This post is by Phil Price, not Andrew.
Several months I noticed something interesting (to me!) about my heart rate, and I thought about blogging about it…but I didn’t feel like it would be interesting (to you!) so I’ve been hesitant. But then the NYT published something that is kinda related and I thought OK, what the hell, maybe it’s time for an update about this stuff. So here I am.
The story starts way back in 2010, when I wrote a blog article called “Exercise and Weight Loss: Shouldn’t Somebody See if there’s a Relationship?” In that article I pointed out that there had been many claims in the medical / physiology literature that claim that exercise doesn’t lead to weight loss in most people, but that those studies seemed to be overwhelmingly looking at low- and medium-intensity exercise, really not much (or at all) above warmup intensity. When I wrote that article I had just lost about twelve pounds in twelve weeks when I started doing high-intensity exercise again after a gap of years, and I was making the point that before claiming that exercise doesn’t lead to weight loss, maybe someone should test whether the claim is actually true, rather that assuming that just because low-intensity exercise doesn’t lead to weight loss, no other type of exercise would either.
Eight years later, four years ago, I wrote a follow-up post along the same lines. I had gained some weight when an injury stopped me from getting exercise. As I wrote at the time, “Already this experience would seem to contradict the suggestion that exercise doesn’t control weight: if I wasn’t gaining weight due to lack of exercise, why was I gaining it?” And then I resumed exercise, in particular exercise that had some maximum short-term efforts as I tried to get in shape for a bike trip in the Alps, and I quickly lost the weight again. Even though I wasn’t conducting a formal experiment, this is still an example of what one can learn through “self-experimentation,” which has a rich history in medical research.
Well, it’s not like I’ve kept up with research on this in the mean time, but I did just see a New York Times article called “Why Does a Hard Workout Make You Less Hungry” that summarizes a study published in Nature that implicates a newly-discovered “molecule — a mix of lactate and the amino acid phenylalanine — [that] was created apparently in response to the high levels of lactate released during exercise. The scientists named it lac-phe.” As described in the article, the evidence seems pretty convincing that high-intensity exercise helps mice lose weight or keep it off, although the evidence is a lot weaker for humans. That said, the humans they tested do generate the same molecule, and a lot more of it after high-intensity exercise than lower-intensity exercise. So maybe lac-phe does help suppress appetite in humans too.
As for the interesting-to-me (but not to you!) thing that I noticed about my heart rate, that’s only tangentially related but here’s the story anyway. For most of the past dozen years a friend and I have done bike trips in the Alps, Pyrenees, or Dolomites. Not wanting a climb up Mont Ventoux or Stelvio to turn into a death march due to under-training, I always train hard for a few months in the spring, before the trip. That training includes some high-intensity intervals, in which I go all-out for twenty or thirty seconds, repeatedly within a few minutes, and my heart rate gets to within a few beats per minute of my maximum. While I’m doing this training I lose the several pounds I gained during the winter. Unfortunately, as you may recall we have had a pandemic since early 2020. My friend and I did not do bike trips. With nothing to train for, I didn’t do my high-intensity intervals. I still did plenty of bike riding, but didn’t get my heart rate up to its maximum. I gained a few pounds, not a big deal. But a few months ago I decided to get back in shape, thinking I might try to do a big ride in the fall if not the summer. My first high-intensity interval, I couldn’t get to within 8 beats per minute of my usual standard, which had been nearly unchanged over the previous 12 years! Prior to 2020, I wouldn’t give myself credit for an interval if my heart rate hadn’t hit at least 180 bpm; now I maxed out at 172. My first thought: blame the equipment. Maybe my heart rate monitor isn’t working right, maybe a software update has changed it to average over a longer time interval, maybe something else is wrong. But trying two monitors, and checking against my self-timed pulse rate, I confirmed that it was working correctly, I really was maxing out at 172 instead of 180. Holy cow. I decided to discuss this with my doctor the next time I have a physical, but in the mean time I kept doing occasional maximum-intensity intervals…and my max heart rate started creeping up. A few days ago I hit 178, so it’s up about 6 bmp in the past four months. And I’ve lost those few extra pounds and now I’m pretty much back to my regular weight for my bike trips. The whole experience has (1) reinforced my already-strong belief that high-intensity exercise makes me lose weight if I’m carrying a few extra pounds, and (2) made me question the conventional wisdom that everyone’s max heart rate decreases with age: maybe if you keep exercising at or very near your maximum heart rate, your maximum heart rate doesn’t decrease, or at least not much? (Of course at some point your maximum heart rate goes to 0 bpm. Whaddyagonnado.)
So, to summarize: (1) Finally someone is taking seriously the possibility that high-intensity exercise might lead to weight loss, and even looking for a mechanism, and (2) when I stopped high-intensity exercise for a couple years, my maximum heart rate dropped…a lot.
Sorry those are not more closely related, but I was already thinking about item 2 when I encountered item 1, so they seem connected to me.
Wait—there was a pandemic since early 2020??? Talk about burying the lede.
See The One-Minute Workout by Martin Gibala which quotes some studies related to fat loss
> In that article I pointed out that there had been many claims in the medical / physiology literature that claim that exercise doesn’t lead to weight loss in most people
Only one of the links there works and what it says is that exercese _did_ result in weight loss in most people.
It’s kind of irritating that links at those professionally maintained websites are dead after a decade, whereas this blog’s links (for example) still work fine.
Ok, this is close enough, see point 3 in particular. https://www.vox.com/2016/4/28/11518804/weight-loss-exercise-myth-burn-calories
I’ve not followed the link to each study cited there but they are introduced with statements like “weight loss was less than expected”, “most people in these studies typically only lost a few pounds at best”, “physical activity alone led to only modest reductions” and “a lesser effect than you’d mathematically predict”.
It seems that they are in agreement with the surviving link from the initial set and exercise does lead to weight loss in most people. Not as much as expected ceteris paribus but that’s quite different from claiming that exercise doesn’t lead to weight loss in most people.
Yeah, good point, that surviving link says the mean weight loss was 3.3 kg, which is maybe not a lot if you’re obese but it’s definitely not nothing. And half the participants lost a lot less: the mean loss of the least-lossy half of the participants was about 1kg…which of course means the mean eight loss of the other half was more like 5kg. And of course some people must have lost a lot more than that!
Me, I’m rarely more than 3kg over my fighting weight so losing 3kg is a lot! (I’m motivated by performance, not weight, but on a bike these are pretty strongly related).
Anyway you’re right, what the study says (as opposed to reporting about the study) is that most obese people who exercise according to their program lost a few to several pounds, and also got in much better shape. I guess that’s not impressive if you’re expecting a lot more but it’s not nuthin’!
The flip side is, on my program a simple calculation suggests I’d experience nearly no weight gain just by adding a few minutes of high-intensity exercise per week to my usual routine, yet I lose a few kg.
I don’t understand why weight loss is the measured outcome in these discussions. My understanding is that it is (1) cardiovascular health and (2) the ratio of body fat that is more directly related to various health problems and quality of life in general.
Eg relatively low-repetition resistance exercise (3 set of max 20, takes about 10-12 minutes incl warmup) will improve cardiovascular heath, and build muscle mass, which increases the basal metabolic rate so it will burn up calories, which can result in fat loss… but at the same time insignificant weight loss for most people. They will just look leaner (muscle is dense). I look lean, yet I have a BMI over 27 — my doctor is now used to this, so she routinely ignores my BMI at annual checkups.
Body weight exercises can be done with relatively little equipment (a pullup bar, and odd items like a stack of books or a basketball), and can be learned from books or videos, so it is a low-cost medical intervention, taking about an 3×25 minutes a week, which most people can do at home with a bit of creativity. Yet I find that it is rarely recommended by medical practitioners.
Lots of people think others would find them more physically attractive if they lost weight, and lots of people want to be physically attractive to others. There is surely a large cultural component to what is seen as the most attractive weight, but I think the desire to be found attractive is perhaps innate. We are animals, after all, and have been subject to evolution just like all the others. I suspect this is why so many people care so much about weight.
You might be interested in https://www.researchgate.net/publication/317660005_Assessment_of_Metabolic_Flexibility_by_Means_of_Measuring_Blood_Lactate_Fat_and_Carbohydrate_Oxidation_Responses_to_Exercise_in_Professional_Endurance_Athletes_and_Less-Fit_Individuals
Hi Phil, at the ripe light of age of 35 I can confirm that my max HR has hardly if at all declined since my early 20s. I still do high intensity aerobic intervals (rarely above 95% at peak though) regularly as well. I do periodically neglect them for one reason or another and have definitely lost fitness but not seen much impact on max HR. But maybe being younger and the lay offs being not too long helps? Anyway, I have always felt as you do the max HR shouldn’t decline with age when regularly exercised. The main exception are the genetic freaks of nature who, in the course of training, develop very large stroke volume…the same people will often see resting HR go down into like the 30s…
The age-related fall in max HR is thought to be due to senescence of the conducting system of the heart. It doesn’t seem to be affected by fitness levels – for instance the standard formula max HR = 220-age still seems to apply to recreational marathon runners: https://www.frontiersin.org/articles/10.3389/fphys.2018.00226/full.
Chris, thanks for your comment.
My max heart rate in my early twenties was around 200 bpm. It was still over 190 at age 33 even though I was still pushing myself to my max fairly frequently over most of that period. So I didn’t have a player then, like you have had.
Then there was a long period, from about age 35 through about 44, when I never pushed myself to my maximum. By the time I started occasional maximal efforts again it was around 187. It was still about 182 at the start of the pandemic. That is consistent with a decline of about 0.5 bpm per year in my late forties through mid fifties, a bit slower than 0.7 bpm per year, which (according to the paper Nick posted) is the slope in Tanaka’s Formula, although my personal intercept term is much higher than the population-average one in that formula. But my experience over the past couple of years has been nothing like the gradual decline envisioned by that formula: I experienced a huge drop (when I took a break from maximal training) followed by a large increase (when I started again).
Nick,
Thanks very much for posting that link, it’s very relevant and interesting. Data!
Do recreational marathon runners train near their max heart rate? I’ve seen some recommended marathon training programs and it’s my impression— quite possibly wrong!— that they emphasize extended efforts that I would not expect to generate max hr. Although…hmm…some do promote fartleks, which I think are very taxing, so perhaps I am indeed wrong. I note that there’s some guy in his fifties with max hr over 190, I’d be interested in knowing whether his training is different from the others. If his max has been declining at 0.7 bpm for the past 35 years, and it’s still that high, he must have been off the charts in his early twenties!
Yep, my max has hovered ~ 200 bpm for the past decade+. I haven’t seen it above 195 in recent memory, but I have stopped short of the “truly 100% all out” effort over 5-7 minutes, say, required to elicit a max HR. I normally cap my high intensity workouts at 188-190 bpm on the intuition that keeping a little in reserve is wise and helps recovery at any rate.
My main ‘age related’ change to exercise is gauging my fitness based on clamped physiological intensities rather than what I can do with 100% all-out efforts. I have a rather large glycolytic capacity, but I’ve not seen any reason outside of competition (with self or others) to regularly plumb the depths of acidosis I can create. Healthwise, I’m happy to hang out on the border of Zone 4 and 5, and spend more time at low intensity aerobics and building/maintaining might and muscle with weights :)
Chris,
Perfect! Get your HR close to max a dozen times per year for the next ten years, then come back and let us know your max heart rate. Not kidding!
Haha will do!
I feel like my max has gradually drifted down over the years (I’m also a cyclist) but if I’m out of shape, it takes a few weeks to get back to my max during hard efforts. I’ve also alway felt that I can’t help but drop weight when I’m training hard – it’s just no problem (other than the problem of hard training being, you know – hard). I’ll give my favorite dieting quote, from LA: “you’ve got to be hungry”.
Same here, when I’m training hard — or even kinda hard! — I lose most of my ‘extra’ pounds, ending up somewhere in the range of 12-16% body fat I think. (I did once have my body fat measured in a “bod pod”, something like a dozen years ago, which at least gives me one calibration point).
In my case, this happens without me feeling hungry! If I do a relatively long, hard ride, I have to force myself to eat during it in order to avoid bonking; then I get home and for half an hour I have no interest in food at all; and then suddenly it’s like a switch is flipped and I’m ravenous. Pro cyclists in this situation will eat just a little and stay hungry, as in your favorite dieting quote, but they’re trying to get down to 6% or 8% body fat so they can climb faster. I want to climb faster too, but I don’t care nearly enough to be willing to be hungry all the time. I eat like a horse.
Art DeVany wrote a lot about high-intensity training, its benefits, and links to evolution in his book “The New Evolution Diet”. Here’s a brief free intro from 2000: https://evolutionarily.com/wp-content/uploads/2018/10/Arthur-De-Vany-Evolutionary-Fitness.pdf
In terms of personal experimentation, I too have noticed that high-intensity is far more impactful for weight loss than long stretches of low-intensity exercise. In both weightlifting and running, lifting heavy (close to 1 rep max – how close depends on what you’re training for) and sprints are very effective.
I’m always nervous these days about trying hard. Injuries are too annoying if you mess up! And there are so many ways to mess up it seems.
I think the emotion-exercise relationship is empirically pretty interesting. I feel like some days I am just barely making it on my jog and some days I’m flying. I assume there are lots of studies on this, but it seems simpler to just stick to the routine than worrying about optimizing anything.
Yeah, I can’t sprint all-out on the track anymore…or at least, the last time I tried I hurt myself. But I can still sprint on a bike!
Typo: “rather that assuming” should be: “rather than assuming”