Blood pressure and heart rate variability explained

For more on wearables, including two more videos with the amazing @MedlifeCrisis, go here: • Smartwatches series
You’ve probably heard that blood pressure is important-but what is a healthy blood pressure, how can you check yours, what can you do to improve it, can it be measured from a smartwatch, and…which is higher, a deadlifter’s blood pressure, or a giraffe’s?! (Yeah, I wasn’t expecting that either.) I sat down with Dr Rohin ‘Medlife Crisis’ Francis to chat all health- and heart-related numbers.
We also cover another common measure, heart rate variability, and what its potential use in fitness, illness, recovery and elite sport could be. I got lots of questions about HRV under our first video about the most important number for your health (watch here! • The most important num... ) so hopefully this video answers them!
This is episode five of my Smartwatches Series! In case you’re wondering about the connection… Samsung watches claim to be able to measure blood pressure from the wrist, while Fitbit, Garmin, Apple, WHOOP and more report sleep scores or recovery metrics based on HRV. Probably the best ‘wearable’ suggestion here is a blood pressure cuff-which also comes in far cheaper than a new fitness watch, unless you’re looking at one of the really low-cost offerings like a Mi Band!
Chapters
00:00 Introduction
00:44 What is blood pressure?
02:49 Maintaining a healthy blood pressure
03:50 Continuous blood pressure monitoring
04:50 Blood pressure while…deadlifting?!
08:38 What is heart rate variability?
10:49 HRV for tracking recovery
Sources and further reading
Suggestions for reducing blood pressure from the American College of Cardiology Clinical Practice Guidelines for high blood pressure (Whelton et al. 2017) www.ahajournals.org/doi/10.11... Definition of hypertension in Table 6. Non-pharmaceutical interventions in Table 15.
‘At ages 40-69 years, each difference of 20 mm Hg usual SBP (or, approximately equivalently, 10 mm Hg usual DBP) is associated with more than a twofold difference in the stroke death rate, and with twofold differences in the death rates from IHD and from other vascular causes. All of these proportional differences in vascular mortality are about half as extreme at ages 80-89 years as at ages 40-49 years, but the annual absolute differences in risk are greater in old age.’ www.thelancet.com/journals/la...
Credits
Heart animation adapted from en.wikipedia.org/wiki/File:CG...
And finally…
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Read my book, Ageless: The new science of getting older without getting old ageless.link/

[@DrAndrewSteele]

Watch the rest of my series on wearables (including two more videos with the excellent Dr @MedlifeCrisis!) here: kzbin.info/aero/PLg0VbZ0kyCHl0yKBAQZ0NaI-Gxax6_0oX&si=I6MD5Q8Xd17f3oiw Probably the most important thing in this video is the table of things you can do to improve your blood pressure at 02:54. It’s a simplified version of Table 15 in this paper (this link should take you straight to the table): www.ahajournals.org/doi/10.1161/HYP.0000000000000065#T15 If you’ve got any other numbers that your watch spits out that you want to know more about, let me know in the comments!

[@5kribbles]

Would you or Dr @MedlifeCrisis recommend those at home blood pressure cuffs?

[@DrAndrewSteele]

Yes, definitely recommended! They seem to be reasonably accurate (see eg bjgp.org/content/70/697/e548) and if you stick to well-known brands and ideally take it with you to the doctor to check with theirs if you get a measurement done (see www.health.harvard.edu/blog/home-blood-pressure-monitors-arent-accurate-201410297494 ), you should be good. And, as is the mantra for this series, trends will always be useful to know even if the absolute values aren’t perfect. Maybe I should do an accuracy comparison video… (Rohin could fit me with an arterial line?! LOL)

[@5kribbles]

@@DrAndrewSteele ...while deadlifting a VW Beetle!

[@DrAndrewSteele]

Hahaha

[@sebastiand152]

I can definetly see the times when I was ill in my HRV tracking. It appears to be semi quantitative, based on 9 month experience with a modern fitness watch.

[@danielkoschalka3955]

Exactly the same for me. Last two times I've been ill, my Garmin has shown my HRV dropping from a few days beforehand, and staying well below my normal level until the time I start to feel better again.

[@Kubose]

I have a Fitbit that tracks sleeping HRV (i know, questionable accuracy), and its interesting seeing the things that seem to impact HRV. Drinking, overexertion, and reduced sleep quality are the main ones, and when I had Covid last year it nuked my HRV for a while. Weirdly, when I take Benadryl to help me sleep my HRV actually goes up by quite a bit according to this thing, which i guess tracks with better sleep even though Benadryl gives me a sleep hangover. It is funny though, if I go back through my long term HRV stats, I can point out the binge drinking nights pretty easily lol.

[@atashgallagher5139]

The largest effect of benadryl aside from being an antihistamine is that it blocks acetylcholine. It's why it makes you sleepy for the most part. The interesting thing about acetylcholine is that although it makes you more alert and awake it also is a parasympathetic neurotransmitter, it lowers your heart rate and blood pressure, increases hrv, makes your intestines paristalsyis harder, your pupils constrict, your body just goes more into rest and digest mode. So, blocking it, although it would make you sleepy and less alert so you fall asleep faster, it will also make your sleep less restful. And interestingly enough acetylcholine also makes you release more growth hormone. Also regular usage of benadryl and other anticholinergics greatly increases your risk of dementia and early onset dementia.

[@AlanZucconi]

I'm still wondering what happened to that poor skeleton... 🤔

[@seamusmartin6010]

Looks like he died with his head up his a**

[@nohjrd]

I'm the assuming the poor guy was born with a pelvis for a head. Must have been teased terribly at school ;-)

[@mavrophor]

I believe it is an accurate depiction of the male skeleton. Clearly showing what anatomical part we use to form our thoughts with.

[@therabbithat]

His body was stolen from his family, probably

[@Dellvmnyam]

@@mavrophorthat part isn’t a part of a skeleton

[@cassieoz1702]

Got rid of my hypertension and BP meds by getting rid of sugar and most starches. Off meds within 10 days. Now 108/68

[@aethylwulfeiii6502]

The actual recommendations by experts like American Heart Association and Mayo Clinic is to reduce sodium chloride intake. And don’t give me that sea salt isn’t sodium chloride bullshite.

[@cassieoz1702]

@aethylwulfeiii6502 i have never even heard that particbullshite. The 'authorities' recommendations are not supported by modern research (were never supported by rigorous research) but the, somehow, can't bring themselves to admit it

[@KJSvitko]

It is just crazy that Doctors do not get nutrition training in Medical schools. Every doctor visit should include some nutrition discussion. The majority of the population is over weight or obese leading to high blood pressure, heart disease and cancer. Schools and hospital cafeterias should be leading the way to good health by setting the example of what is a healthy meal and teaching people what to eat and why.. Every person in the hospital for heart disease should have a nutrition class before being checked out from the hospital with follow up education and training in nutrition. Medicare and Medicaid should require patient nutrition education as part of their standard of care. Nutrition information should be run on the hospital TV channel.

[@sciencefliestothemoon2305]

The US is not Europe. The generalisation does not work so well. Improving the quality of the food the USA produces alone would help to tackle a lot of the obesity.

[@aethylwulfeiii6502]

MFer my FTP (one hour power) is 445 watts per 65.1 kgs with BMI of 20.1. Definitely not obese, but have high blood pressure anyways.

[@Fomites]

Important information - many thanks to both of you :-) Great heart action animation too - the best I've seen.

[@dannyred8668]

Thanks, very informative.

[@Symbiote-Man]

In October of 2022, I went to the hospital for chest pain. Turned out to be a nothing burger, but whilst I was there, they measured my BP, it came out to be at 240 at the highest. After some medication, it went down to 170. I ended up staying at the hospital for 3 days because of this, left the hospital against doctors wishes, went to my doctor and we talked. She put me on medication and told me to get healthier basically. I‘ve had my ups and down ever since, but I‘ve recently have been dealing with diverticulitis, which means I‘m not allowed to eat solid foods, drink carbonated beverages, no spices and all that stuff. My BP recently measured 102/76,my pulse used to be high as well, it’s been all in the 50s-70s, before it used to be in the 80s.

[@Ricky_B_2453]

Thanks again fo these videos providing insight into data that smart watches provide us👍 I was highly sceptical of HRV being anything other than a tech company buzzword, but it's reassuring to hear that it does serve a purpose. I've also found this series quite helpful in re emphasising how we should focus more on the trends in our smart watch data rather than the exact daily readings. Keep up the good work👊

[@DrAndrewSteele]

Thanks, glad you’re enjoying the series! :D

[@therabbithat]

Smart watches aren't good at accurately telling you your HRV, are they?

[@ryans1623]

I dont think so either the highest i ever scored was 50ms and got as low as 7 and i exercise 6 days a week low resting heart rate also.@@therabbithat

[@danielkoschalka3955]

Full marks for the magnificent tash!

[@perfidy1103]

I tend to use my Garmin's HRV reading as a sense check when I think I might be falling ill. If HRV is down in addition to me feeling it I'll take it easier for a day or two and see what happens. If it's not I will go ahead and train (though obviously if I start to feel bad I won't push as hard). It's early days (only had the HRV function for a few months), but so far it does seem to pick up illness. Agreed regarding bad sleep or drinking, though perhaps where HRV can be useful is motivating change. I am planning on giving up caffeine in February and I suspect if I see an increase in my HRV over the month I might be more motivated to *try* to keep it up beyond that month.

[@mariomenezes1153]

A lot of poorly detailed information here. That 120/80 number is a sort of random number. The heart is a pump and the circulatory system almost a closed loop. Anyone with the slightest understanding of physics will realize that it takes more pressure to pump a longer distance of pipes. Shorter the length of the pipes, less the pressure needed to get liquid out the other end. Each kilo of weight adds miles of additional blood vessels (pipes). It would be naive to think that a 4 foot 8 inch person weighing 130 pounds and a 6 foot eight person weighing 240 pounds would both read 120/80. And these people could both be athletes. Blood pressure is different for different people. It is more of a warning that a person may have matabolic disease that could impact cardiovascular risk than a problem in itself. The risks the doctor outlined are all correct, but they are more a function of high blood pressure caused by metabolic ill health than blood pressure itself. Any cardiologist will tell you that they have encountered people with high blood pressure who have lived to a ripe old age. These people were most likely metabolically sound and the high recorded number their normal setting. Also that 120/80 number that came out of the Framingham study was taken after the patient was made to lie down in a dark room for up to 15 minutes to relax before taking the reading. Certainly not the way you were doing it or that most doctors in a rush do it. Some food for thought 😊

[@ehjones]

When my lifestyle is sedentary my SBP is 140. If I do a reasonable amount of exercise (45-60 minutes of low intensity), my SBP is 120 for about 2-3 days afterwards.

[@DrAndrewSteele]

Exercise is the bestercise.

[@jackfaber7710]

@@DrAndrewSteele bestercise, haha, lov that

[@diverbob471]

Hi Andrew this video series is very informative, but there is one thing that i always think about, and that is with all this monitoring of blood pressure /HR etc, does this not stress some people out. Which could add to the rises in BP/HR and maybe not cause problems immediately but may very well increase problems down the line. On the other side i myself have increased BP as i am getting on now into my late 60!s i realised this not from testing my BP/HR often but by pulsatile tinnitus that seams to be constantly plaguing me.

[@DrAndrewSteele]

Yes, I worry about this too! (Ironically…) We did chat about this a bit and I do want to make a video about it, but I want to have a bit of a dog into the literature first-my experience has been a bit of both, in some contexts the numbers are motivating and in others they’re stressful and perhaps a vicious circle as you say! And thanks, glad you're enjoying the series :)

[@Ariegi854]

Yes it’s a common sense that would tell you that alcohol is bad for you, but I found out how eating to much is bad as well. The key word is „how bad it is” rather than „that it is bad”.

[@MathsForYouUK]

My age is 79 How come that whenever I think of going to the GP my blood pressure shoots up? and after the gym and I walk home my blood pressure decreases enormously? I have between 130 and 133 systolic; I have got it down to below 120 on occasions. while I have between 76 , (an outlier), and 85 diiastolic. I do the gym about two to three times a week. I need a day in between to recover. I hate the idea of taking drugs forever. I walk rather than run on the tread mill at between 5.5 and 5.7km/hr and do about 2.3 km in about 21/22 minutes. At about 1km my heart rate is about 110 to 115 ; my resting HRV varies between 69 and 85. At the end of 2.3 km "walk", my heart rate is between 133 and 125 depending on how stressed I am although I have got it down to 117 which I ignore as false. I sometimes row. Other exercises include abduction and adduction, torso exercises, deltoid and pectoral , deltoid exercises etc, I don't do weight lifting. For good measure I have enlarged prostate. I eat more fish than meat but TRY to avoid sardine and tuna to reduce the incidence of uric acid increse. I eat apples/pears/banana. for my breakfast I have muesli with 49% nuts, bran flakes and say pomegranite or strawberries Should I get worried? I hate going to the doctors' surgery. That has nothing to do with the doctors themselves, just me.

[@jzphoto]

HRV is very good way how to get to know yourself. You can tell people not to drink alcohol, not to drink coffee before bed, not to eat before bed, they all know. But if you start to measure HRV, you directly see the numbers how it really affects your quality of sleep and recovery, if you are trying to get better in any sports. I stopped to drink alcohol because of that. I do intermittent fasting, I have my last cup of coffee 9 hours before my bed time. I thought I need 8 hours of sleep to have "good" sleep, but this is not true. It really depends on many factors, and HRV is one of them. I can now have perfect sleep with scores of 85 or more only after 6 and half hours of sleep, when my HRV is balanced, my heart rate drops to 44. That is good quality sleep :) so I recommend to track HRV, it can really help you to understand your own body more.

[@carneirolucas6385]

Amazing video

[@christopherbrand5360]

At 11:12, I think Rohin meant to say bro-cus pocus. And the increase in heart rate with full lungs versus the decrease with empty lungs is the primary source of HRV as a function of “vagal tone.” There’s a bigger difference between these two states when we are relaxed and healthy than when we are excited or stressed.

[@DrAndrewSteele]

Haha yes! I cut a couple of bro science references in the edit but glad to see they shone through regardless! I did wonder how much breathing contributed, and definitely need to read some more about it-it must make a big difference which measure and what time window you measure over, presumably, and I’ve seen some papers that try to use FFT and other techniques to remove the breathing component of the variability…

[@Fehr270]

I’m waiting to see how long until my garmin watch is replaced with a patch attached over your heart for more accurate numbers or even an implant. As they become more common they will also be great data for research.

[@DrAndrewSteele]

Definitely an interesting time to be alive and a health data nerd huh!

[@therabbithat]

So much noise. I think anyone with high sensory sensitivity can vouch for too much information making it very hard to notice meaningful patterns. Heme review had a good interview with another doctor about this but I can't remember which it was

[@deus_ex_machina_]

@@therabbithat You're referring to the episode titled _The More Data You Have, the Further You Are From the Truth - Big Data Problem in Medicine_ ft. Dr Pavlos Msaouel

[@aethylwulfeiii6502]

That sounds heavy and heavy = slow.

[@cosmicaug]

At 7:09: «So, you know, I wouldn't advise Eddie-Hall-deadlifting-a-car kind of level. But weight training is good, you just don't have to go crazy! So yes, the body can handle short-term... spikes like that. I think at that extent you can do a lot of damage.» Is this statement "common sense" or reasonable inference based on the alleged mechanism of damage? I what I am asking is whether this is an empirically confirmed statement or more speculative (though not necessarily speculative in an unreasonable way)? It seems like it wouldn't be unreasonable to expect some sort of hormetic response when it comes to blood pressure spikes such that they could actually be good for arterial health despite how chronically elevated blood pressure is clearly harmful (just like also in other realms of physiology, different patterns of stimuli can have even opposing effects: such as how the long term physiological effects from chronically elevated cortisol are not the same as the effects of even high cortisol spikes). Any kind of reasonably intense exercise several times a week is good for arterial health so it is not unreasonable to suppose that a response to spikes in blood pressure might be a positive contributor to this effect (it is also possible that the benefits to exercise come strictly through other mechanisms and despite the repeated insult of blood pressure spikes rather than because of them -but I see no reason to suppose that, in at least some contexts, arteries are not going to respond with specific adaptation to imposed demand just like other body systems do). Do good quality studies addressing very high blood pressure spikes in a context of otherwise normal blood pressure actually exist? It seems like the at the upper level for this it would be incredibly difficult to recruit participants since people training at a more elite level are likely to include a number of confounders (including the use of ergogenic aids such as anabolic agents). So the question is how do we know where to draw the line? Are heavy deadlifts (with 1 repetition maximum attempts maybe weeks or months apart as many powerlifters might train) necessarily harmful? Certainly, you want to keep it below the level where you might blow out an aorta, Jón Páll Sigmarsson style. Unfortunately, most of us who might be susceptible to this probably don't know it until after the fact (with the exception of the few diagnosed with such conditions as Marfan syndrome & other connective tissue diseases). In any case, while no one should be expecting that training at an elite athlete level (or close to it) is good for health, where is the line drawn?

[@jmodified]

If blood starts to run from your nose, ears, and eyes, you pass out twice, and lose your vision temporarily (which is what happened to Eddie on the WR lift), it can't be good.

[@drakezen]

What are your thoughts on Kardia?

[@DrAndrewSteele]

Slightly unusual take but Rohin once used one in an in-flight emergency! kzbin.info/www/bejne/e5fWl6aQe9ecb9U In general…I think they could be a useful thing in the context of remote medical care/Rohin’s edge-case (!) above because a two-lead ECG could be enough to work out if further tests are needed. As an at-home device for patients…that would depend on how accurate the algorithm is, which I don’t know. If you’re older/at risk of AF for any reason, the pre-test probability of AF is higher so it’s probably more useful, but if you’re younger/otherwise have a healthy heart, the risk of false positives skyrockets regardless of how good their algorithm is!

[@DSAK55]

how does mental stress cause changes in blood pressure?

[@Cannonballdrive]

Yes, it does. Anxiety can rise blood preassure a lot! Then I have axiety, my BP can spike up to 160/100. When I’m calm, I have 115-120/70-82. There was study with combat veterans who had for years high blood pressure and anti high BP medications weren’t helping them. So they tried meditation. And in 3 months, if I remeber correctly, they had normal BP.

[@patricksmith4424]

Of course as exercise raises BP then more worryingly the prep for exercise also will, ie stress. There is a very fickle automatic connection between the brain and heart, which basically means that if there is even a hint of danger then, the heart will need to start working to get away from the danger. The problem of course is that in humans they are probably sedantry when the stress input occurs so the useful temporary blood pressure is just building up, not good. This is esspecially a problem when people have anxiety when having their blood pressure taken. The heart receives a danger message and does the opposite to what you want it to do.

[@pogoking4000]

I am super nervous when measuring blood pressure and my blood pressure and heart rate always shoot up 🤡 So I have to discard the first reading or two, sit down for a minute and then take another two readings when I calm down.

[@Callofdootie]

I can always tell when I am getting Ill or have recovered. My Garmin watch HRV goes into the amber / red.

[@DrAndrewSteele]

It’s definitely interesting that it seems to follow things like this, right? I’m watching eagerly for more studies to see if there’s anything in it!

[@ameliablack8688]

Thanks for the video! Do we have a source for the maximal systolic of 435 during a deadlift figure?

[@DrAndrewSteele]

I had a look around and the highest I found was actually 480/350 mmHg during a double leg-press!! pubmed.ncbi.nlm.nih.gov/3980383/ There are quite a few papers though so let me know if you find one closer to Dr Crisis’s number :)

[@milanpintar]

blood pressure and inflammation I can understand can cause problems in arteries but how does cholesterol?

[@jackfaber7710]

it's sits on arteries where it found inflammation and closes them. closed arteries = death. what else do you need to understand?

[@slowmigo]

My boy Pelvis Presley 💀

[@DrAndrewSteele]

He’s so hip

[@wazzup105]

Considering how bad most fitness trackers track heartrate I am weary of them doing HRV.

[@DrAndrewSteele]

The good thing is that most of them measure HRV overnight when their HR readings are most accurate… But HRV will definitely be harder, and I’ve not actually done a comparison and maybe I should!

[@guillaumepoirier3618]

Ce squelette avec le bassin à la place du crâne illustre-t-il l'expression avoir la tête dans le c*l ?

[@DrAndrewSteele]

Le LOL :)

[@TesterAnimal1]

@@DrAndrewSteeleI believe les enfants use “mdr”

[@tsmwebb]

White coat syndrome begs the question of which number most correctly indexes with the studied population data. If someone gets a single sample at the Dr's office of say140/90 but has a large n of samples taken at home that averages say 110/70 how does that person relate their numbers to the long term studies? If the sample data was gathered by white coated folk it seems like the Dr's number would the one be associated with harms by study methodology. However, the Dr's officie sample is a statistical outlier for the individual.

[@devluz]

They send you home with the device to measure your own blood pressure regularly. A one time measurement like that at the doctors office isn't very useful and they know that

[@tsmwebb]

Okay, but the question I had is how to relate those better measurements with the office reading when "much of the available BP-related risk information and antihypertensive treatment trial experience have been generated by using “traditional” office methods of BP measurement" (Whelton, op cit 4.1)

[@DrAndrewSteele]

Good question! I have seen papers suggesting that us poor souls with WCHT actually _do_ have raised risk factors (perhaps because we’re easily stressed in general?), but I think more research is probably needed. My guess would be that if anything the effect sizes in the classic studies might be slightly diluted by a few false positive ‘high blood-pressure’ patients. There’s also a far more boring practical side to this in that some of my high readings at the GP etc can be attributed to hilarious circumstances-like measuring my blood pressure just after calling my name and dashing off so fast that I had to run down a corridor with a 12 kg folding bike. LOL. That’s probably extreme but how many GPs have time to let their patient sit in silence for five minutes before doing a reading etc…

[@jackfaber7710]

@@tsmwebb if you see a dood at medical office and hes bp is 160/100, believe me, it's not a white coat and 100% he have a problem bp.

[@tsmwebb]

@@jackfaber7710 I'm pretty sure context matters. BP will vary with heart rate and, I suspect, how tense or loose the patient is. My working theory: the heart pumps a volume of blood with each beat, resistance creates pressure, elasticity provides a reservoir of pressure, and the blood has some momentum that resists changes in flow rate. It's a system with some complex resonance but roughly speaking an increases in HR or in resistance should increase both sys and dia pressure. An athlete who maintains 120/80 at 55 bpm in a relaxed state might hit 160/100 at 80 bpm while tense. Sitting for 5 min in a busy office might not bring the numbers into the typical range for that person. Both white coat syndrome and white coat effect have been observed.

[@tchevrier]

taking your blood pressure is quite painful?????? Since when? For whom???

[@tony-winyard]

I'm surprised that the choice for discussing HRV was someone who appears to have a more general understanding of the subject, rather than a deep expertise. While the individual's credentials as a doctor are impressive, expertise in one area doesn't necessarily translate to all health-related topics. It's important to acknowledge the extensive research that exists on HRV, which seems to have been overlooked in this discussion.

[@tootalldan5702]

Two variables to mention is salt and sugar. Either bind to water and in the blood, the volume increases and thus the pressure increase due to the volume. That's why some, have issues. Once control is taking the variables, you may find your BP is lower. In my case, I'm salt sensitive and diet has helped. I enjoy your talks, have a great day.

[@xntumrfo9ivrnwf]

Is that a real mustache...?

[@sreekumar7705]

Increasing fruit and cutting salt are not suggest. Please read up. Fructose can be damaging.

[@Arid379]

Lay in bed to take you BP. True way to take your pain

[@MikeHunt-rw4gf]

Algorithm.

[@zoltangaal1842]

Eating more veggies and less salt is probably the wrong place to start. Cutting out sugar, carbs, seed oils and anything that has plant poisons in it, well, that's the right place to start. Don't give misleading pieces of advice.

[@Alecmcq]

Not sure this doctor had the first clue about HRV.