You may hear about metabolic age and what it means for your health. But what is metabolic age, how is it determined, and what does it really mean?
Your metabolic age is how your basal metabolic rate (BMR), or how many calories your body burns at rest, compares to the average BMR for people of your chronological age in the general population.
Continue reading as we explore the theory behind metabolic age, what it means for your health, and how you can change it.
Dr. Natasha Trentacosta is a sports medicine specialist and orthopedic surgeon at Cedars-Sinai Kerlan-Jobe Institute in Los Angeles. She told Healthline that “metabolic age” is a term the fitness industry has been using in recent years.
BMR is just one measurement of a person’s overall health and fitness. “You can’t use BMR as a single measure of your state of health or fitness level, but it can give insight into your state of health,” said Trentacosta.
As with body mass index (BMI), BMR has its critics. According to Trentacosta, neither measure factors in body composition properly. For example, a bodybuilder with a lot of lean muscle could end up with a similar estimated BMR or BMI as someone without the same composition.
Currently, there aren’t many peer-reviewed studies of metabolic age.
“It’s not a data point in research. Metabolic age isn’t something we talk about in the medical community. It does give insight into how you compare to others your age. The marker of the ultimate definition of health it is not,” said Trentacosta.
Your chronological age, simply put, is how many calendar years you’ve been alive. Chronological age is one way to gauge your fitness level compared to your peers.
Your metabolic age is your BMR compared to others in your age group.
“So, if your metabolic age comes out to your chronological age, you’re similar to the rest of the population of people your age,” said Trentacosta.
If your metabolic age is lower than your chronological age, that’s probably a good sign. If it’s higher, you may want to take a look at your dietary habits and exercise routine.
Your BMR is the minimum number of calories it takes for your body to function at rest. So, it includes the calories you burn without so much as lifting a finger. Even when you’re being a total couch potato, you’re burning calories through things like breathing, digestion, and blood circulation.
BMR doesn’t factor in physical activity. This is important because about 60 to 75 percent of the calories you burn each day happen while you’re seemingly doing nothing.
To estimate your BMR, you have to factor in your sex, height (in centimeters), weight (in kilograms), and age. You can use the Harris-Benedict Equation calculator or use the appropriate formula below:
- Male: 66.5 + (13.75 x kg) + (5.003 x cm) – (6.775 x age)
- Female: 655.1 + (9.563 x kg) + (1.850 x cm) – (4.676 x age)
BMR is sometimes called resting metabolic rate (RMR).
Resting energy expenditure (REE) represents the actual number of calories spent at rest. Arriving at your REE requires fasting and measurement by indirect calorimetry. In this test, you have to lie down under a transparent dome. As you relax, a technician monitors your resting energy expenditure.
Though BMR and REE are calculated differently, the difference is less than 10 percent, so these terms may be used interchangeably.
Metabolic testing may be offered at health clubs and medical clinics.
You can estimate your BMR, but calculating your real metabolic age is complex. In a
- body composition
- waist circumference
- resting blood pressure
The researchers used special software and a 5-day diet analysis. The calculation for relative metabolic age was to subtract chronological age from metabolic age.
To get your relative metabolic age, you need data on other people your age. If you’re interested in determining your metabolic age, talk to your doctor, dietitian, personal trainer, or other fitness expert.
“A higher BMR means you need to burn more calories to sustain yourself throughout the day. A lower BMR means your metabolism is slower. Ultimately, leading a healthy lifestyle, exercising, and eating well is what’s important,” said Trentacosta.
Diet and exercise
The best way to stay healthy is through a combination of exercise and dietary habits. You should try not to take in more calories than you burn on a consistent basis.
Improving your metabolic age
Here are a few things you can do to improve your metabolic age:
If you cut down on calories, even if don’t increase physical activity, you’ll probably start losing weight. But when you lower calorie consumption, your body starts to prepare for the possibility of starvation by slowing your metabolism. Now that you’re burning calories more slowly, the weight you lost will likely find its way back.
If you don’t adjust caloric intake but add in exercise, you can lose weight but it’s a slow road. You might have to walk or run 5 miles per day for a week to lose a single pound of fat.
By cutting calories and increasing exercise, you can avoid the metabolic slowdown that keeps you from losing weight. Regular exercise doesn’t just help you burn calories in the moment — it also improves your BMR, so you burn more calories while you’re not exercising.
Tips for increasing your physical activity
- Start the day with a series of stretches.
- Cut down on the time you spend sitting.
- Choose stairs over escalators and elevators, and parking spaces further from the door.
- Take a walk around the block after dinner every night.
- Take a brisk 2-mile walk or bike ride several times a week.
- Join an exercise class or dance class you enjoy (so you’re more likely to stick with it).
- Work with a personal trainer.
If you’re up to it, try some high-intensity interval training (HIIT). This type of exercise involves quick but intense bursts of activity.
Research shows that HIIT may help improve your metabolic rate even after your workout, but with less training time. If you haven’t exercised in a while or you have a health condition, you might want to check with your doctor first.
Better sleep for better metabolic age
While diet and exercise are key factors, getting a good night’s sleep also matters. Research shows that sleep plays an important role in energy metabolism and that insufficient sleep can lead to weight gain. If you have trouble sleeping, try some stretching before bed.
Metabolic age is more of a fitness term than a medical one. It’s a way to compare your basal metabolic rate (BMR) to other people your age. It can offer a general idea of your metabolism so you can take steps to manage weight and improve health.
The best way to lose fat and gain lean muscle mass is to cut calories while increasing physical activity. If you have concerns about your BMR or weight, start by talking with your healthcare provider.