[stephensmith]

Nearing the end of my PhD, I’ve set up my own exercise physiology lab! Whilst the lab was primarily built to inform my nutrition and coaching work, athletes who want to be tested without coaching are also welcome.

Having conducted hundreds of physiology tests throughout my MSc and PhD, I really enjoyed the process and wanted to continue working with and coaching athletes. Over that time I’ve worked with some world-champion motorsport and downhill athletes, cyclists and triathletes, and just worked with the winners of the 2019 Talisker Whiskey Atlantic Rowing Race.

I’ve been in correspondence with Scott, who has welcomed the idea of my lab being Uphill Athlete ‘approved’.

I offer a range of tests including resting metabolic rate, aerobic and anaerobic thresholds, fatmax, sweat sodium loss and body composition. I can also offer blood profiling for hormone and nutrient deficiencies.

Based in Wirral, in the UK. I’m sure I can arrange a discount for UA members!

For more details: http://www.racefaster.co.uk/

Thank you!

Topic

[stephensmith]

stephensmith on February 2, 2020 at 2:02 am #37241

Trying to change my profile picture! Seem to be having some trouble with Gravatar

[Anonymous]

Anonymous on February 3, 2020 at 9:11 am #37298

Thanks for posting. That’s great news.

Question for you: How is Fatmax measured? I’ve read that it doesn’t always correspond with an RER of 0.85.

[depeyster]

depeyster on February 3, 2020 at 3:05 pm #37371

@Scott Semple

RER/RQ gives a ratio of CO2 produced to O2 consumed.

Generally, from the same graded exercise test and metabolic cart that measures your RER you can infer Fatmax.

If you calculate either the fat grams/hour or fat calories/hour at any given HR, you can find the value at which the maximum rate of fat burning occurs. It is distinct conceptually from the metabolic crossover point where there is a 50%/50% split between fat and carb energy. It only looks at the point where the most fat per minute (second, hour, etc.) is burned.

I had a HR of 164 at RER 0.85. My tech and my report did not give me a Fatmax but I was easily able to determine it to be 52 grams/hour at 145 HR (RER=0.76). At RER=0.85 my fat consumption was an even more paltry 38 g/h. (I was eating very low carb, moderate protein, high fat, at the time.)

[Anonymous]

Anonymous on February 4, 2020 at 5:12 am #37389

Great news Stephen, particularly in getting the “UA approval”

Finding labs that’ll conduct testing can be hard. I’ve used Team Bath in the past although that test wasn’t strictly to the UA standard it gave me what I needed to start on the path. Maybe in time we’ll get some form or country based registry in place on the site so places like yours are easier to find.

Good luck in you endeavour!

[Anonymous]

Anonymous on February 4, 2020 at 2:31 pm #37425

@depeyster: I am confuse. Can you show your calculations?

[stephensmith]

stephensmith on February 5, 2020 at 4:39 am #37489

Hi Scott,

Essentially we take the breath by breath analysis of O2 and carbon dioxide, and average the last 30 seconds worth of data from each stage of the test. We then input these values into a stoichiometric equation, which when plotted against power gives us a sort-of bell-shaped curve. Each athlete’s curve is quite different. From that I pinpoint a fatmax zone for the athlete to work within for those particular sessions.

Image attached

Attachments:

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[depeyster]

depeyster on February 5, 2020 at 8:58 am #37496

Scott,

I have attached two files.

In “fat Kcal per h” you can see that at HR 145 bpm, I was burning 492 kcal/h of fat. Since one gram of fat contain 9 kcal approximately, I can divide 492 by 9 and determine that I was burning 55 g/h. This was my highest fat burn rate at any of the measured intensities. Hence, my Fatmax.

Compare me to the elite runners graphed on page 62 of TFTUA in figure 2.10. The low-carb (fat adapted) were burning 1.54 g/m or 92 g/h. I am also fat adapted from eating low carb but clearly very, very sub-elite.

The the “RER” attached file you can see my metabolic crossover point occurring at RER=0.85. This occurred at HR 164 and then later 167 bpm. As you know, above this point, I was burning more CHO energy than fat energy.

So, there are two distinct concepts:

1. The intensity at which the greatest amount of fat is burned (145 for me on this test), and
2. The intensity at which more energy utilization comes from CHO than fat (164-167).

Attachments:

You must be logged in to view attached files.

[Anonymous]

Anonymous on February 5, 2020 at 9:12 am #37502

It’s interesting that fat utilization falls off after the initial FatMax point. It’s too bad it doesn’t flatline and just add carb utilization on top of it (giving both speed and less glycogen use for that speed compared to dropping fat use).

Is there a reason or theory why fat use drops off?

[depeyster]

depeyster on February 5, 2020 at 9:13 am #37503

The FASTER study, referenced on page 62 of TFTUA in figure 2.10, is freely available here: https://www.sciencedirect.com/science/article/pii/S0026049515003340

[depeyster]

depeyster on February 5, 2020 at 9:19 am #37505

Scott,

Great question and I have no idea what the answer is. But the entire UA method could also be viewed as a way to push the Fatmax point at as high and intensity as possible, so as to delay the catastrophic decline in fat utilization.

[Anonymous]

Anonymous on February 5, 2020 at 9:32 am #37506

Thinking out loud…

So if a test didn’t provide FatMax, but did provide average calories per hour per zone, you could figure out FatMax by applying the following formula to each zone:

kcal/hr * [percent_fat] / 9 = g/hr

Then the zone with the greatest g/hr would give a rough idea of FatMax.

@depeyster: With respect to fat burning, I don’t think more is always better. The real metric to improve is the highest average speed over a goal event. Being more fat-adapted may not always help.

I’ve seen very successful ultra runners in skimo races get dropped because they have no speed. The same racer would likely win a very long event, but in a ~2h skimo race they were off the back. That may or may not be because of fuel preference, but I suspect it’s a factor.

[depeyster]

depeyster on February 5, 2020 at 9:36 am #37507

I agree with the formula.
And, yes, I was just thinking in terms of my own goals which focus entirely on months-long durations. It wouldn’t necessarily be desirable for shorter races.

[stephensmith]

stephensmith on February 6, 2020 at 5:37 am #37568

You don’t really have to go so complicated, as your aerobic threshold highly correlates with your fatmax: https://www.ncbi.nlm.nih.gov/pubmed/28745473

I’ve also seen this in my own data when testing athletes to a point where you can pretty much assume the values to be equal.

[depeyster]

depeyster on February 6, 2020 at 7:03 am #37570

@stephensmith,

If you look at my attachments, above, my FATmax (145) diverges nontrivially from my RER=0.85 (164). Which one would you recommend for AeT?

Generally (i.e., recognizing there are always exceptions), on this forum an RER of 0.85 on a gas exchange test determines AeT.

[Anonymous]

Anonymous on February 6, 2020 at 5:20 pm #37658

@stephensmith: I’m curious what those test subjects did for training. They’re all very tall and very heavy (even for their height). I’m going to guess that they are rowers.