Aerobic Fitness Blood Test

Hey Guys and Gals,

I am new to the whole QS movement. I have just started to get back into working out and running. Are there are any markers of overall aerobic fitness that I can have done in a blood test? I am not thinking of lactate thresholds/V02 max but something that I could get done by my doctor or at Qwest.

I want to be able to track now and months from now to see how I am doing.


I’m not aware of a convenient marker for aerobic fitness, unless you are talking about this :wink:

urine amino acid test can tell about aerobic fitness. It is usually done to detect metabolic disorders that lead to increased amino acid levels. Reduced excretion of amino acids, on the other hand, is associated with increased aerobic fitness levels.

Blood and urine metabolites related to energy production could be also used as indicators of recovery after intense exercise.

Biomarker that Segterra found affect athletic performance include iron levels and Vitamin D

You can get a pretty detailed blood panel with their InsideTracker service, which uses QuestDiagnostics. I reviewed insideTracker twice; PM me for a discount code for QSers if interested.


I’ve not used these but here are:

23andme says about me that:
George, your fast-twitch muscle fibers likely do not have the alpha-actinin-3 protein.
Not sprinter/power muscle type

Personally the best bang for my buck has been to use TRIMP / Coggan models that underlie TrainingPeaks and 2Peak (I use 2Peak). I am also using another mathematical model of my fitness Xertonline.

These tools model your fitness / recovery and guide you through periodization of your training. For endurance athletes management of Training Load (stress) and recovery is key to fitness (Super compensation Principle, Overload Principle).

For cyclists, the key measure is Watts at the pedal vs your FTP (max sustainable Watts), for runners and swimmers (I am not one) I believe they use your HR versus your max HR to measure training load. In all cases we apply the Super compensation principle ( and periodization.

If you want to train systematically for running/swimming/cycling there is a lot of sophisticated approaches and some tools such as the above which require devices from Garmin, Polar and the like. Also there are a lot of easy to find free training programs you can follow.

Hope this helps!



Don’t know why I didn’t think of it but you could use Heart Rate Variability. Its non-invasive. (Obviously your resting HR will go down as you get more fit - I’ve dropped mine 20 points but it took a few years for that that).

There is some evidence that the inter beat variability of our heart rates reflect stress as mediated by the parasympathetic and sympathetic nervous system which separately enervate our hearts. Variability is affected by the degree of activation of the two systems according to the theory. Sympathetic nervous system arousal results in a more regular heart beats. Parasympathetic dominance results in a more varying heart beat as the respiratory sinusoidal rhythm slows and speeds up the heart. So in theory the balance between these two systems appears in the regularity of the HR.

As the holy grail of exercise is to load the body (stress) thereby triggering adaption and then recover (adaption phase) in theory we can use the HRV to measure the amount of stress (exercise load – estimated in techniques like TRIMP/Coggan above) and then see how recovered we are.

If you have an iPhone and HR monitor (e.g. Wahoo HRM) that can do R-R recording you can use the HRV4Training app. There are others but I like this one

This technique has not worked so well for me – but YMMV.

Good luck!

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I would look at BRS - baroreceptor sensitivity - you need continuous BP, but several devices do this.