• Guest - w'd love to know what you think about the forum! Take the 2025 Survey »

Does anyone have experience with lactate testing for endurance exercise?

Wow, that is a lot of carbs! I've not read that book in particular, though I have read some of his articles and other things on training the gut and recommendations on carbs per hour. 60g/h would probably be calorifically balanced for my riding, and while I could probably eat that much if I tried, I'm not sure I could do it for 10h straight without fail, nor carry enough with me without it all being in the form of gels or drinks, which again aren't great over long durations (at least for me without the hassle of training my gut.)

Really interesting to know what you're consuming though, I can now understand why you have the pre-event bolus.

Regarding salt loss, I used to get cramp quite a lot, I still get it sometimes though much less.

I used to take a bottle with water and a bottle with a hydration tab for 4h+ rides, but when warm and after a fair few hours it's sometimes not really what I want to drink and may be all that I have left. I read an article pointing out that sweat is hypotonic (i.e. has less salt per unit volume than blood), so when you sweat though you lose some salts, you end up with a higher concentration in the blood than you previously had. I'd not really thought about it, but it does mean that you don't need an isotonic drink to rehydrate, which is why I've switched to trying to get my salt from food and just drinking plain water. I do still take a couple of tabs with me just in case I get persistent cramp so I can make up a small bottle.
 
SimonP78 said:
Really interesting to know what you're consuming though, I can now understand why you have the pre-event bolus.
Click to expand...
Interesting new angle for interpreting my data!
My first comment is that we do different types of exercise.
In my 20 s I spent my holidays cycle touring the more remote parts of Britain. A typical day tour could be 130 km and I would spend 8 h in the saddle. (I have 2 custom frames: An Argos of Bristol Reynolds 531 from 1985 and a Bob Jackson of Leeds Reynolds 653 Audax frame from 2000.)

When I got DM1 in 2004 I could not exercise for years because of constant bonking. Apparently too much (endogenous?) insulin in my body.

My present system of carbohydrate loading is optimised for more vigorous exercise lasting 15 min to 3 h. I tried 2 days of cycle camping last year and it went well, but there may be cumulative effects that build up over a couple of days that I do not know yet (I experienced some when I did sea paddling courses to become coach).

When I do triathlon I need enough food in the system to start with. That's my standardized muesli meal. I dose the insulin so that my blood sugar is never lower than 7 after some 45 min (when I come out of the water after a swim) but not higher than 14 (sometimes it is 18). From then on I drink High 5 in an amount that keeps blood sugar above 6.

Take home message: We are all different and you have to train managing your metabolism and your metabolism just as you train your fitness. You need to observe and then make small incremental changes.
 

Allan Hovda (one of Norway's leading triathletes doing Ironman) told us on a training weekend that he eats food packages labeled with gram carbohydrates 60 g per hour or more. He tops this up with water from the food stations. He estimates his water loss given temperature and race profile and drinks the estimated amount of water. He has measured the salt content of his sweat and then eats salt tablets accordingly (if he diluted the salt in the water, the solution would have the same salt concentration as his sweat).

He could of course drink sports drink just like me. The problem is: Then you need to carry a lot of drink. In the context of long distance races that go over many hours, it is better to take with you the solids and add water from feeding stations. It is generally not a good idea to take sports drink from feeding stations - you never know how it was mixed and it may turn your stomach. Only water and bananas are safe.
 
What a fascinating topic. I am 70 years old and keep as fit as possible with hiking and gym. I have managed the gym with no problems. I use Omnipod and Libre 2 and have settings of insulin for all my exercises. However I hit a brick wall when I did the TMB(tour de mount blanc) Although my blood glucose levels were reasonable just a few hypos. I was running out of steam on high climbs. Recovery was quick so I don't think it was general fitness. I wondered if you had any opinion on where I went wrong. the ketoacidosis theory is a good one as I was running on very little insulin (0.05units per hour) and I did wonder if I should have stopped, snacked and taken more insulin on board. I ate when everyone else did
I know nothing about lactate testing. Have you any advice you can give me as I would hate to give up on long distance hikes
 
The is also the Sapiens. That's a Libre 2 sold to non-diabetic athletes under a different subscription model and using different software. Kristian Blummenfelt wears one.
 

Garmin produces loads of data!

Like most triathletes I like to look at my training data, but I have begun to be a little more relaxed about them. The main issue is to avoid overtraining. I try to listen to my body as much as I can. My idea is to use objective data to calibrate my listening.

The point is: None of these algorithms have been validated in prospective randomised trials.

The Garmin running lactate threshold algorithm is based on heart rate variability - that is not % of maximum heart rate or lactate threshold. All of these parameters measure things that are closely correlated but not quite the same. An alternative to formal lactate threshold testing with lactate measurements is to do an all-out 30 min time trial on the bike (as promoted by Friel). But: How do you pace yourself correctly? And: This will stress you like a competition. Is this amount of stress outside a competition worth the information gained? I think not.

I monitor my performance closely but with the primary aim of avoiding overtraining, not to intensify my training. The rest is consistency. I fulfill my training plan week after week unless I am sick.
 
I find the overnight HRV number quite useful to judge whether I've had enough rest, I also find the lactate threshold number seems to be about right (at least as a proxy for a HR I can maintain "indefinitely") - I did a 5h30 ride last year and I was going about as hard as I could manage (time pressure, weather turned and then an endless headwind) - I foolishly thought I'd try to get the ride done and dusted as quickly as I could, as it wasn't very pleasant, rather than chilling out and going a bit easier.

My average HR for the ride came in a couple of BMP under the number Garmin thought my lactate threshold was. It was a mistake to go that hard for so long, I was wiped out for a week.
 
To throw another thought into the mix, I find I have significantly less endurance at higher efforts and can't achieve high powers for long at all (cycling that is) when running down close to being hypo - I can still keep turning the pedal even when actually hypo (as long as I'm not so low that I'm going to fall off), just can't maintain any power, so hills become rather a challenge. I try not to be there, obviously, but am sometimes and should probably have a dig through the data to see if I can tease out any relationships/see how quickly I recover after eating something and my BG rises - I wonder if there's also a longer term reduction in power even once a hypo is treated, as in normal life one can often feel the after-effects some time later.

Out of interest were you doing fingerprick tests or using a CGM or treating based on how you feel?
 

Interesting observations! I fitted Garmin Rally Keo power pedals to my 2 road bikes. With the xDrip data field for my glucose from my Abbot Libre 3 I get all data into a neat diagram in Garmin Connect. So your problem can be solved! It is just that power pedals are rather expensive...
 
SimonP78 said:
It was a mistake to go that hard for so long, I was wiped out for a week.
Click to expand...

That's why taking a 30 min time trial at maximum steady state effort for the sole purpose of estimating one's lactate threshold is not a good idea. I reserve this kind of effort for competitions (which makes the data from competition so interesting.)
That's why actual lactate measurements are so elegant - you don't need more than 6 minutes' effort at maximum intensity to establish your threshold, at least as a non-diabetic.
 

Google came up with a new advertisement just for me: A continuous ketone monitor:

SiBio KS1 Continuous Ketone Monitoring System (CKM)

Track ketone levels with ease using Continuous Ketone Monitoring (CKM). Painlessly wear for 14 days, new readings every 5 minutes.
www.sibiosensor.com
The advert looks serious enough, but I would wait for reviews before buying it. I am now in the tail end of my yearly training cycle (1 triathlon sprint remaining), so it's too late for trying this season.
 
I have a single sided crank arm power meter, mainly as I was riding flats in the winter (and also pedal strikes while riding a gravel bike), I need to actually sit down and write some code to do the analysis without getting distracted!

Agreed, however Garmin had already decided what it thought my lactate threshold was based on normal riding around. I agree that an actual blood test measurement is going to be the best way, I was just commenting that in my case Garmin seemed to get it about right (sample size of 1 of course, so who knows! )

Yes I saw that too. I'm sure I read a review somewhere too - I'll have a look and see if I can find whatever it was I was reading.
 
I found this review on hand-held meters. They are reasonably cheap (cheaper than lactate meters and testing strips)

Which is the best ketone meter on the market? – Diet Doctor

Top ketone meters… Who needs one? You might. Are you in ketosis? With a blood ketone meter, you can test for blood levels a ketone that your body produces when in ketosis.
www.dietdoctor.com
Probably a better option than a continuous sensor. I am very dependent on my Abbott Libre 3 CGM. I already had a reproducible reaction against the glue of the Libre 1, so I don't want to try fate by gluing another sensor on my arm.
 
Certainly cheaper as the strips are available on prescription - I requested a meter (and some strips) for the first time ever for just this purpose, I don't recall when I last tested for ketones, but it must be more than 30 years ago though.

I've yet to get around to actually testing though - the strips are quite expensive (to the NHS) and there aren't many in a pack so I wanted to come up with a plan rather than just testing at random, which means I've still got an unused meter and pack of test strips!

I personally think continuous monitoring would be a better bet (notwithstanding potential issues with allergic reactions) - I could see it being pretty easy to get a full suite of data from a fortnight's worth of monitoring normal life plus some endurance work, hour-long sprint (on the bike) work, and some mixtures so see how/whether there's much of a change.
 
I decided a pedal power meter was easier to move between bikes, but in the end I equipped both bikes with a Garmin Rally RK 100.

I would expect that all surrogate measures of functional threshold are somehow correlated - be they based on actual lactate testing (gold standard in non-diabetics; I am unsure if it works for me), maximum heart rate, heart rate variability (Garmin running lactate test with pulse belt) or a time/power plot. This is why it is difficult to say what is actually best! I am beginning to be sceptical - there is a huge industry living of this.

I can't make much sense of Garmin's lactate thresholds plotted over time. However, their estimated VO2 max for cycling and running plotted over time corresponds very well with my subjective improvement in cycling and running over the last year.
 

I successfully re-engineered the TaiDoc meter. Each batch of strips (be it lactate or ketone) comes with a coding chip. The chip contains a batch specific number such as 180, apparently for calibration. However, it also contains the batch's expiry date. If the batch is expired, you will get error E8 - expired, and the meter will not accept the code at all. The solution was to set the meter's clock/calendar back by a year. After this, the meter accepted the code and I could measure my serum ketones.
 
Time for me to report the latest results. I concluded the season with the Triatlon Sprint at Os on 10 Sept 2024. This year it was cold and raining.The transition zone was a mud bath. So I was 2 min slower than last year

My total was 1:31:04 h (2022: 1:29:08): 18:43 for the 750 m swim (2022: 17:39), 41:01 for 19 km bike (2022: 39:48) and 25:43 for the 5 km run (2022: 28:05).


My bane is Dimitrios. He is M60 and aims to be one of the 15 best in the world in long distance triathlon. He is a much better swimmer. We both used road bikes, and I was on 10 s slower. But my run was 22 s faster!

I attach some readouts from Garmin (using Rally power pedals and a Pro pulse belt) since they give an indication of my functional thresholds.

One week later I took full performance testing at Stig at terskeltest.no... This will be my next post.
 
Stig at terskeltest.no knows his stuff. He sent me instructions a week before. I was forbidden to train the day before the test. I needed to take the bus as I was to warm up under his supervision.
On Monday at 8:40 we tested my lactate threshold for running and then my VO2 max. On Wednesday at 9:30 lactate threshold for cycling. We fitted my Garmin power pedals to his ergometer bike, so we have comparable measurements.

I got up at 7, injected 2 units of Novorapid to cover the dawn effect and then had breakfast on his premises (120 g muesli on Monday, 150 g on Wednesday) plus 9 units insulin 40 min before exercising.

I got completely normal lactate curves! We compared our lactate meters, his values were 70 % of what I get on my meter. I asked him to keep measuring my ketones with my meter - all ketone measurements were negative on both days.

So my suspicion that lactate testing does not work in DM1 is unfounded. However, my ketoacidosis theory is not disproven as yet - I have to a lactate test when I am way too hyperglycaemic due to overaggressive carbohydrate loading.

Here are the results.

Running Woodway 1.7 % incline



The key numbers (I translated Stig's summary)

LT-1 - Aerobe threshold – green zone - (endurance): 120 (range 120-131)
LT-2 - Anaerobe threshold– orange zone - (performance): 152 (range150-154) eith 3,3 lac – threshold pace 11,7 km/h, 5:07 min/km on treadmill with 1,7% incline
Maximal oxgen uptake- Vo2max: 52,0 ml/kg/min- excellent for M60.
Vo2 threshold (Lt2): 32,4 ml/kg/min (utilizaton 62,3%)
MaxHR 172 (outdoors you can come up to 175)

Cycling


Aerobe threshold (LT1) (endurance): HR under 120 (range 110-120) og 145-175Watt, at 1,4lac.
Anaerobe threshold (LT2) (functional threshold): pulse 141 +/- 2 pulsslag (range 139-143), 237W, at 4,0lac.

That wasn't too bad, was it?
 
Hi @marty313 , most of what you write flies right over my head but is looks like you're doing really well!
I just wanted to alert you that your full name is in the screenshot in this post, and it's very easy to find you on the internet. https://www.diabetes.co.uk/forum/th...ng-for-endurance-exercise.198605/post-2644318
No problem if a conscious choice, but if not, you might want to crop your screenshot a bit for online safety reasons.

Good luck, and keep posting your results. I think it's very interesting even if I don't understand half of it.
Are you only testing for yourself or are you planning to publish about it?
 
Congrats from me too, very impressive performance

Thanks for the graphs, I'll have a proper look through over the weekend but at first glance I'm curious about the lactate readings for incline running vs cycling, there's a factor of ~3 difference as well as a slightly different shaped curve - are these expected?

I suppose the difference is down to how much muscle is working, though I always thought that running worked more muscles, though I've no idea where I got that impression!
 
You must log in or register to reply here.
Menu
Log in
Register
Cookies are required to use this site. You must accept them to continue using the site. Learn More.…