans by eating at their RMR requirement. Too many are severely under or over eating. Some even see weight loss simply by making this adjustment. Once you’re body is used to consuming the calories it needs, you can start to adjust your calorie intake slightly, but keep calories above your resting metabolic rate. This allows your body to burn calories like it should and still allows you to lose weight at a slow, gradual pace.