As a guy who teaches renal and cardiovascular physiology at a medical school, I totally agree with all of this. So much of it depends on the conditions. A key element is that whenever it is harder for your body to maintain a body temperature in the face of stimuli that want to increase it, then the heart rate will increase for any given power output. This is because the heart is going to have to pump more blood into the skin so that you can radiate heat and that means less is available to power the muscles. It's as simple as that except that that means it's not very simple. The complexity is that there are many environmental factors that tend to make your body temperature increase. Your body will gain heat as a result of convection (how hot it is outside), through radiation (shade or direct sunlight), and through heat generated by muscular exertion and other metabolic activities (your power output). If it's very hot outside you gain more heat through convection (and lose less through breathing). If you're in the direct sunlight, you gain more heat through radiation. If it's very humid outside, the efficiency of sweating as a mechanism to lower your body temperature becomes much less effective. Actually if you are a very fast cyclist then the air moving around you will help with that. I live in Houston so those are the things that mostly are on my mind, but altitude is also an issue. When it's really hot outside, you should rely more on heart rate and RPE because if you don't you could get yourself into trouble; and that is assuming that you are staying on top of hydration and electrolyte input. Obviously your body can heat adapt, but not enough to fully compensate when the temperature is above about 90 and the humidity is high. Before you're fully heat adapted the effect on heart rate is much greater, but no amount of heat adaptation is going to fully eliminate that effect,. Once you are heated adapted the combination of heart rate and RPE is probably the best measures of how hard you are actually working. I'm talking in all of this about pacing a ride, not so much about interval training, which is an element that I know much less about. Although some of the same elements are going to come into play even there.

I have been cycling for my entire adult life and now that I am older I've had to back off the intensity. When I was younger I could go out and smash it all the time and recover quickly. Now it takes me days to recover from a high intensity ride. It's been a hard lesson to learn for me. Getting old isn't for sissies 🤣. Now I do a lot more low intensity work using heart rate. This has helped so much! I do one ride a week, usually with others where I hammer the rest is LSD, long, slow, distance with a low heart rate. Everyone is different but this works for me 😊

I really like how someone who has the level of expertise that Stephen has still has an approach with a fair bit of "you know, if you're more or less doing this, or listening to this feeling, you're on the right track". Takes a lot of the stress out of trying to get it perfect.

Back when I swallowed the power pill, and I used to train to power, I was always uneasy about training to an output. It never really felt right. Heart Rate, whatever the conditions is a direct physiological measure of your response to the effort. Power is just the output that your capable of in those conditions. Its only really useful in comparing yourself to others. It’s always struck me as odd to train using a variable output measurement rather than a direct physiological measurement. I can tell you this, after switching back to HR based training, as I get older, I enjoy my training much more and am better at listening to my body, and I don’t overtrain anymore….but I’m just another sad old MAMIL, so what do I know….😊

Really like these series. thanks!!

Fantastic content as always! Like hearing to seminars

This was excellent. Thank you so much for putting it together and sharing!

Excellent interview.

Thank you for this Dylan!! I appreciate the knowledge!

Great series - thanks for the content.

Great videos, Dylan. Thanks.

More excellent content with Dr. Seiler. Thanks for bringing this to us, Dylan.

Great and insightful video. Thanks so much Dylan and Doc 👌

Brilliant. Thanks for doing this.

As always, another quality video with useful information. Thanks heaps guys.

Damn this video, the answer i have been waiting for for 2 years. Thanks a lot Dylan

Love the insights and science based approach. Keep up the awesome videos.

Wow Dylan, that was such a great video, so insightful, big thank you to Dr Seiler. keep up the great work Bro!

This video is so good! The whole series is great, but this was my favorite. Thanks for sharing!

Two of the best videos yet. Really enjoyed the thought process. Has me thinking about how I train.

Thank you for this. Great stuff

This was great. Not sure if I enjoyed part 1 or 2 more. Hoping there’s a part 3 coming!

Great content as usual!

That point on focus versus distraction, and appetite being an indicator of effort, was super insightful!

Best video on training intensity that I have ever seen, good stuff! 👌🏻

great editing, audio and video. Actually helpful graphics and some nice shots to break up the talking.

Thanks Dylan! I would love a video on best resistances / weighted exercises for IN season, just like to go to the gym twice a week in season but find it often burns my muscles, thanks again!

I am a 63 year old cyclist-XC skier. I am amazed at how training techniques will come & go according to the flavor of the moment. Watts-HR-lactates-Tabata-8min. Been there done that. I have done away with all the gizmos, I just go by feel, good day-OK day-bad day & adjust accordingly. As the Doc said, listen to your body, perception of your efforts is where it's at !

Excellent video, thank you. I especially like the concerted effort into trying to answer key macro questions that are applicable to a great many athletes. Even to us 'over the hill' Masters!

Tried a low intensity ride yesterday (first time pretty much ever) at roughly 60% of my HRmax. Lots of discipline needed cause people were overtaking me left right and center. Seiler talks about that testosterone driven response in situations like these and I can tell you it's hard to resist not to counter. Next time I'll wear a sign "low int ride today" or sthg like that

That was excellent. It's not an easy answer, so you need to be listening carefully and you have to apply these ideas to your goals and particular situation. Thanks for a great training lecture!

Fantastic conversation

I can't express the satisfaction I had listening to Dr. Stephen! Thank you for this video Dylan!

As always, you any Dr. Seiler are spot on. I wish there was a little reiteration of HR vs. LT1 and LT 2 for clarification of where drift occurs. I believe he touched on it in his last video, but I know he goes in depth on his channel.

absolutely fantastic! Thanks!

Awesome content that calms me 49years old dude down and confirms to me what I do isn't so wrong, regards from GER

Listening to Dr Stephen Seiler's talk was both interesting and informative . Great content .

Excellent Info ! 👍

Dylan's training plans are awesome, I used them to finish Unbound 200 twice.

Solid…Solid stuff Brotha! Thanks for continuing to put forth real, frank information for the little guy and everyone about!

So on point. Two days after this video, on July 4th, the Giro d'Italia Donne had a very hot day of 35C/95F. American rider and GC contender Kristen Faulkner blew up at the base of climb 3 of 4 because, as she mentioned on Strava, she was dehydrated and setting several personal highs for Heart Rate.

Just wanted to say how much I love your content. I'm not the best cyclist but I really like to dig into these types of technical details. Keep on the great work.

I'm glad he mentioned the brain 'zeroing in' on other things when we ask effort from ourseleves. There are things going on in our mammal bodies that we are never aware of. Some things we are, like pain, heart rate and breathing.

I now know why im always so so so hungry after low intensity sessions, always wondered why my appetite is so high. Also learnt that low intensity sessions that go for long durations can turn out to be high intensity without knowing, keep an eye on the heart rate.

Man, thank You so much for this. It makes a ton of sense. I realize I have made a lot of training mistakes, burning out quickly, not enjoying riding anymore

This is a great video!!

Excellent and informative. Keep up the interviews with differing authoritative voices, and don't hesitate to keep it geeky!

Good questions Dylan, it starts to expose the hype of the industry.

Dylan, thank you also for the weightlifting reference, great insight as a strength and power athlete (football) growing up, the stepping up weight then reducing the reps analogy is perfect. I always was thinking there’s something completely different about endurance training than strength but they have very strong correlations. I’m glad to reconnect with your knowledge pipeline after a long break (literally broke my leg last year and back on the trail for 6 weeks so far this year). You continue to inspire on Strava and educate and entertain online!

Dr. Seiler has a killer chart/metric where he divides 6min power/%HRR and for long rides you can see where things started to fall apart. I created a graph for it on Training Peaks. Super helpful. Also made polarized by HR vs polarized by PWR charts which is really interesting to watch over the course of a season. (For me, the more fit i get, the more those come into alignment where time spent below LT1 HR starts matching time spent below LT1 power zone. Before fitness my heart rate indicates above LT1 while my power indicates less than LT1.)

this is golden info!

this was very enjoyable.

very informative interview for a free KZfaq channel. thank you.

Great video.

Nice use of clips to spice up basically a Zoom call. Thanks Dylan

Temperature too. at cold temperatures your drift may not occur at all until 3 hours in at 200 watts. at 30 degrees C you might start drifting after an hour at 200 watts. so as well as load and measured stress the involvement of external temp will also hugely effect the boundaries shifting.

A good follow up video would be to delve into DFA Alpha 1 as a training tool for low intensity riding.

The point at 10 minute mark is very important for me. I have 55bpm resting heart rate. Yet my heart rate went over 200bpm on some hard rides (some even went over 210bpm). This point means most of the heart rate guideline I've heard so far need to be recalibrated for my high range heart rate. I don't know how long I've been wrongly assumed my heart rate zones for endurance training til now. Thank you so much.

i so love this channel

Thank you ☺️

This was really a good video. I am a 65 year old rider who really has a hard time riding at low tempo. I need to get better at this, and this video I will watch more than once.

As someone who is also largely a runner, we primarily train zones based on heart rate because accurate power meters for running aren’t common. As highlighted by this video: Equal power does not mean equal effort (heart rate) > particularly as you get into longer durations.

A lot my buddies think I’m crazy because I focus more on HR than any other metric. Focusing on the intensity my body is exerting is a much more productive measurement than the wattage IMO. I have a power meter but I could actually do without it. I generally only look at power numbers after the ride. External factors that effect heart rate only make the argument to focus on HR stronger.

I like how to explains at as the relationship b/w internal workload vs external workload....

i doesnt matter what power your putting out when your at your max heart rate, thats it, thats what you got, give or take a couple beats

Excellent series. 12:24 I noticed this on my last ride, trying for a lower heart rate I found myself thinking about life, exacting what I don't want to be doing, and the opposite reason I am on the bike in the first place, I had to really try and focus on pedaling technique, and trying to find new ways to get an even better pedal stroke, and bike control, I think there is even more to be gained while on the bike at low intensities because you can switch your training focus to things like: riding with one leg, air pedaling without being on the pedal with one leg while coasting (see how bad your pedal stroke really is!), balancing on the pedals with little weight on hands out of the saddle, coasting both left and right foot forward, turning hard between objects on the road, stretching and being comfortable having the bike move under you out of the saddle, finding the rhythm of the bike while you pull the bars like a sprint without pedaling while out of the saddle (think BMX sprint, you will feel the sweet spot if you get it right), using flat pedals, etc.

Cardiac drift can also be down to dehydration especially if you're on a turbo trainer for 2+ hours. Also, if you ride in the morning there's a good chance you start the ride fasted then begin eating after 30 minutes, 60 minutes etc., the digestion of the food you consumed will raise your heart rate.

As a newbie cyclist these videos are hugely informative. Really enjoy the channel buddy. Keep up the awesome work

Ive noticed this disparity with training times during the day as well. I tend to have a lot more room to push wattage in the morning if im measuring z2 from hr, but in the afternoon/evening z2 is more matched between wattage and hr

Excellent discussion. If you wanted to do a longer zone 2 ride, seems like it makes sense to lower the load each hour. Like in the example he gave for himself, start at 200 and maybe lower the watts 10 per hour. That might keep the stress relatively constant.

Very helpful 🚴🏻

Your heart never stop working. You will know when it does. If you want to target 300w effort. It will come down to if your heart can sustain this effort. Meaning pump the blood needed for this effort. Everything comes down to your heart.

I got a power meter for my indoor machine. It showed something. If I rode with a good resistance and low cadence

Great point about not hammering every day, something that most amateurs probably don't do enough ...

Great channel. Dylan, Dr. Seiler speaks of HR reserve and Max HR, I wonder if these two reference points should be both taken on the bike? (For karvonen formula), consider that taking rest hearth rate while laying down or being on the bike can give quite different results. We can notice a difference even while seating on a chair compared to seating on the bike due to the different body position. While for the max heart rate test, I have found that it can reach different values according to the methods, eg. riding the bike with dedicated method or wiring on an elliptical trainer when using also the hands for moving the machine, generally Max HR is higher in the latter. Appreciated your comment here.

When will we get a video discussing gear choices? 1x vs 2x? How you decid on chain rings? ect...

I've always found my HR the best indicator of training/fitness. Good to know that my HR based threshold efforts are the best way to start before zeroing in on an actual FTP number. I like to do 2 x 20min @ 176bpm (my max HR is 191).... And let the power fall wherever. Then use those FTP numbers moving forward

Hello, Dylan. Thank you for your great job! Can you make a video regarding riding outside or doing it with smart bikerack (Tacx or any).

Excellent

You're right on target with this discussion! Thanks so much for these super informative interviews. I'm not a racer. I just enjoy long, low intensity rides. I find myself doing very well on these, rides up to about 2.5 hours, then my heart rate starts gradually creeping up towards my LT. Up to around that ~2.5 hour point my aerobic decoupling is very good. But the longer I ride past that point the worse the overall aerobic decoupling for the ride becomes. If I stop before this point it looks like I had a great ride, but if I go for another couple of hours that changes completely. Did I over-do it, or is this good training?

Very interesting Dylan. I periodically test my fitness by measuring my power output at the end of a 1 hr turbo ride whilst keeping my heart rate strictly below the max for Zone 2 (5 Zone model). A good result for me is 165 Watts with heart rate throughout the ride held at 145 bpm (vs max 186 bpm). During the hour I have to back off my power to keep my heart rate at the 145 bpm max. After an hour the final 5 minute average power number is the result I'm looking for (no sprinting at the end!). I then plot the results over weeks/ months to see trends. If I've been off the bike for 2 weeks or sick the loss in performance is very clear and measurable in lost Watts. It's easy to ride at Zone 2 for an hour so this test is much less painful than an FTP test.

Top content

Excellent topic and content. Definitely sharing this channel and video with many fitness friends and cyclists. Thank you! 🙏☀️🚴🏼‍♂️🚴🏻‍♀️

Thanks for this video Dylan and great knowledge guest I find this and the sceience very interesting and would like to apply it. I have now since on my garmin made adjustments to be set to heart rate reserve % and I did also know my correct max and resting. However this has now brought my zone 2 every day base rides topend 16 higher than before and also matches what I had set my running zones to now. Had I been training slightly under in general on the bike also I always tried and thought I should be training at lower hr for my cycling than running (non weight bearing, I may also may well be a better runner too however if not currently or for 3 months, now full cycling training instead ).🤷 What do u suggest keep the great channe many thanks Jon

I thought what Stephen said made perfect sense though I could split my head open before getting TrainerRoad people to understand that science supersedes business model ( And believe me I’ve gone at it with Nate on topic to no end!) regardless! My favorite parts of your back and forth is your brief synopsis after point that sums up for those who might have never heard the knowledge! 💕🚴🏼✌️

The only metric I pay attention to is heart rate. Why? it determines how well rested we are and really hard we are pushing it. It is called a red line for a good reason.

I have many friends around who bought powermeter and within few months they overtrained heavily. Z1 or Z2 zones are great info, but these zones do NOT work for unlimited time... You must watch your HR and total time. Everything must be done gradually. And Z1 zone does not mean your NP from whole ride is in Z1 range. Your whole ride must be in the right zone, all the time. Otherwise it is not easy Z1 ride :)

Incredible info there! Thanks! A question I have difficulties to answer : can you go too low on a low intensity (and long) ride?

It would be nice to see video about what really good cyclists have done at beginning of their careers when they propably have make the best gains of speed etc.. Just the facts! There were time before the watts or heart rates, and cyclists were quite fast!

My HR reserve is 141, so I calculate 141*.0.55=77bpm +39resting HR equals 116bpm 65% is 130bpm. I used to use 142bpm for Z2. It looks like I've been over doing it with steady rides

This video is helpful and give a lot of ideas, thank you

Great vids! What do you eat before, during and after 1.5-4 hour zone 2 rides?

What a beautiful video man this clear lot of things going on in my mind love u man . This video will help me in long run . I am 3 years into cycling n now always tired n pain every where becz i was try to get my hr above 180 but now my resting is 42 n max is 170 so now i will train different after listening this .

There's a typo in the title, buddy. You do great work, Dylan.

Dylan when he talks about percentages of heart rate reserve hes essentially talking about the Karvonen formula right ? Thanks. Great channel !

Thank you for your content. Some suggestions: Can you please add some conclusions in an easy (text) format (for not English followers). For example, in this video, I do not sure what I should do when I ride base after the 3rd hour, lower my power and keep HR as it was in the first hour, or just continue to keep my power?

Just one comment - Heart rate reserve is not immune to weather conditions. 60-65% of heart rate reserve as a low intensity session is quite challenging for high humidity high temperature conditions and therein, you start to disconnect between heart rate and external power or pace. There is a definite duration impact on the rate of this discconnect appearing (obviously starting out is less of a concern than the last 3/4 of the session)

Shout out from Philippines

Hi Dylan, how can I purchase a Jukebox cycling jersey? Thank you

Would be nice it were possible to set one of these apps to fix output downstream of heart rate