The DEXA scan is widely regarded as being one of the most proven and reliable technologies for measuring body composition. A standard DEXA scan with a Fitnescity partner involves lying still for 10-15 minutes while the machine’s arm moves back and forth over your body to develop a full-body image. A DEXA can be used to obtain an initial body composition assessment and to understand how your body is changing over time.
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Most people are used to stepping on a scale now and then. But monitoring weight – while helpful – is not a precise way of assessing wellness or fitness. Body composition measurement with DEXA can look beyond weight and the traditional body mass index (BMI) to determine body fat distribution.
How does a DEXA scan work?
DEXA, or Dual Energy X-Ray Absorptiometry, is one of the most proven and reliable technologies for measuring body composition and is capable of collecting segmental fat, lean, and bone measurements in just 15 minutes.*
The Technology
The DEXA scan is a large table with a C-Arm that moves back and forth scanning the body from head to toe. It emits photons that attenuate at two different energy levels, allowing the machine to distinguish between soft tissues and bone mass. Because of the difference in density between bone, fat, and lean mass, the unique combination of frequencies form the full-body image and analysis.
DEXA scans have a high degree of accuracy, but even more notable is their precision. The true value of a DEXA is the ability to track small (and large) changes in body composition and distribution over time. DEXA scans are highly comparable, but it is important to always test on the same machine for best results.
Please note that DEXA scans do subject you to small amounts of radiation. A whole body scan produces a level of radiation equivalent to flying by airplane from Chikago to California.
Your Appointment
What happens during your appointment? You will arrive to the test center 15 minutes prior to your appointment having followed the proper pre-test protocols. Upon arrival, the center will provide any necessary paperwork and bring you back to their testing space. After removing all metal (jewelry, zippers, etc.), you will lie down on the table and a technician will help position your body to get the best image. The C-Arm will move up and down your body for about 10-15 minutes until it’s captured a complete image.** Some locations may provide a gown to be worn for the duration of scanning.
What are the benefits of a DEXA scan?
Whether your goal is to lose, gain, or maintain your weight, the DEXA scan provides an in-depth body fat analysis including segmental fat mass, lean mass, and bone density.* Knowing this information about your body is crucial for optimizing your wellness, preventing disease, and tracking change over time. Most people are accustomed to stepping on a bathroom scale every now and then, but monitoring weight – while helpful – is not a precise method of assessing wellness and fitness.
Look beyond the bathroom scale.
Have you ever been surprised or frustrated by your weight after starting a new training plan or diet? This is not unusual, as most people do not fully understand the daily fluctuations that happen in the body throughout the day, or what weight means. The DEXA scan is a great monitoring tool because it allows you to see where your fat and muscle are located, and how they are changing. Sometimes, when in a caloric deficit or when macronutrient intake is unbalanced, the body can actually draw energy from muscle mass rather than fat mass during exercise. Regular testing can help ensure you are gaining or losing mass the way you want to and are on track to reach your goals.
Additionally, one of the big causes of unexpectedly increased body fat is Visceral Adipose Tissue: unseen fat that lives between your organs. This is the most dangerous type of fat, but because it lies deep within the body, it can’t be seen with the naked eye. A lean person can have unhealthy amounts of visceral adipose tissue, but only a DEXA scan can accurately provide this information.
BMI vs. DEXA
BMI is one of the most popular methods of determining how healthy one’s weight is for their height. However, this method has numerous failings. The body is comprised of different substances which decrease in density from bone (the most dense) to fat (the least dense) with muscle in-between, the combination of which can result in similar weights despite drastically different body compositions. For example, a lean individual with high muscle mass can weigh the same as a severely overweight individual with low muscle mass.
Because BMI is based solely on height and weight, it does not take into account what other factors contribute to weight. This is one of the reasons why body composition scans are so valuable. A DEXA scan is able to accurately isolate fat and lean mass in each part of the body to provide the most accurate image of your wellness and evaluate wellness risks.*
Note: BMI is a valuable measurement for evaluating the stress on joints as a result of weight. Every pound of body weight places four to six pounds of pressure on each knee joint, regardless of contributing factors.
How do I prepare for a DEXA scan?
Follow the proper DEXA scan guidelines to ensure accuracy:
Do not wear any items with metal or hard plastic, such as buttons or zippers. Inform the technician if you have metal in your body. Some locations may provide a gown to be worn for the duration of scanning.
Do not take calcium supplements for 24 hours prior to testing.
Best practice is to perform a four-hour fast prior to testing.
Arrive hydrated to your test.
Refrain from this test if you believe you may be pregnant.
Attire: Wear comfortable clothes, such as gym attire.
How often should I test?
DEXA scans have a high degree of accuracy, but even more notable is their precision. Their true value is the ability to track small (and large) changes in body composition and distribution over time. DEXA scans are highly comparable, but it is important to always test on the same machine for best results.
How often you should test depends on the intensity of your training/nutrition plan. We typically recommend testing every 3, 6, or 9 months:
If you are just trying to maintain your current body composition, testing every 6 or 9 months to ensure you’re on track is sufficient.
If you are starting a new fitness plan, training for a race, cutting for a show, or trying to improve your wellness in any way, we recommend testing more frequently to ensure you are on track for your goals and not experiencing any unexpected side effects. Depending on the intensity of your training and your goal timeline, we recommend testing every 3-6 months.
Combining Tests for Best Results
A common problem people experience when trying to change their body composition, is not fully understanding how diet and exercise affect muscle growth and metabolism. Cutting calories too much or overexercising can sometimes have the opposite effect you’d expect: Metabolism can slow or your body can break down muscle for fuel instead of building.
Getting frequent DEXA scans is a great way to ensure your mass is changing where and how you want, but won’t give you a comprehensive picture of what’s happening inside your body. A Resting Metabolic Rate Test (RMR) is the perfect companion for a DEXA. This test measures how many calories your body burns per day at rest and is critical for designing a personalized and effective nutrition plan.
What results are included with a DEXA scan?
Regional Body Fat
Body composition scans with DEXA provide precise and accurate data on total body fat percentage, total fat mass and fat-free mass. Most importantly, what is unique about this body composition technology is that it provides regional body fat results (trunk, arms, legs, pelvis and android/gynoid regions).*
Precise, accurate and segmental (regional) body fat data can have many benefits such as:
Supporting decisions on training regimens and nutrition plans.
Understanding and monitoring risks related to muscle imbalance, body fat distribution and bone density.
Bone Density
DEXA results often include a total bone mineral density (BMD) and z-score measurement as well. A Fitnescity scan does not provide a segmental bone density analysis or spinal measurements. Fitnescity scans are for personal wellness only, and not for use in diagnosing illness or disease, such as osteoporosis or cancer.
What is body composition?
Body fat, otherwise referred to as Adipose Tissue, is a connective tissue found throughout the body that regulates metabolism by communicating with both organs and the central nervous system through the release of hormones. The presence of sufficient body fat is an important part of a healthy body and plays several important functions, but becomes dangerous when it builds up in excess.
Adipose Tissue
Adipose tissue increases as a result of fat cells growing in both size and number. Consuming too many calories over a long period of time causes the size of fat cells to grow and be stored across the body. Dieting or other weight loss strategies can shrink the size of these cells, but once created they cannot be destroyed. Larger fat cells are more resistant to insulin, leading to increased risk of Type II diabetes and cardiovascular disease. This is part of the reason why increased levels of fat in the body are associated with heart disease, stroke, Type II diabetes, cancer, and early mortality.
There are three main types of adipose tissue that perform different and very important functions in overall body function:
White Fat
White fat is what one typically thinks of when talking about “body fat.” It is designed for fat storage and found mostly commonly around the belly, hips, and thighs. This is the fat that you can grab in your hand (subcutaneous) and accumulates around your organs (visceral). White fat cells secrete over 50 types of hormones, enzymes, and growth factors which drive food intake, insulin sensitivity, and insulin secretion. An excessive amount of white fat disrupts hormone function, causing a number of wellness concerns such as heart disease, stroke, Type II diabetes, cancer, and early mortality.
Brown Fat
Brown fat’s primary function is to produce heat in cold temperatures, protecting the body from hypothermia. This happens by breaking down sugar and fat to create energy, so brown fat is also involved in regulating the metabolism of these substrates.
Brown fat is highest in infancy and decreases with age.
Beige Fat
Beige fat cells are a kind of combination of white and brown fat cell characteristics. They are typically found within white cell clusters near the collarbone and spine. These cells are like a combination of white and brown fat cells because although they are believed to be derived from white cells (through a process called “browning” which is due to exposure to cold temperatures, good nutrition, and exercise), they burn energy like brown fat cells.
Just as not all fat is created equal, the location of all fat is not equal either. Brown fat is found in the upper back and under the clavicles while white fat typically collects around the belly, hips, and thighs. However, the most dangerous place for white fat is deep below the skin’s surface, where it can’t be seen with the naked eye. Let’s talk about the types of places fat can be found:
Subcutaneous
Subcutaneous Fat is the layer of fat you can hold in your hands, located just below the skin’s surface and typically accumulating around the waist, hips, back, butt, and thighs. Subcutaneous fat cushions bones and joints, but too much can increase the risk for adipose-related diseases.
Visceral Adipose Tissue
Visceral Adipose Tissue (VAT) is white fat which accumulates deep in the abdominal cavity and wraps around the digestive organs, pancreas, intestines, liver, and heart. High amounts of VAT are associated with increased risk of cardiovascular disease, diabetes, and cancer. Visceral Adipose Tissue is often one of the reasons why an athletic person will measure at a higher body fat percentage than they expect – This fat is not visible to the eye and doesn’t decrease as a result of fitness alone.
It is well-established that both the distribution and volume of fat, especially visceral adipose tissue (VAT), is a predictor of long-term wellness. While normal amounts of visceral fat pad and protect organs, an excess amount of VAT is strongly associated with metabolic syndrome and increases risks for cancer, stroke, diabetes, cardiovascular disease, and hypertension. Excess VAT can impact lifestyle by increasing the risk of dementia, depression, arthritis, sexual dysfunction, and sleep disorders. Storing excess fat around the organs increases the production of inflammatory substances that interfere with hormones that control appetite, weight, mood, and brain function.
A unique bonus to receiving a DEXA scan is the bone density measurement. DEXA machines are, in fact, most commonly used in clinical settings for diagnosing bone-related health risks such as osteopenia and osteoporosis.
Bone Density
Bone density refers to the amount of minerals (mostly phosphorus and calcium) in your bones. The more mineral content, the “denser” (and stronger) your bones. Bone density testing measures the strength of your bones. It can also reveal whether you have a bone disease and predict how likely your bones are to break.
For instance, osteopenia is a loss of bone mass that causes your bones to become weaker which stems from the loss of calcium. When you start losing calcium, your bones can become more brittle. Your body is unable to replace the calcium as fast as it loses it and eventually, this can lead to another serious bone condition called osteoporosis.
Osteoporosis also weakens the bone, but it’s more serious than osteopenia. Your bones become so thin that even a slight bump against the wall can lead to a fracture or break. Your bones may even start to form holes, or pores, because so much material has been lost.
Anyone can develop osteopenia or osteoporosis. But these bone diseases tend to affect individuals over the age of 50 more than younger people. And women are usually impacted more than men.
What is a “normal” body fat percentage?
The pounds of fat and lean mass everyone’s body contains depends on a number of variables including height and age. So, in order to evaluate if your fat mass is healthy, we use the body fat percentage measurement to make everyone’s unique data comparable.
National Comparison Data
DEXA is the only body composition analysis tool that uses a large-scale database of population scans to compare your results with people who are similar to you. After receiving your Fitnescity Dashboard, you will be able to see how your body fat percentage compares to national averages for those of the same age, gender, and race as you.
Comparisons are based on the National Health and Nutrition Examination Survey (NHANES), which collected large-scale data on whole body DXA scans of participants age 8 years and older to provide nationally representative data on body composition. The study also collected data to examine the association between body composition and other health conditions and risk factors, such as cardiovascular disease, diabetes, hypertension, and activity and dietary patterns.
FAQs
Why should I test with Fitnescity?
By booking with Fitnescity, you receive easy-to-understand digital insights, a personalized dashboard that allows you to view your progress over time, and a physician follow-up call so you can go over your results in depth.
Do I need to get a physician referral?
No. If your location requires a referral, we will get it for you.
How much does a DEXA scan cost?
Fitnescity DEXA scans range from $100 to $330. Visit our location finder to find a scan near you.
Find more answers or chat with a team member in our Help Center
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*Individual location results may vary
**Individual location process may vary
Fitnescity does not provide medical advice, diagnosis, or treatment. Always seek the advice of your doctor or a qualified medical professional if you have any questions about your results.