What is DEXA?
The DEXA scan is the gold standard of body composition measurements. It allows you to see exactly how much fat and how much muscle you have. It will tell you where that muscle and fact is, point to associated risks or hormonal issues, or identify muscular imbalances.
For a more detailed look at what DEXA is, and how it can assist you with your health and fitness programme, take a look at this video, produced by Hologic, the manufacturer of the DEXA machines we use.
How does it work?
The scanner passes a small amount of two different X-ray beams through the body. The rays are absorbed or pass through the body in known quantities. Different amount of the first beam will be absobed by fat and by muscle, and the second beam will be absorbed by the skeleton. By measuring the amount of each beam which makes it through to the sensor on the other side, we are able to tell how much fat and muscle and bone there is in that part of the body.
X-rays? Is it Safe?
The amount of radiation you are exposed to in a DEXA is tiny. It is roughly equivalent to about a day’s worth of background radiation from just living, or about the safe as the additional radiation you get from taking a flight from London to Paris. Our DEXA machines are regularly checked and calibrated to ensure that this remains the case. There is absolutely nothing to fear from taking a DEXA scan. We also limit the number of scans a person can take in a year to 6, with individual scans being taken no less than 6 weeks apart.
What’s the procedure?
You will be asked to undress to underwear and remove all jewellery/watches. A hospital gown can be provided if needed. Bras with underwires will also need to be removed. The Dexa technician will position you lying face-up on the bed, ensuring that you are evenly spaced. They will also lightly secure your feet to each other so your legs can’t swing. When the scan is operating the receiver arm will pass over your body in three sweeps, and will gradually build up a picture of you. It is important that you are very still while the scan is happening to ensure the best quality image. Once the scan is over the technician will tell you it’s ok to get up, and dress once again. You’ll be on the table for approximately 4 minutes.
What do you get?
After the scan, the technician will print off a multi-page report, and will walk you through some of the key points. Your trainer can advise you on how best to take advantage of the information given to work into your training and nutrition plan.
How much does a DEXA body scan cost?
When you come to the My Vital Metrics body composition lab, you don’t just get the scan. You also benefit from our teams years of experience and have an expert technician walking you through the key points of your report. A one-off scan starts at £135 and you can benefit from reduced prices when purchasing multiple scans. Book your DEXA scan now here.
What about alternatives?
DEXA is the Gold Standard in body composition analysis. No other method comes close for its consistency, ease of application and specificity. DEXA is also the only measurement which will give you accurate fat mass, fat-free mass and bone mass, not just overall, but in each part of the body. This means that it can double as a measure of how recovery from injury is going, or detect imbalances between the left and right side. It is also the only measurement which can give an indication of visceral fat – this is the fat which sits around the organs. This type of fat is appearing regularly in recent research as being an indicator for a range of health conditions.
Below is an analysis of some of the other methods out there.
This is the most commonly used measure in the medical profession. It’s a simple height and weight calculation. In anybody who has never seen the inside of a gym this might be ok. But once you’ve ever lifted up something heavy, it will cease to be relevant.
BIA / Bioimpedance
This method, most commonly found on gym floors or even in people’s bathroom scales, passes a small current through your body. It is predicated on the idea that muscle and fat will concur that electrical current at different rates. Among the problems found is levels of hydration and numerous other factors also influence this. The machines have consistently failed to produce reliable or meaningful composition results. They are not used in any research on body composition.
Other Frequently Asked Questions about DEXA
Got more questions about DEXA? Maybe some of the below will help you to understand more deeply the report, and the procedure. If you’ve any questions however, please do feel free to email us, or use the whatsapp button in the bottom right hand corner of the screen to get in touch.
Are DEXA Scans safe?
DEXA Scans are considered very safe. The radiation is so low that we (the operator) do not leave the room while it is going on. The radiation is about the equivalent to a 1 hour flight.
Do DEXA Scans use Radiation?
Yes. DEXA Scans use X-Ray radiation to create the image. The radiation dose is very low, but we still will ask you whether you have had any X-Rays within the past 2 months, and if you have we cannot proceed with the test until 2 months have passed since your last X-Ray (Dental X-Rays don’t count)
How long does it take to get DEXA Scan results?
Results are instantaneous, and we will discuss them with you in depth at the same appointment.
Are DEXA Scan results ever wrong?
DEXAs are like any test in that there are things which will make parts of the information less relevant. For example, if you have radio-opaque implants of any kind, these show up as bone, and so we might not be able to rely on the bone figures. In normal circumstances however, DEXA has been shown to be the most accurate and the most consistent and reliable of all methods of measuring body composition.
Can I have a DEXA Scan with a Pacemaker?
Yes, you can still have a DEXA Scan, but we will see the pacemaker on the scan, and it might mean we are unable to use some of the results (e.g. for bone mass) or else deduct the known weight of the pacemaker.
What is BMD in a DEXA Scan?
BMD is Bone Mineral density. It is a measure of how dense your bones are. It is measured in g/cm2. The three measures of bone health are Area – this tells us how big your bones are overall; BMC which is bone mineral content – this tells us how heavy your bones are; and BMD which is calculated from the first two and is able to predict how strong your bones are overall.
What is a DEXA T-Score?
The T-Score in general is a statistical measure to tell you how far you are from the ‘normal’ person. In a DEXA, it is most commonly referring to the T-Score of your bone density. This compares your bone density to the bone of a healthy 30 year old person. If you have a T-score of 0 this means that your bones are exactly the same density as that 30 year old. If you have a T-score of -1, it means your bone density is 1 standard deviation less than this healthy adult. If your T-Score is between -1 and -2.5 this is defined as Osteopenia. If it is -2.5 or less, this is defined as Osteoporosis.
My Vital Metrics will not comment too much on your bone densities, as we are not medical professionals, and the scan we do for whole body composition, isn’t the ideal scan to identify any condition. However, if our scan shows a very low T-score, we might advise you to see your GP about it.
What are DEXA Scans used for?
In their diagnostic context, DEXA scans are used to measure bone density, and to diagnose conditions such as osteopenia and osteoporosis. More widely, they are also good for measuring the amount of bone, fat, and lean mass a person has.
Can a DEXA Scan detect Cancer?
No, the likelihood of a DEXA scan picking up any cancers is minimal as the resolution of scans we use, being whole body would not identify cancers.
Can a DEXA Scan detect arthritis
No, the resolution of scans we use – being whole body – cannot detect artritis.
Can a DEXA Scan show fractures
Most fractures are very subtle, and require a high resolution scan of the fractured area in order to identify them. We use whole body DEXA scans and these cannot identify any fractures.
Can I drink milk before a DEXA Scan
You can eat and drink anything you like before a DEXA scan. Most foods will be added to the ‘lean mass’ figures. In an ideal situation you should minimise what you eat and drink before a scan to get the best results possible. Alternatively as long as we keep the consumption similar between scans, we should get consistent results.
How often should you have a DEXA Scan
We need to keep a minimum of 2 months between DEXA Scans. Outside of this, the frequency of your visits will be up to you. We would suggest that you come in when you think you have seen a change in your body composition, or you are about to change up your training or your diet – e.g. when moving from a cutting phase to a bulking phase or vice versa.
How do I read a DEXA Scan Report
We will walk you though the DEXA report, and explain all the important parts for your particular circumstances. We will then email you with a summary of our findings, as well as the report – so you don’t have to guess at what the figures all mean.