The most important number for your health (feat.

Go check out my chat with Dr @MedlifeCrisis: • How to Prevent Almost ...
The most important number for your health is how you feel. Hang on, this is a science channel, not an Instagram account for motivational wellness quotes. Let’s take a data-driven look at the numbers you can get from a smartwatch or other wearable device, and find out which is the most important one to optimise your health.
This video is part of my series on smartwatches. Go check out the rest of the videos in this playlist: • Smartwatches series
Chapters
00:00 Introduction
01:03 Resting heart rate
03:08 Exercise heart rate
05:47 Steps
09:30 VO₂ max
13:31 The best thing about wearables
15:03 Rohin’s most important number
16:35 Andrew’s most important number
Sources and further reading
Resting heart rate
Risk of death, cardiovascular disease and cancer vs resting heart rate pubmed.ncbi.nlm.nih.gov/28552...
Exercise heart rate
The previous video in the series in which I tested watches’ performance during exercise • Can you trust your sma...
Steps
Step count and all-cause mortality, including evidence for 10,000 steps as a goal, and analysis of ‘purposeful’ and ‘incidental’ steps jamanetwork.com/journals/jama...
The same group found that doing more steps also reduces your risk of dementia! jamanetwork.com/journals/jama...
VO₂ max
Meta-analysis of VO₂ max in consumer devices link.springer.com/article/10....
Fitbit Charge 2 VO₂ max accuracy journals.lww.com/acsm-msse/Fu...
Garmin Fenix 5 VO₂ max accuracy scholarsjournal.net/index.php...
Change in VO₂ max with age via
www.ncbi.nlm.nih.gov/pmc/arti...
And if you write VO₂ max as ‘VO2 max’ or ‘VO2max’, this line hopefully means you’ll still find this video!
And finally…
Follow me on Twitter / statto
Follow me on Instagram / andrewjsteele
Like my page on Facebook / drandrewsteele Follow me on Mastodon mas.to/@statto
Read my book, Ageless: The new science of getting older without getting old ageless.link/

[@DrAndrewSteele]

Thanks to Dr Rohin Francis aka Medlife Crisis for the chat! If you’d like to watch us trade places (we literally swapped seats), there’s a video over on his channel where the doc interviews me about ageing biology. Check it out: kzbin.info/www/bejne/opyoeamJjMqAsLc And hi to anyone from Team Crisis finding this channel for the first time! I hope you’ll smash that subscribe button because I know how much you love following health influencers like me and Rohin.

[@MedlifeCrisis]

Subscribe you cowards!

[@Portia620]

I had many centurions in my family on the side and they walk that’s all they did was walk because their jobs were farmers. They were also out nature state food that they grew and so the foods were Whole Foods so their mental health was better being out in nature, they also drink tea, plain regular tea with sugar, and some of them drink some coffee, some of them smoked in the early ages and gave it up and some didn’t drink anything at all

[@sciencefliestothemoon2305]

Question on the nice graphs for the steps, but is the grey area not the confidence interval, and if yes, that would mean not that we do no know what is going on, but the confidence in what would go on goes down. Also, the widening intervalls would mean, less people out of the participants fall into this area, with many people managing 100 steps, a bit less 5000, and decent chunk less 25k.

[@DrAndrewSteele]

@@sciencefliestothemoon2305 Exactly the right interpretation! We’re not sure what happens, best guess is not much, and the reason is that only a handful of people do 25k steps every day.

[@sciencefliestothemoon2305]

@@DrAndrewSteele those lazy people.😁 Would be great to get a larger sample for the higher step group. Biology has a habit to U-curve on the extremes.

[@rameshchennai6746]

Medlife crisis fans representing 👍🔥

[@DrAndrewSteele]

Add me to the list!

[@MedlifeCrisis]

🙌🙌

[@olommentes]

​@@MedlifeCrisis Possibly the strongest moustache game in the yt and medical community as well.

[@CED99]

That's quite the moustache

[@LeoStaley]

Only reason I'm here!

[@alanmalarkey]

I am 74 with a resting heartrate of 55 doing about 600 mins cycling / week split equally between zone 2 and above. Favourite Garmin stat is fitness age at 61.5!

[@DrPingn]

My resting heart rate is 49 average over a year and my sleeping average is 43 and dips to 36 when sleeping. I cycle about 5 hours a week on average mostly high intensity. But when i used to vape my resting heart rate was 63 and i still did the same amount of exercise then. If you use nicotine daily and care for your health, you know what to do

[@psisteak4122]

And after you switched to cocaine, did things get better 😀 ?

[@someguy2135]

Or, rather, what not to do!

[@ReflectedMiles]

He didn't cover what actually begins to happen down in the under-40 club. The lowered risk starts going away rather quickly, sometimes requiring monitoring / intervention in highly-conditioned athletes. The body really doesn't like that state of affairs, either. The old conventional wisdom about "balance in everything" remains excellent advice, and maybe even more so in a world highly influenced by the nut-job voices in social media.

[@niklaskari]

My Apple Watch 4 consistently estimates my VO2max to be below average, at around 35, which is weird since I exercise quite a lot. Then I did a proper VO2max test and my result was above 50. So yes, those wearables' VO2max results can be quite off the mark.

[@Fridelain]

Shave your arms where you wear the watch and wear it higher on the arm

[@niklaskari]

@@Fridelain Thanks for the tip!

[@cyc00000]

Nuts, 50 is still pretty low for a fit person, but yeah thats way out.

[@wiadroman]

@@cyc00000 No it is not, 50 is a good VO2max. According to wiki "The average untrained healthy male has a V̇O2 max of approximately 35-40 mL/(kg·min).[11][12] The average untrained healthy female has a V̇O2 max of approximately 27-31 mL/(kg·min)." Don't confuse the VO2@max numbers for genetic elite from Olympic Games with what 99% of population is actualy capable of.

[@briandriscoll1480]

@@cyc00000 Not so for an average person, particularly above age 45. By all charts, 50 is considered fit for men at almost any age. For an athlete, yes it's low.

[@drescherjm]

At the age of 51 my resting heart rate is in the 50s. I used to see high 40s about 3 years back but that not the case now. I do cardio at least 3 days a week every single week since mid February 2015. Which was the year my father passed away from diabetes. Seeing all he went through his final year from surgeries, amputations, dementia .. was what got me started and kept me going.

[@DrAndrewSteele]

Very sorry to hear about the source of the motivation, but great to hear about the end result. Keep up the good work!

[@drescherjm]

@@DrAndrewSteele Thanks. It has been a long journey between cardio, diet changes & work to improve sleep. For anyone who has had a similar experience to what my father went through (or other health condition that scared you) my advice is the changes you make to improve your health will not happen over a short period of time. If you try to make too many changes at once you make it too difficult to be able to accomplish your goals.

[@DrAndrewSteele]

@@drescherjm I think this is great advice, and applies beyond the realm of improving health too-doing too much at once and therefore failing at all of it is seriously demotivating. Having the resolve to make lots of small changes over a long time can have its challenges too because it can feel slow, but probably has far better results. Great to have some motivational reading in the KZbin comments for a change. :)

[@choirgrrrl1257]

I'm 63 and spend about 11 hours a week at the gym doing a variety of aerobic, core, and strength classes. Plus I take frequent brisk walks of anywhere between 2-5 miles. I don't have a wearable and don't have a particular desire for one. All I know is I feel effin' fantastic. I have no idea what people my age mean when they say they feel old. I did just take my resting pulse rate and it was 59 bpm. It would be cool to know my VO2max, though.

[@naturesoundsvive7908]

Love youre content, watching it here frome mexico!!!! keep doing more please!!!

[@DrAndrewSteele]

Thanks!

[@dwyt]

Amazing video. Thank you for putting so much work in and making things clear

[@DrAndrewSteele]

Thanks, glad you enjoyed it! :)

[@peterpayne2219]

Excellent video! I was just obsessing over my resting heart rate this week.

[@markmacfarlane3169]

How did I not know about such a great and well put together channel? ❤

[@Marinescu87Dan]

Excellent content, thank you !!

[@LasseBuck]

Interesting angle to using fitness devices👍 We need more studies, but no doubt sleep quality is extremely important for our health! If you are serious about pulse training, you always wear a pulse strap. It gets the max pulse right and definitely gives better precision on the VO2Max estimate.

[@ann_intube]

That moustache. Wow. Not enough comments appreciate it's magnificence.

[@joalindkvist947]

I have watched houndreds of heartbeat videos, but yours are the best. Thanks!!! ❤️

[@DrAndrewSteele]

Thank you!

[@Whodatbuoy]

Love this format and the simplicity of your KZbin style. Don’t feel the need to join in the thumbnail mania though hahaha.

[@DrAndrewSteele]

How could I not celebrate that moustache (And thanks!)

[@therabbithat]

@@DrAndrewSteele i already watched the one hour video on Medlife crisis's channel and i only noticed the moustache now after reading this comment

[@DrAndrewSteele]

@@therabbithat He wears is so naturally

[@george6252]

BLOWS MY MIND ! People are astonished that Fitbit is overcounting steps ON THEIR WRIST. Wear it above your ankle held in by your sock.

[@kelgar1]

Really useful information, thank you

[@tootalldan5702]

Good video. My problem is the beta blocker (forcing a lower heart rate, after acute heart failure). So me getting to a higher zone on my Garmin isn't achievable. Resting is usually about 50 and a "fast" walk (which I can talk on the phone, for me) is 120 bpm. I have gotten up to 138 on swinging a bush ax and can maintain for an hour tree cutting/ moving wood as an exercise. HBP is my culprit with pill control and I eat healthier with extra salads per day. Vivosmart 4 was a gift from a friend and used since Christmas 2022. Thanks for presenting!

[@Respectable_Username]

Was looking at the numbers from my apple watch while watching this video, and it's interesting to correlate resting heart rate with what I was doing at the time

[@ian4iPad2]

The Dr. makes a good point regarding wearable device data. It’s better to view it as relative rather than absolute measures of fitness. So, if your watch tells you your fitness is improving over the weeks that’s probably good enough, but don’t think the actual number it’s giving you is absolutely right.

[@mongoosae]

I remember hearing that while the VO2 max estimate on watches wasn't necessarily accurate, as long as it was precise (ie same person same conditions gets same result) it was still a worthwhile metric to see how it changed for you over time. so you don't care about the absolute number, but your trend

[@BenjaminCronce]

There is value in a relative number. As long as better is better and worse is worse. And like mentioned in the video, seeing progress has a positive psychological effect.

[@vikram.SumerSingh]

Great video, everyone using a smart watch needs to see this

[@AddySwann]

Great video very interesting, I'd also say that the amount of time sleeping is another very important metric that the watches can measure. Like all the data wearables measure it's not always the most precise. I question its accuracy in measure the different zones of sleep and quantifying the quality with a sleep score but people often neglect sleep when its really important for maintaining and improving health and fitness.

[@mackieincsouthsea]

Brb writing a love letter to Rohins stache 😍 Very pleased this popped up, always good to have another insightful creator on my sub list! 👌

[@DrAndrewSteele]

Thanks, welcome on board! And send my regards to the face furniture

[@hiteshchand]

Very interesting and informative video 👌

[@Respectable_Username]

Almost all the times my watch has thought I'm exercising hard enough to report a VO2 max have been when I've been carrying heavy grocery bags home from the supermarket, making me seem a lot less fit than I am. Or at least, that's my story and I'm sticking to it!

[@DrAndrewSteele]

Haha!

[@Nonixification]

The problem with resting hr is that some people have naturally lower rhr therefor it doesnt mean they are fit. So it can be very misleading. Also the best for everyone to use a chest hr for running and get your zones dialled in. If you can run in zone2 faster in the future that means you are improving.

[@Mamilian]

Calculating an accurate VO2 Max using running data is inherently more difficult for the reasons you mentioned, but devices like the Garmin are getting better at it (as you note) as GPS accuracy and OHR sensors improve, but there have also improved with the introduction of algorithms to calculate running power. It's my understanding that VO2 Max estimates using cycling data are much more reliable because it requires a power meter. The device is not guessing based on pace, which can be influenced by a massive number of variables any more. It's using a metric that provides a much tighter number. Obviously, the calculation can only be as good as the data provided, a dual-sided (or total power) PM is going to have higher confidence than a one-sided. All that said, the value in almost all of the data that is captured, calculated, or estimated is in looking at the trends more than the actual number.

[@LeeRaymondCM]

One indicator that Fitbit has, within the sleep analysis, is the percentage of time your HR is below resting HR. I find that correlates quite well with how restful I feel about the night of sleep. Like other indicators, it's not so much about the actual number, but a trend over time. Eg , if I realized that this percentage has fallen to low numbers in the past week or 10 nights, I'll try a few things to make myself rest a bit better.

[@Sejdr]

Very interesting!

[@therabbithat]

I would say use the watch a week every month, learn from it, apply what you've learned, do the same the next month until you've got good habits going, then just use it every few months for maintenance. Don't use it all the time and let it become neurotic. Remember one part of why lower heart rate is associated with health is that it's associated with less stress, so don't cancel out a percentage of your gains by ruminating over numbers every day I also want to say that you can get these for about 15 euro, they are accessible for people who can't access expensive health fads

[@Mikeztarp]

I appreciate your attention to data and details, and I look forward to the rest of this wearables series. A fantastic resource for this is Andy Galpin. He gave great info during a recent guest episode of the Huberman Lab Podcast on how to assess your fitness: protocols, minimal and preferable numbers, etc.

[@DrAndrewSteele]

Thanks! More nerdy data and details to come :)

[@stargazerbird]

I’ve always had a low rhr. When I am on a calorie deficit and running it tanks to 50. Overeating instantly raises it. I actually use it a way to check whether I am in a deficit. I think in order to maintain a low RHR you have to be doing all the healthy things anyway. So it’s just a simple tracking thing.

[@RichJT87]

I hadn't seen the glorious moustache. Wonderful.

[@Hick25]

as a 25 year old smoker and non exerciser my resting heart rate was high 70s in June 2022, as of December 2022 my resting heart rate is high 50s. It’s strange because in that time period i haven’t changed a single thing, still smoking and not exercising, eating the same meals and weighing the same

[@ChrisUK70]

Thanks a really useful to know what a cardiologist thinks is worth paying attention to on these devices, I have a Garmin Epix Pro it tells when my sleep is bad. I don't need a watch to tell me I have bad sleep 😀 Also nice to see Rohin sporting the Black Adder General Melchett moustache!

[@LukaszWiklendt]

For the graph at around 3:00, I wonder if XKCD 2311 is applicable?

[@markpaul1958]

I am now 65. Fitbit has consistently been showing my VO2 Max between 45 and 51 for many years. I was quite flattered by this :) However even if it is 20% off target my current 48 would be 38.4 which is still in the ' very good ' category. I think my Fitbit gives accurate heart rated from resting to about 120BPM and then it is all over the place. Good to see videos like this which bring some perspective and hopefully some detachment from wearable devices.

[@jimf671]

As a young adult, above average fitness, more accidental than training, I was textbook 72bpm resting. Once I started winter climbing I really noticed things changing. Was 47/48-ish bpm sometimes in my late 30s and 40s. Now same age as rock n roll and had a rather inactive year for training and hill days but 49-53 bpm resting. Going straight out now for 6000 steps up and down that hill before bed. 😎

[@yengsabio5315]

My resting heart rate is equal to or below 60 bpm since I returned to mountainbiking in 2020. I'm 40 years old now.

[@yengsabio5315]

On days that I don't ride my bike, I walk at least 6,000 steps.

[@chrisogrady28]

My resting HR is 27bpm, and garmin's VO2 is maxxed out at '60+' I expect to live to 500

[@therabbithat]

Scientists say the first person to live to be 200 may already have been born. I believe i am that person.

[@aeriegrove]

Garmin had me at a VO2max of 57 for running, which I was pretty proud of as a 37 yo. Then I did a proper test on a treadmill, worried it that the results would be well below, but turned out it was almost 70! In that moment I realised something. I've always been a homebody nightowl guy who liked to party a bit much, now I'm up at dawn on the weekend training for a marathon PB, and I don't intend to ever stop

[@briandriscoll1480]

70 puts you into Olympic track territory, or at least very close. You didn't get that from partying.

[@aeriegrove]

@@briandriscoll1480 that's true, and I think I have full gassing it on my bike after every stop light to thank for a lot of it. Unbeknownst to me I was probably doing many vo2max type efforts every day for a decade before I started looking closer at these things

[@nickjunes]

@@aeriegrove Why did you ride a bike so much?

[@TheDrokon]

What are some of your running times/paces?

[@rujmah]

Great introduction to your channel. Really interesting stuff. And applicable. :D

[@DrAndrewSteele]

Welcome! And glad you enjoyed the video! :D

[@stargazerbird]

Heads up about the intensity minutes on your tracker. How many you get awarded is dependent on your max HR set on the watch. Check this is closest to what you see on a high intensity runs etc and do not rely on the age calculation which is very inaccurate, especially for the older age groups. Too low and you will get minutes for just washing the dishes, too high and a walk will not show up. Love my Garmin. It got me doing those steps which then progressed to running. My VO2Max climbed five points over four years. Is in the top 10% for my age group. Data is power. Sometimes the glitches annoy but the forums help to understand and fix issues.

[@ConceptualQuanta]

Have you looked at "running power" and the variants of that? Similar role to heart rate, but it's more responsive (in nominal cases), giving you a sense of when you're loading yourself before your heartrate responds to the load. I won't bias by mentioning any brands. I will call out there are several meanings to the term since you can measure power in different places and ways. Related to what you're looking at and possibly an interesting avenue to look at in parallel with it.

[@alicejwho]

I'm a 57yr old woman who likes to cycle. My heart rate rests in the low 40s when I'm just sitting there (on the sofa, not my bike!) (I feel great but nevertheless it freaks me out) and my max hr cycle up a really steep hill is 188bpm. I don't drink wine or eat late any more because it makes me wake in the night with a 130bpm hr. Very very scary.

[@Travlinmo]

I was told in a chiropractic new patient training to get 30 minutes/2 miles of deliberate walking time daily. I have followed that pretty deliberately for 20+years doing 2-4 miles most days. My resting HR remains about 60bpm. (I try to walk 2.5 miles a day minimum at 17.5 minutes per mile).

[@marcdaniels9079]

Chiropractic??? Medlife Crisis not a fan 😅

[@marty197666]

As a reasonably fit athlete (in my 40s far from elite) I do find this fascinating. I’ve always had a very low resting hr since I started training in my teens at less than 40 and a max of 187 with a functional threshold of 170. Nice to know I’m protected against a lot

[@patrickkalin4437]

How would you describe functional threshold?

[@marty197666]

@@patrickkalin4437 it’s from cycling, my functional threshold power is around 270 watts, I can hold that along with a heart rate of 170bpm for an hour.

[@aleperception3626]

Most doctors do not consider that athletes can have a resting heart rate even lower than 30 per minute. My heart rate now is 36, which is not even included in the graph shown at the beginning of the video. This is a problem when we are to be diagnosed for desies. A resting hart rate of 80 indicates more than twice our baseline but we may be regarded as healthy and missing the diagnosis of potentially dangerous infections!

[@yengsabio5315]

@@marty197666 I don't know my VO2max & functional threshold; I haven't measured it. But since I returned to mountainbiking, my resting heart rate is somewhere between 60 bmp & below.

[@caseyernstmusic5748]

Great video. I like all the data and explanations

[@DrAndrewSteele]

Thank you!

[@marcdaniels9079]

Max Heart Rate does not mean you are completely exhausted. It is something you cannot maintain for long but certainly you can endure multiple efforts at Max HR and continue to exercise for several hours. I know because I have done it. Of course as cyclists like to say you only have so many matches to burn so these repeated efforts will create fatigue but if you are well conditioned they do not leave you completely exhausted!

[@robertotomas]

I’m 1.92m tall, and there is no way I can complete 10000 steps in only an hour. My mom and I walk together a lot, for a time we used the same Fitbit model. She consistently gained 50% or more more steps than me. I’m curious if that consideration shows up in any of these studies.

[@DrAndrewSteele]

That’s a really good question! I’ve never seen a study that takes that into account (though step counting is definitely not my expertise!) and I suspect because most people are about the same height (‘most’ and ‘about’ are doing a lot of work there…) it probably comes out in the wash…unless you’re super-tall or -short!. Probably a good reason to go with my favourite stat, Active Zone Minutes. :)

[@briandriscoll1480]

Run for an hour and you can.

[@marcdaniels9079]

Of course you can! Try harder

[@dresden_slowjog]

Make smaller steps :-)

[@TheDrokon]

Ignore 10k steps. It's marketing by a Japanese fitness company. The only thing your heart cares about is time in zones.

[@cyc00000]

Regarding v02 max, how would a device go if it was calculating this with cycling power output? and the riders weight etc..

[@janknoblich4129]

Dr Francis has an insanely dope mustache

[@apriljohnson6191]

Oh, I am so grateful for this video, as it answers questions I had for a long time. Just one question - you said that the watches were an absolute measure for V02Max - don’t you mean a relative measure? If I’m going to use this as a relative measure, I need to make sure it’s a good relative metric. :-). It would stink if it said I was improving and I wasn’t. Again for this excellent presentation of this information (to both of you)!

[@DrAndrewSteele]

Yes, the watches give a fairly uncertain estimate of absolute VO2 max, but they’re probably pretty decent as a relative measure-ie, if you see yours improving, you’re probably doing something right! And thanks!

[@hikerJohn]

I use to have a resting HR of 80 . . . turns out I had renal cell carcinoma. Now it's 60-65. Lower heart rate does not lower your risk of cancer . . . some cancers literally raise your HR. It's not a RISK but a SYMPTOM.

[@old4004]

New subscriber. What walking speed qualifies as a "moderate pace" for the 150 minutes? Thank you from Texas.

[@DrAndrewSteele]

Thank you, and welcome! It’s difficult to give a precise answer, but as long as you’re not sauntering very slowly, most walking is probably OK. It certainly doesn’t need you to be breaking out in a sweat or anything. Well, maybe that doesn’t apply in the Texan summer… :)

[@Ballacks101]

This video was recommended to me by KZbin. I thought it was a joke to start with; two blokes on garden chairs with half an upside down skeleton and one ridiculous moustache. However, very interesting. Learnt a lot, thanks.

[@DrAndrewSteele]

Haha, the topsy-turvy world of KZbin, where two blokes on garden chairs are legit and yet those inhabiting flashy podcast studios are often, well… Thanks for clicking! :)

[@teddybear5788]

At 19 years, competing top-level in horse riding, my resting hr is around 60 and I‘ve come out of the competition ring with heart rates of 200-210, according to my apple watch 6. I really need to do some cardio I think 🫠 the problem with horse riding is that while it can be a decent cardio sport, you have to make it that way and the horse needs to be capable to do that too. But after 9 hours work and 3 hours at the barn when do I exercise?? 😩

[@amandaball7116]

Thanks for the video. What about HRV

[@DrAndrewSteele]

We did actually talk about that so there’s a video on he way!

[@togarchitecture]

On VO2 max accuracy. How do you think the accuracy of these measurements would be affected if taken during cycling with a power meter as you then have a pretty exact measurement of the work load you are doing?

[@spanky590]

I was about to ask the same

[@perfidy1103]

I usually wear a chest strap when it comes to measuring heart rate when exercising. Like Rohan, I don't pay attention to it during exercise (I either use feel for low intensity cardio, or pace/power targets for higher intensity intervals, or for sprints I just max out), but I do like collecting data almost pathologically. I'm not sure how accurate chest straps are however. I assume they are much more accurate than the optical sensors on watches, since they are detecting the electrical signals that cause the heart to beat, but I don't know if they are perfect. As a side note, the 220-age has always been funny to me. I am 38, and hit a 206 heart rate in a recent interval running session (measured with a chest strap). I like to imagine I have the heart of a 14 year old, but in reality I suspect I have a smaller than average heart compared to my size (1.99m/90kg) and it has simply adapted to beat faster to supply the same flow rate than a larger heart would manage with a lower heart rate. I've heart stories of professional rowers of the same age with max heart rates (and lactate threshold heart rates) varying by 40+ BPM too. It just seems highly personalised. Anyway, I came here from Medlife Crisis, and have smashed that like subscribe button!

[@DrAndrewSteele]

Welcome, thank for the sub! From what I’ve read, chest straps are essentially as accurate as medical-grade devices they’ve been tested against so pretty trustworthy. You might enjoy the previous video in this series, ‘Can you trust your smartwatch?’ :)

[@TesterAnimal1]

220 minus age is totally bogus. In my thirties I could barely attain 160. I was a cycling time triallist in my younger days with quite a few wins. It’s about volume delivered, not RPM.

[@briandriscoll1480]

Devices are all over the place as far as max HR. At 67, I can easily crank out 180 without max effort, on my Garmin Epix. On my Garmin Fenix 6 a couple years ago, I hit 190 while cycling. Are those numbers real? Well, 25 years ago in a lab VO2max test, my HR maxxed out at 186, at which point further intense effort became impossible, and I felt like crap afterward. I find it hard to believe I'm still there, 25 years later.

[@Mark0528]

@3:00 Where is the citation for this chart? I checked the description and could not find it. It would be great if when you presented data, a text pops up in the video stating "Source #4", and in the description you had citations in numerical order.

[@DrAndrewSteele]

Sorry, I put the wrong reference in the description! I just fixed it, or see pubmed.ncbi.nlm.nih.gov/28552551/ :) Good idea about numbering the references…I’ll think about including that in future!

[@ItsEverythingElse]

Epic stash!

[@sebastiand152]

Thanks, that's interesting. How would you see the heart rate variability as indicator for your health? Modern watches can measure it.

[@DrAndrewSteele]

Keep an eye out for a future video in which me and Rohin will cover this!

[@orbifold4387]

Zone 2 training isn't about heart rate, it is about lactate (below LT1, first lactate threshold). Going as hard as possible, while being able to hold a conversation, is the best way to determine it. Which is nice because anyone can do it, even without a heart rate monitor. Other nice thing about zone 2 is that it leads to improvements over time. Most people would start at 70% of their maximum HR, and then, after a few years, move up to 80-85% of maximum heart rate. Which is huge. Unfortunately, lots of people still train in zone 2 by heart rate, which means they will remain forever there without noticing any metabolic adaptations.

[@ashimpaudel612]

could you make a video about PAI? I really like your videos

[@shikharkgupta]

Loved this video. What wearable device do you use Andrew?

[@DrAndrewSteele]

Thanks! I recently switched from a Fitbit to a Garmin. Neither is perfect though… I’m having fun comparing them and might make a video about which one I’d choose at some point…

[@IPMan-me6lo]

In fairness, have to say, fitness devices on your wrist are just guides in my view. I wear Fitbit Sense, it is not perfect in all categories, specially the heard rate on the long run is questionable, but it gives me an overview of my progress, and it is one of the accurate sleep tracker.

[@sgordon8123]

Surely what really matters from your fitness tracker is it's reliability day to day. Comparing yourself to yourself on other days will hopefully be a valid exercise then?

[@mjcau]

Completely disregarded the impact of maximum moustache volume on health outcomes 😋 There must have been a reason all the old-school strongmen had exquisite moustaches😁

[@DrAndrewSteele]

If that’s a relevant factor, Rohin will live to 100…and I’ve only got a few years left!!

[@christopherbrand5360]

Regarding how long it takes to walk 10,000 steps, a brisk, purposeful walk for a normal person might be up to 120 steps per minute. An exceptionally vigorous, highly trained walker may be able to achieve 140 to 145 steps per minute. So this is ~84 minutes for a normal person walking fast to as little as 69 minutes for an exceptional athlete walking very hard. If you are running, then getting just over 10k steps an hour is normal.

[@alexstoyanov01]

I think that HRV is also a very important metric and can be measured by watch, or by smart phone

[@DrAndrewSteele]

Keep an eye out for an upcoming video with more of my chat with Rohin when we talked about that!

[@RidleyJones]

I don't think I've ever gotten an accurate measure of resting heart rate because I ALWAYS get nervous/performance anxiety when it's time to take it, even if just a little and even if I'm taking it myself in a calm environment. So I feel my pulse quicken. I've been resisting getting any kind of wearable but the fact that it's always on and I can't always be nervous about the measurement might mean I get an actually accurate measure.

[@DrAndrewSteele]

I get terrible white-coat hypertension and tachycardia (ie my blood pressure and pulse measurements in the doctor’s office are much worse than at home!) so I feel you!!

[@ThePetalesharo]

@@DrAndrewSteele Same here with the white coat syndrome! One thing I've found that helps it be a little more accurate at the doctor's office is to hold/rest your wrist across your chest just at heart level (it's how it's supposed to be taken especially with wrist monitors). Also if you can get there a little early and relax after driving. And you're dead on Ridley with wearing it all the time you can't always be nervous, IMO it's worth knowing and tracking

[@DrAndrewSteele]

@@ThePetalesharo Good tips! Alas, to add to the white coat hypertension, once a nurse took my blood pressure after forcing me to run down a corridor carrying my bike so relaxation wasn’t an option!!

[@Marty72]

The Polar H10 chest strap doesn’t use exercise to measure your VO2 max it get’s you to lay on the floor for a set time, and then stand up.

[@DrAndrewSteele]

Yes, I almost mentioned this but then decided to keep things simple because most devices do a measurement while you’re active! The H10 (and I think a few other devices) seem to use some combination of resting heart rate and heart rate variability, but from the papers I saw they tend to be (even) less accurate… I’ve been playing around with the one on my H10 and I’ve not quite worked out why but my measurements vary wildly!

[@Marty72]

@@DrAndrewSteele I don’t know how accurate it is, but I find it tends to match what Garmin predicts. The problem with most of the VO2 estimates is that they need the person to input their training volume on a 1-10 scale. Do you know if VO2 estimates using a power meter on a bike/trainer are more accurate? Garmin will give a separate VO2 estimate for running and cycling and they often don’t match for me.

[@DrAndrewSteele]

​@@Marty72 I wonder if this might be the issue…I reduced my training volume in the Polar app (after a few busy months) and my VO2 max dropped by 15! LOL. I’ve not seen any data for bikes/trainers specifically, but my guess is they’d suffer from most of the same problems of indirect measurement-they might be a bit better because they know exactly how hard you’re working because they set the resistance etc, but they still don’t know any specifics of your physiology…

[@IMBlakeley]

I'd really have trouble with hear rate. I can be walking hard and my tracker sometimes will be reading 120bpm which seems fair but sometimes it is 70 which seems unlikely. Swimming for an hour and it is recording 150+ a lot of the time and I am pretty sure that I am not working that hard, conversely I only see 150+ when dry if I am running.

[@playlist5455]

The optical wrist watch tracking can be very inaccurate. I've found it off be up to 40bpm either way (not tight enough, too loose, arm hair causing mis readings). A chest strap heart rate monitor has been so much better.

[@RaphaelChaleil]

For VO2 max, you can do a Cooper test, run 12 min as fast as you can on flat surface (ideally a 400 m running track). The distance covered is correlated to the VO2 max. One of the criticism is that 12 min is very long and it is difficult to sustain max effort for that duration, so it could possibly under-estimate the real value that would be measured in lab conditions.

[@DrAndrewSteele]

Interesting, I’d not heard of that before! That’s like a much simpler version of what the watches are doing…I wonder how it compares…

[@RaphaelChaleil]

@@DrAndrewSteele Cooper KH. A means of assessing maximal oxygen intake. Correlation between field and treadmill testing. JAMA. 1968 Jan 15;203(3):201-4. PMID: 5694044.

[@RaphaelChaleil]

@@DrAndrewSteele Penry JT, Wilcox AR, Yun J. Validity and reliability analysis of Cooper's 12-minute run and the multistage shuttle run in healthy adults. J Strength Cond Res. 2011 Mar;25(3):597-605. doi: 10.1519/JSC.0b013e3181cc2423. PMID: 20647946. According to this, it is a fairly reliable estimate of VO2 max but only in relatively fit subjects, so not applicable to untrained subject (I suppose running flat out for 12 min needs a relative amount of training to begin with) and doesn't work well on the other end of the spectrum (i.e. professional athletes)

[@DrAndrewSteele]

@@RaphaelChaleil Really interesting! And certainly sounds like it makes sense. For example, I’m not sure I’ve ever run as hard as I could for 12 minutes (30 seconds, yes, 5-10k I have a reasonable idea, but 12 minutes?!) so I’d guess I’d improve a bit with practice, knowing how to pace myself. And presumably there’s a discontinuity between running and walking… Interesting that a bleep test doesn’t look bad either! Alas I’m slightly outside the 18-35 range where it’s considered accurate now haha

[@RaphaelChaleil]

@@DrAndrewSteele I think this is one of the big flaws of this method, it is almost impossible to be at max for 12 minutes, and a great part of the progress is probably due to better pacing with practice rather than actual physiological improvement (certainly in my case). But I think the cooper formula (VOzmax = (d-504.9)/44.73 with d being the distance in 12 min to the closest 100 m), is based on correlation and implicitly takes that into account. It means that with a lot of practise, the results might get more accurate as there must be a point when improving the pacing is reaching a plateau and the measure becomes then a true measure of VO2 max.

[@SubtleForces]

I wonder if there are studies using watches and chest straps. This would seem to reduce the error for the hear rate and I wonder how much this improves estimates for either the resting hear rate and VO2 Max. I don't like the intensity minutes. I am at 394 this week so far and seem to get nearly half the recommended amount with every training session (Last seven days easy runs come at 99, 86, short cross-country ski sessions at 73, 79, tennis at 64, 72). A single long cross-country ski session (75 minutes in zone 3) is already 225 or more than 3/4 of the weekly recommended target which seems absurd.

[@DrAndrewSteele]

A chest strap would reduce one aspect of uncertainty , but I suspect not have much impact given all the others! And given that watches do an OK job at heart rate measurement generally (see my previous video) I don’t think it would help much. Would love to see some research on it though! And the Active Zone/Intensity Minutes top out at a multiplier of two, so your 75-minute skiing would be 150, not 225. And remember the recommendation isn’t for super-active people! No harm (and probably some benefit) in going quite significantly above it…

[@SubtleForces]

@@DrAndrewSteele Thanks for the comment. However, I can confirm that the garmin app for that XC=ski sessions says: 75 Moderate; 75 Vigorous (x2) and underneath shows 225 min total. It is indeed a bit confusing, but it seems to count as 225 = 3x75

[@DrAndrewSteele]

@@SubtleForces Doesn’t that mean you did 150 minutes of skiing and 75 were moderate and 75 (× 2 = 150) were vigorous? That’s what my Garmin seems to be doing but I could be wrong!

[@SubtleForces]

@@DrAndrewSteele Definitely not: I only ever did 37 or 75 minutes (two loops) on those tracks. I use other tracks and not the one right next to my place, when I have the time for longer sessions and I checked twice that the total session duration is 75 minutes. It seems to be cumulative. In fact, this is the only thing which also explains a recent session where the intensity time is (slightly) more than twice the actual time. I find the calculation rather confusing and intransparent and this is clearly the main reason why I am not using that metric.

[@DrAndrewSteele]

@@SubtleForces How bizarre! I guess this must be a difference between Garmin models, because my watch definitely doesn’t do this. :) But that is very annoying!

[@jackkennard4539]

Is there a way to messure how fast the heart changes from a high (while working out) back to one's resting heart rate?

[@DrAndrewSteele]

Yes, there’s a reading called recovery heart rate that does just this! Some interesting science around it but not quite the solid evidence base resting heart rate has just yet… :)

[@airspeedmph]

I'm very curious (this is in regard with the discussion you had with Dr Rohin about ageing biology), what do you think about Dr David A. Sinclair theories about ageing? He has a YT channel for details, but there is also an interesting video made by Veritasium (How to slow Aging) which rather condenses things in 20 min. Is there any merit in what he says, or he is just another "guru"?

[@MichaelGGarry]

Sinclair also has some.....not so great moments. A lot of what he talks about seems to be fine, but then he has something that...well just google his name and businesses. There are other researchers looking into similar, plus Doctors like Brad Stanfield (www.youtube.com/@DrBradStanfield) who try to keep on top of all the research and advise accordingly.

[@highlanderthegreat]

a lot of medical people. drs and rehab and nutritionist say aim for 10000 steps a day... but if you are older mid 60s or 70s or older & you cant walk that far or long, how far /long should you ride your bike indoor or outdoor bike how far or long should you row indoor or how far should you swim????

[@DrAndrewSteele]

I think the best metric is that 150 minutes of moderate or 75 minutes of vigorous activity per week, and spreading that out so you don’t do it in one massive binge is probably better too. :)

[@asphalthedgehog6580]

Funny () that my low heart rate gives me anxiety and fear attacks. A long way to go with that fear looking at these numbers.

[@damianm-nordhorn116]

12:22 would probably be more accurate with a chest belt sensor, right?

[@DrAndrewSteele]

That would reduce one aspect of uncertainty (ie the heart rate accuracy, obviously), but I suspect not have much impact given all the others! And given that watches do an OK job at heart rate measurement generally (see my previous video) I don’t think it would help much. Would love to see some research on it though!

[@Phoenix-ov5gg]

One explanation why a lower heart rate = lower risk of cancer is because people who exercise more are also more likely to eat healthy and take care of themselves

[@sebastiand152]

Besides of 5 year old watches, it would be great to know, how acurate modern ones in combination with quality breast straps do predict VO2max.

[@andreac5152]

Nice the low rhr protects from death despite the confounding factor of bradycardia. Guess that's a relevant issue only above a certain age.

[@lukasj7689]

i get these annoying notifications on apple watch during my sleep that heart rate drops below 40 on a short intervals (35-39 BPM range). Seems thats pretty normal...

[@satysin630]

I’m 38. 6’ and 100kg so board line obese and I smoke a couple cigarettes a day. But my resting heart rate is 56 which confuses me tbh. I know I need to lose weight and stop smoking. I’m just interested to know why I have a “good” resting heart rate without a very good lifestyle or even being all that fit??

[@stephentroake7155]

What about social connection; say, the number of people you can count on in an emergency,, for example? Didn't the Harvard Study find that the greatest predictor of wellbeing and longevity was some function of the strength of your (real world) social network?

[@locochingadero]

great video! I hated the part about resting heartrate, but that moustache made up for it by a factor of 100. I'd pretty much assumed that the masculinity requirements to manifest such a beast were lost to history.

[@darrenparis8314]

Why mechanistically does VO2 max matter?

[@mdaniel202]

What about heart rate variability?

[@drayner2517]

I’m left handed and received an Apple Watch for Christmas. It was showing that I was doing a lot of incidental steps. I wondered if it was picking up the movements I make with my left hand so I swapped it to my right and bingo - the incidental step count came down.

[@user-fl5lr1nm5v]

Heart rate variability (HRV) seems to be a more important metric to track, yet it isn’t mentioned. Strange.

[@alanmalarkey]

Yes, not sure what it means. Mine seems not to vary much

[@user-fl5lr1nm5v]

@@alanmalarkey HRV is a non specific marker of stress. It correlates inversely with the latter. A low HRV, assuming it has dropped from your baseline, means something is not quite right with your health and your body is struggling to fix this something. The issue could be lack of sleep, psychological stress, impending illness (like a flu starting up) or a chronic health problem or something else. The practical aspect is this. If the HRV has dropped, look for a cause but also be aware that it’s a sign to take it easy that day. This might mean having a light workout rather than a heavy one, more sleep etc..

[@BobBob-uv9fq]

Resting hr 44 ,,good for 55 tbf

[@javiTests]

2:50 My theory, from a non-medical person, is that the lower the heart rate the better the health. When I got COVID I noticed it because I went from my normal 50-55 bpm to 80 bpm resting (that was basically my only symptom), so when something is going wrong in the body and it needs to spend more energy for it, the heart rate increases. Also, it could be due to the metabolism. The lower the metabolism, the lower the heart rate, that I think it's my case since it started to go down when I started intermittent fasting (I started with 16/8 and now I'm more like 20/4, but if I have to cheat one or two days, I cheat 😂). When the metabolism lowers, the cells don't multiply as fast so the probability of cancer lowers and maybe the autophagy mechanism is triggered as well, so cancerous cells are killed sooner. Again, this is a theory from someone just curious about medicine and I could be wrong in many of the things I've said!

[@DrAndrewSteele]

I noticed this when I had covid too…with almost the same numbers! 70s and 80s bpm _while sleeping_ was pretty wild, and I had some crazy covid dreams…

[@maiqueashworth]

Is there a watch that gives vo2 Max?

[@DrAndrewSteele]

Yes, lots of them do actually! Some of them give it a strange name (eg Fitbit calls it ‘cardio fitness score’ for some reason), but it’s often there somewhere if you poke around in the app.

[@WaechterDerNacht]

Why can't I focus on the video and instead constantly wonder if it is a real moustache...?

[@extrastuff9463]

Ah yes the pointless VO2 max readings of my watch, my Garmin watch gave me better scores in the past while everything was objectively crap at that time. This was a month or so after the total hip replacement while still having anemia that the doctor considered worth doing something about. Somehow it gave me higher scores presumably because the left leg muscles were weak and more blood needed to be pumped around for the same amount of oxygen. Now the scores have gone down a lot, the anemia is mostly gone (still a bit below the lower limit) and I can walk long distances above 10 km with ease. I just get bored before that and sustaining a speed of 5.5 km/h is not a problem where I was limited to well below that as the muscles and general fitness still had to improve yet my VO2 max scores are lower. If it were up to my legs I could easily go faster too but there are other limiting factors elsewhere. So clearly walking isn't going to get anywhere close to a representative result and running isn't a thing I plan on doing. It's probably not the smartest thing to do with a prosthetic hip joint and my lower back won't tolerate all those impacts due to the damage from ankylosing spondylitis. On an elliptical or exercise bike at the gym however I'll happily do 250W for 15-20 minutes and 350-375W for short periods (60-90 seconds) are doable too. So I'm pretty sure the Garmin watch is underestimating things a bit. I do agree with Rohin though! It's best feature is watching what you do and provide data to remind me to do better, the reminders to go for a bit of a walk after sitting still too long is useful too. And the other function of a watch is useful too, I can check the time on it without all the distracting additional things to look at and interact with that smartphones have to offer. The only thing I object to is that the Garmin app likes to complain at me that I "moved less" on certain days purely based on steps while there were cycling activities recorded on that day in the 40-70 km total range. But I marked those "insights" as not useful and haven't seen them so far the last few weeks. Funny that the fitbit lets you record steps while in a cycling activity, if that's while at "full speed" it seems a bit silly. It'd be fine if it counts steps on moments when GPS measured speed drops to walking speed matching the number of steps detected, that'd be a clear indication you're probably not on the bicycle and doing some walking around or shopping without having stopped the activity. I can see why smartwatches struggle with getting the occasional few steps right however, noticed with my Garmin that it only seems to start counting after doing a certain amount of convincing steps and them jumps up quickly with roughly how many you did up to that point. If however I move a few steps, stand still for a bit and then move a few steps again the numbers are lower than actual. The various brands will probably have different thresholds for when to start counting and what kind of detected motions it interprets as a step since it's not all that hard to confuse folding laundry or using a broom as consistent motion and thus maybe counted towards step totals. I'm glad the anatomically correct skeleton was present in the video as well, it's always nice to look at.

[@andrecostainfante2172]

There is this channel called "The quantified scientist" he has great reviews and comparisons on watches

[@DrAndrewSteele]

Yes, great channel!

[@edwardjaycocks5497]

What kind of scientist are you and what credentials have you got to back it up or not back it up?