DEXA Scans: My Results & Three Elements Essential to Longevity

The utility of DEXA Scans, understanding results, and outcome-based goal setting for three elements central to longevity.

In the middle of a DEXA scan on January 8, 2022. Toronto, ON.

Over the past weekend, I had a DEXA scan (dual-energy X-ray absorptiometry) done in order to measure three key indicators that are crucially important to longevity. This article will explain the purpose and utility of DEXA scans, leveraging my results as a case study, and then briefly explain the importance of these three areas along with actionable strategies to begin making improvements in each. 

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What’s a DEXA Scan? 

This tool is used to measure bone density and body composition which is the percentage of lean body mass and fat. DEXA scans are considered one of the most accurate and comprehensive body composition tests. This technology has become widely available through clinics in and around most developed cities.

Obtaining a DEXA scan at certain intervals (i.e., quarterly, semi-annually, annually) allows you to accurately track your progress in these key areas over time. Make sure to price them out, in consideration of your budget, in advance as going for multiple scans a year can add up.

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My Results

The screenshots below outline the results of my DEXA scan and describe key measures, their calculations, and the importance of each. As the report provides succinct descriptions, I’ll just highlight the key results and add a few notes where applicable. 

• Total Mass (lb): 198-200

  • I was weighed twice: 198lbs on the scale and 200lbs on the DEXA machine.

• Fat Mass (lb): 26.6

• Lean Mass (lb): 165.2

• Body Fat (%): 13.3

• A/G Ratio: 0.71

• BMD / Age Matched Percentile: 1.51 / 100

The average Bone Mineral Density (BMD) for my age group is 1.20 (see left vertical axis). In comparison, I sit just above 1.503 (I’m the black dot in the top left corner of the graph) which is in the 100th percentile.

Most overweight men have a higher percentage of fat in their android region (waist) compared to their gynoid region (hips). As seen in the table above, my A/G ratio of 0.71 is a strong positive result as it means I’m storing more fat in my hips than in my waist.

Having just come off the holidays where I eat a little more and exercise a little less than usual, I believe this number is slightly inflated compared to where I sit most of the year. Keep in mind this is my total body fat percentage. My android, or waist/stomach, body fat is 9.9%.

This measure is also known as the Appendicular Lean Mass Index (ALMI). For reference, pro athletes generally have an ALMI/RSMI ranging from 13 to 14 kg/m^2. I touch on sarcopenia and the importance of muscle strength below.

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Outcome Setting

The utility of any result, measure, or indicator increases with the number of data points obtained. An initial scan sets a baseline to which we can compare future scans, allowing us to measure improvements and track progress over time.

In particular to DEXA scans, there are three key areas crucial to extending lifespan and improving healthspan, which we seek to measure and then improve upon: bone density, body fat percentage, and lean muscle mass. 

Increasing Bone Density

Bone density is critically important to extending lifespan, especially as we age since increased frailty is associated with a higher risk of mortality. For many elderly, a fall is the start of the end. Higher bone density can be the difference between falling down and breaking a hip and standing up, brushing yourself off, and continuing with your day.

There are other facets to fall proofing yourself, an underestimated but critically important part of aging well, but for the purposes of this article our focus is improving bone density. Weight and strength training, a topic I’ll be covering in a future article titled Lever #3: Exercise has proven to be one of the most effective methods of increasing bone density.

In addition, it’s important to have a diet that consists of foods that provide us with the vitamins, minerals, and other compounds we need to build strong and dense bones. Some of these staples include eating more vegetables (particularly yellow and green in colour), calcium (kale, yogurt, milk, beans, sardines), vitamin K rich foods (sauerkraut, cheese, natto), vitamin D through sun exposure, eating more protein, consuming omega-3 rich foods (oily/fatty fish such as mackerel and salmon, flax and chia seeds, walnuts) and ensuring a healthy intake of magnesium and zinc (nuts, legumes, seeds, whole grains).

Lastly, stopping smoking, avoiding excessive drinking, and maintaining a healthy weight are crucial to many parts of your health, including improving bone density and strength. 

Shedding Fat

Being obese or overweight has significant and causal ties to a reduced quality of life and leading causes of death worldwide including heart disease, stroke, diabetes, and some types of cancer. Maintaining a healthy weight year-round for the majority of your life will not only improve the quality of your day-to-day life but will also put you at a lower risk of premature death. Losing weight is a challenging endeavour, but I strongly believe it is one that anyone with the knowledge to implement a few simple daily practices and a strong enough why can accomplish.

If you’re accustomed to eating in the morning, start with nailing your breakfast by implementing the ‘30 in 30’ rule. Tim Ferriss, the author of five NYT and WSJ bestsellers including The 4-Hour Body, argues that doing this can help someone lose a significant amount of weight. This rule states that you should consume 30 grams of protein within 30 minutes of waking up.

A perfect breakfast would consist of something such as eggs and/or egg whites, spinach, black beans, and salsa. This combination of protein and insoluble fibre (from the beans and dark, leafy greens) will increase satiation and help curb cravings later in the day. Of course, you can get creative and make something that suits your palate as long as it follows the ‘30 in 30’ rule and ideally contains some insoluble fibre as well.

It’s also important to focus on drinking lots of water throughout the day. Not only will this make you feel full, but being properly hydrated plays a role in helping the body perform its key functions. Losing fat and maintaining a healthy weight is a vast topic and one we’ll get into more depth in the future. Drinking lots of water and focusing on nailing breakfast is a great place to start and will yield positive results for those looking to shed fat.

If you want to do a deeper dive, I highly recommend picking up a copy of The 4-Hour Body. Skim the Table of Contents and read the sections that are applicable to you. It’s a holy grail for many health-related topics and provides tons of actionable tools and tactics to lose fat and put on muscle. 

Building Muscle

There are two important variables when it comes to building muscle: muscle size and muscle strength. As we age, we’re subject to sarcopenia which is muscle atrophy, or muscle loss, that occurs with aging and immobility. Sarcopenia is characterized by the degenerative loss of skeletal muscle mass, quality, and strength. Since it’s more important to have adequate strength, rather than big muscles, in order to decrease our mortality risk, training to build strength should be our primary focus. As a byproduct, we will of course gain muscle mass in the process of building strength.

Strength training must be approached cautiously as, apparent by observing the attendees of any gym, the number of ways to do it wrong vastly outweigh the ways to do it right. Of the many principles to keep in mind while lifting weights, priority number one should always be to avoid injury. Before deciding to begin lifting weights, take the necessary time to educate yourself on proper form. Start with excessively light weight and film yourself to ensure your form matches the gold standard. This doesn’t have to be a complicated or overwhelming process.

For example, if you’re learning to squat, find one of the countless instructional videos online. Generally, selecting the one with the most views serves as an indicator that it is a reliable source. Watch the video over and jot down a few mental notes you’ll want to keep in mind while performing the movement. Keeping with our squat example, some of the important prompts I run through my head are: break hips and knees at the same time, don’t allow knees to cave in, track knees directly over toes, bar travels a straight vertical line, and so on.

If you’re just starting out on your strength training journey, start with full-body sessions three days per week. As you begin to become more advanced, you may decide to transition to a two-day split (i.e., upper and lower body) and eventually a three-day split (i.e., push, pull, legs). I wouldn’t recommend breaking strength workouts down any further (i.e., a five-day split: chest, back, shoulders, arms, legs) as they become extremely inefficient and we derive little benefit considering our aim of longevity.

Strength training and weightlifting was my first love in the world of longevity and is certainly one of my favourite topics to discuss. Being one of the sub-levers of exercise, it’s a large topic and one that Longevity Minded will cover in extreme depth over multiple future articles. 

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The Three Musketeers of Body Composition

Going forward, we can now think about bone density, body fat, and lean muscle mass as the three key components of body composition. The quality of each of these has profound impacts on how we look, how we feel, and the likelihood that we will live a longer and healthier life.

Work to improve each by using the suggestions above, conducting your own research, and staying tuned to future installments of Longevity Minded. Don’t allow yourself to become overwhelmed. Take the development of new habits in stride and enjoy the process of transforming your body into the version of you that feels, looks, and performs the best. 

And, as always, please give me feedback on Twitter or by hitting reply to this email.

Much love,

Jack