I recently took a VO2Max test, a DEXA Scan, a RMR test and a blood sugar test to give me an overall picture of my health and fitness. I wanted to give myself a benchmark to measure progress against and to help inform my training plan in 2023.
Before I did the tests I would have assumed that my results would show:
- A decent aerobic level, with fairly well developed fat burning metabolism.
- That I’m a bit overfat
- My Zone 2 is higher than expected
- My Vo2Max is lower than my Garmin App thinks it is
- I don’t eat enough protein. I find it quite hard to get enough protein as a vegetarian with a fairly relaxed approach to eating a balanced diet
I did 4 tests to give me an overall view of my health and fitness. These tests were:
- Sub-optimal VO2Max test. to measure anaerobic threshold and calculate my heart rate zones
- An HbA1c blood test. To test my blood glucose levels
- DEXA scan. To measure my body fat and bone density
- Resting Metabolic Rate. To understand calories used at rest
Some of these tests were really useful. They did confirm some of my assumptions. But some of the tests gave me completely new insights or were contrary to my assumptions.
My VO2Max test
The VO2Max test was my main reason for taking these tests. I wanted to get an accurate view of my anaerobic threshold and my heart rate zones. This would in turn give me confidence that my zone 2 training is at the optimum level, i.e. putting the most stress that will increase my aerobic base without going above the threshold.
The test was carried out on a Watt Bike, I wore a max that measure the oxygen in and CO2 out. This test equipment then compares these to your heart rate to provide your aerobic and anaerobic thresholds.
My graph from the test is below:
Threshold and Zone 2
From my graph, you can see that the point where C02 (carbon dioxide) exceeds V02 (oxygen) is about 10:30 into the test. At this point my HR is 135 bpm. This is therefore my anaerobic threshold (also known as lactate threshold).
From this measure, your zone 2 training zone can be established. From this test my heart rate zones were established as:
On the diagram above you can see that the test has set my Zone 2 training zone as 115 to 126 bpm. This was really interesting as this is in line with a number of the simple methods or calculations I’ve found over the years to measure your thresholds and zones. You can read a bit more about this here.
I have confidence in the advice for Zones 1 and 2 but have questions the analysis were my higher zones. I generally go with the science, but a zone 5 of greater than 149 bpm seems very low for me. I regularly go well above this when doing VO2Max intervals. I can generally get my heart rate to 172 bpm or above for up to 4 mins, which I consider 90% of my max heart rate. I can also ride or run for extended periods with a heart rate in excess of 150 bpm. Which wouldn’t be possible if this truly was in zone 5.
Fat Burning
The other key item to understand from the VO2Max test is my fat burning capabilities at different heart rates. The diagram below shows the calories from fat in purple and calories from carbs in yellow. You can see that even at very low levels I am using a high proportion of carbs. This was quite a big surprise, I have done a lot of zone 2 training last year, and therefore assumed that my fat burning would be well adapted.
My hypothesis is that I am more reliant on carbs at lower intensities because I have a carb heavy diet and I snack too much on sweet treats, particularly in the evening. The advise from the test centre was to do my zone 2 sessions fasted to train my body to utilise fat, which makes sense. I also plan to make dietary changes to increase the proportion of fat and protein in my diet while reducing carbs.
VO2Max
Another key thing for me to understand was my VO2Max. Whilst this isn’t an indicator for Zone 2, it does give me an indication of my overall fitness, it also allows me to compare it to the various fitness apps that use algorithms to estimate VO2Max.
As you can see my VO2Max was estimated at 45.2 – this means I can process 42.5 ml of oxygen per kg of bodyweight – and is considered excellent for my age. I was obviously happy with the result. And a little surprised as I did expect it to be lower. Interestingly, my Garmin Connect App estimates my VO2Max to be 46. Which is not too far away from the test result.
Key takeaways from my VO2Max test
I got almost everything I needed from the VO2Max test in terms of understanding my thresholds, my Zone 2, my VO2Max and my fat burning capabilities. My higher level zone analysis feels questionable and I will continue to look into that to try and better define those.
What this means for me is that I’ll focus my zone 2 training between 115 and 126 bpm. I’ll also be doing as many of those as I can fasted to improve my fat burning. I’ll continue to aim to get my heart rate above 172 bpm during VO2Max intervals, despite the zone 5 definition here. I’ll also be adjusting my diet to help with fat metabolism and in line with the HbA1c blood test results below.
My HbA1c blood glucose test
The test itself was a simple finger prick, the blood taken was then put in a fancy looking analysis machine for, I think about 20 minutes. At the end I got a reading of 38 mmol/mol.
This means that I had slightly high blood sugar levels. This is indicated in the diagram below, with the marker in the orange band. I did the test first thing in the morning. I hadn’t eaten since the evening before. I was therefor slightly surprised at the raised levels of blood sugar.
The guidance from the test centre was to reduced sugar intake, increase complex carb intake and eliminate snacking in between meals. This was a bit of a surprise. I knew I had a bad habit of eating sugary foods, particularly late in the evening. I’m vegetarian and know that I don’t eat enough protein but the recommended split of macro’s above feels challenging as 243g of protein is about 3 times what I was eating and 2.6g per kg of bodyweight, which is at the very top end of most guidance I’ve read.
Key takeaways from my HbA1c test
Whilst I’m not sure about the macro’s guidance from the test centre, my key takeaway is that I have higher blood sugar levels than I should have. I need to take action to reduce this, as it’s going to hinder me losing body fat and is counterproductive when trying to optimise my metabolism for fat burning.
I therefore need to eliminate snacking in between meals, in particular sugary treats. This will lower my blood sugar levels, will encourage more fat to be burnt in Zone 2 training and will help reduce overall body fat.
My DEXA Scan
A DEXA scan is considered the gold standard for measuring things like body fat, bone density, visceral fat and lean muscle mass. I found this really insightful and helpful in understanding my body composition.
The test found that my body fat is 24%, this wasnt massively surprising to me, although my at home body fat scales say it’s 16%, which I never completely trusted. For me the body fat measurement is at the top of the healthy scale for my age. So not great, but ok. More worryingly my visceral fat (the fat around your organs) was measured at 141cm squared, which is considered in the increased risk range. On a positive note my lean muscle mass was above average.
My bone density came up low, this wasnt a huge surprise to me given my age and that I’d spent most of the last year cycling as my main exercise as Id had a running injury. I also haven’t done weights for a number of years.
You can see from the graph above that my bone density is towards the bottom of the range. Meaning I need to bring more load bearing training into my exercise plan.
The DEXA Scan gave so much detail on, it was really useful and informative. I had bought it as part of a bundle with the VO2Max text, which turned out to be a good decision as it helped give a more holistic view.
Key takeaways from my DEXA Scan
The DEXA Scan helped me understand that I need to lose fat, in particular visceral fat. So I need to think about not just macronutrients but also sleep, stress and alcohol consumption. I don’t drink much at all, but I’m not the best sleeper so earlier nights need to be something I bring into my life.
Resting Metabolic Rate
The final test I did on the day was testing my resting metabolic rate. Which is the amount of calories I am using at rest. This will then inform how many calories I need to consume each day to operate normally and give me a perspective on how I can manage my calorie consumption to encourage weight loss.
My resting metabolic rate came out at 2,140 calories per day. With my lifestyle that means I can consume 2,782 calories per day to maintain my weight at it’s current level. To reduce weight I need to either reduce calorie intake to below that level, or increase the amount of exercise without increasing calorie intake.
How I’m using the insights from the test
Doing the tests and getting the results was great but only by taking action and making changes will I improve my overall health, fitness and performance.
The insights have informed my training plan for this year. I’ll be:
- Doing 80% of my exercise as Zone 2 sessions, working my HR at between 115 and 126 bpm. Wherever possible I’ll be doing these fasted, which will generally mean early morning session
- Bringing in more variation in my zone 2 training, such as running and hiking, which will not only help keep me motivated but will also help improve bone density
- Continuing to do one VO2Max sessions per week, aiming to get my heart rate above 172 bpm
- Introducing weight training at least once per week. To improve bone density and increase lean mass, which in turn will help reduce fat
- Defining the key metrics that I’ll be using to measure health, performance and progress. These will be published here when ready.
For my overall health I’ll be:
- Stopping snacking between meals, or if I do I’ll be snacking on healthier foods like nuts
- Changing my macro focus to be based on protein consumption per kg of bodyweight. As well as an increase in good fats and a reduction in carbs
- Reducing overall calorie intake to encourage fat loss
I’ll also be publishing my health and fitness progress on a regular basis so that you can see the impact these changes are having
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