What's your fitness age?

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Not sure what you are referring to here but I think it is pretty well established that exercise alone usually does not cause weight loss. The body compensates for increased calories burned by a combination of increasing hunger and decreasing metabolism.

I say usually because one can find studies indicating significant weight loss from only exercise. But these are a minority. A reading of reviews on the topic lead to conclusions like this:

A systematic review of studies with a minimum of 1-year follow-up (4) suggested that subjects who used exercise alone for weight reduction experienced minimal weight loss. Role of Physical Activity for Weight Loss and Weight Maintenance - PMC

I am not entirely sure what you mean by this. I will stand by my statement though that running without monitoring diet will not result in sustained weight loss. I’ve never lost weight while training for a marathon unless I also controlled diet.

Running increases hunger. One always needs to be careful about overeating when hungry.

Endurance training and yoga have both been shown to reduce resting metabolism as monitored by resting heart rate. Significant reduction in resting heart rate…

…occurs after only a few months—on average, three months with three training sessions per week. Effects of Exercise on the Resting Heart Rate: A Systematic Review and Meta-Analysis of Interventional Studies - PMC

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Look at this considering most of us live in a society that kills and destroys the human bionome. We can guess this does not always work. But we should not generalize it does not work.

Releasing appetite-regulating hormones: Probiotics may help release the appetite-reducing hormones glucagon-like peptide-1 (GLP-1) and peptide YY (PYY) . Increased levels of these hormones may help you burn calories and fat ( 19 , 20 ).
Probiotics and Weight Loss: How Probiotics Can Help You Lose Belly Fat.

Why bring it up? We are talking about abnormal hunger problems. People worked vigorously for millennial without gaining weight.

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Congratulations on losing all that weight! One word of caution though. Losing weight through muscle loss is not healthy, particularly for older people who naturally tend to lose muscle mass. The only way I know of to consistently maintain muscle mass is through exercise, with weight training becoming increasingly beneficial with age.

The effect is called sarcopenia and it begins as early as 30 but accelerates after 60.

Older adults need to be careful about how they are pursuing weight loss. I am not a doctor so take this with a huge grain of salt, but I would strongly recommend that anyone over 60 trying to lose weight should do so in combination with some type of weight training, preferably supervised to avoid injury.

This one study looked at patients with artherosclerosis. They found that while weight loss reduced cardiovascular risk, it was associated with a significant loss of lean muscle mass.

https://www.ahajournals.org/doi/10.1161/JAHA.119.013200

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And I don’t believe anyone has suggested otherwise…certainly not I. I think you’re making the mistake of not distinguishing NEAT (the point of my comments re: Jim Levine’s work) from volitional exercise in the context of interdependent variables and weight management.

In fact, your very own link suggests exactly the same…that failure in volitional exercise to produce expected weight loss outside the lab environment is mostly due to compensatory changes such as increase in appetite and consequent eating (increase in Cals In) and reduction in spontaneous movement/NEAT (decrease in Cals Out) Not so much “decreased metabolism”/BMR. Unless there’s an accompanying loss of weight (a bigger body expends more energy even at rest than when smaller…body fat is also a metabolically active organ). And if there is substantial weight loss accompanying this exercise…it’s worked, surely?

Now as to the notion of lower resting HR with endurance training…and yoga…I think you’re way off the mark in attributing this to reduced metabolism/BMR. Your link doesn’t suggest it, either.

There are indeed multiple factors at play…but not reduced BMR. You’ll find plenty of reproducible evidence showing this lower RHR very quickly with the adoption of a rational training programme and the biggies that’re usually cited here are increased blood volume and changes in the autonomic nervous system. This results in any energy demands being met by a greater stroke volume…i.e. every heart beat pumps out more blood so fewer heart beats are needed to achieve any given cardiac output. Add to that the more long term adaptations such as greater oxygenation of the blood at the cardio-respiratory interface plus greater capillary development in the muscles and increased oxygen extraction.

I got my first heads-up on this way back in the 1960s. I’d be about 15 at the time…knew nothing much about exercise physiology but was quite serious about my running and sport in general. At the time my dad was quite keen on first aid and every week…on a Tuesday night, IIRC…he’d go to local St. John Ambulance Brigade meetings. One particular night he came home and was quite keen to measure my pulse. Apparently, one of the local GPs…who was also our family doctor…was a guest speaker demonstrating correct way to measure radial pulse. When dad had a go , he was amazed to find our doctor’s pulse was no more than about 40 bpm. Lecture turned to this idea of runner’s heart and how it can confuse the unwary. Turned out that our doctor was an avid runner. His name…Bannister. No, not Roger (he was an eminent neurologist) but his cousin Fred. Yes, my pulse was also low…due to sport. Still is. To further emphasize the point that it’s minimally related to BMR, if at all, my current RHR is averging low 50s over the past week per my Garmin…my normal. Were I to take a trip to sea level and greater oxygen availability, it would likely drop to mid 40s (as it usually does)…just a few miles west of here and another 1000ft or so higher elevation and less available oxygen with each breath,it’d be romping away in the mid-high 50s (as it normally does)

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I did a diet once. Not from necessity per se but part of an educational exercise, I guess you could call it.

It all began in the Fall of about 2010 and, on one of the group ex/personal training boards I posted on, we had a series of posts discussing the various ways we helped our class members/clients to stay on the weight management wagon over the upcoming holiday season. Lots of individual tips that were useful.

Now, as it happened, there were 3 or 4 of the members who, in their day jobs, were registered dieticians and one of them made a comment regarding diets and dieting. It turns out that for her and the others, part of their courses required them each semester to follow a * diet * for 3 or so weeks…whether they needed to lose weight or not and for the purpose of instilling exactly what their future patients might experience/endure as a result of their recommendations. For all of them it was a less than pleasant experience so, they suggested that those of us who didn’t diet/didn’t need to diet to give it a shot before we got too bumptious in our recommendations. So, just like with my VO2MAX testing, I took on the challenge…just so I knew what I was talking about if I chose to talk.

I decided to go hog wild with the self testing and in the run up to Christmas bought a basic pedometer and clipped it to my underps every day same time (about 11 am, after my gym sessions and shower etc) Surprised myself by logging something between 12-14k steps until bedtime…mostly steps I couldn’t account for with dog walking etc.

Chose a diet from Oxygen magazine. A “cutting” diet for bodybuilding/figure competitors designed to preserve muscle. Came in at around 1600 Cals with around 120 gms protein a day, “healthy” fats, non starchy veggies. Totally nutritious and so totally similar to my regular eating habits that I thought “piece of cake”…or should I say, “bunch of celery, bag of broccoli and cauliflower and a carrot or two”?

Nice enough variety in the meal plan such that dh didn’t notice a thing (a few spuds etc for him) and I didn’t think too aggressive a calorie deficit for me. What a miserable experience though. Even though I was never hungry…protein and fat content ensured satiety…I found I started thinking about food/trying not to think about food in a way I wasn’t used to. More importantly, my steps dropped to about 7-8000. Not a couch potato by any means but enough to stymie a weight loss in someone who wasn’t aware. I had to give up after 10 days…didn’t need to start a dysfunctional relationship with food TYVM and, for all that suffering, I only lost about 1.5 lbs. Actually that’s not bad going for someone who’s very lean anyway…but also very close to losing nothing or even gaining if the constant thoughts of food had me snacking even just a little bit.

My post surgery step count of 500 or so a day is probably compensated for by the big drop in appetite caused by nausea thanks to my pain meds…but complicated by being so corked up. Just as well I can’t stand yet to get on the scale

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One of the reasons anyone marginally young should be sure not to wait until their 60s to start a strength training program…along with balance and proprioception specific stuff too. When it comes to maintaining muscle mass…especially those all important fast twitch fibers…it’s definitely a “use it or lose it” situation if exercise isn’t consistent and continuous. Gawd knows how it might be if there isn’t much available to lose in the first place.

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Why make the distinction? My premise is that increases in physical activity tends to increase appetite. Doesn’t matter whether it is “volitional exercise” or NEAT. How are the calories burned standing at a desk (NEAT) different from the calories burned jogging (exercise)?

Heart activity is a major contributor to metabolism. If resting heart rate (RHR) declines while all else remains equal, then resting metabolism also declines.

Your heart is working harder at rest in low oxygen than at high oxygen. That means it is using up more calories and increasing metabolism. From (coincidentally) Banister Nutrition:

In the mountains, our very remarkable bodies can make several adaptations over weeks or months to make the most of the limited available oxygen. Your breathing rate speeds up to compensate, working the diaphragm muscles harder. Your body makes more red blood cells to carry oxygen, and those blood cells become more efficient at delivering the oxygen to your tissues. Simultaneously, your cells’ mitochondria (energy-producing furnaces) multiply to take in as much oxygen as possible. Changes your body goes through to adapt to the higher altitude can lead to a slight increase in basal metabolic rate (BMR), the amount of energy needed to keep your body running smoothly. With time the BMR lowers but does not return to baseline, so metabolism overall remains ‘slightly’ elevated at higher altitudes. Does Altitude Increase Calorie Burn? - Banister Nutrition, LLC | OKC Dietitian | Nutrition Specialists.

So your example attempting to show the opposite actually demonstrates the relationship between heart rate and metabolism…a small change in heart rate correlates with a small change in metabolism. The degree of this relationship varies enormously between individuals, but within an individual a change in RHR typically means a change in resting metabolism.

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And right on cue, along comes Peter Attia…

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It is entirely possible, even probable, that the human body reacts differently to 100 calories burned over 10 minutes versus 100 calories burned over an hour.

And it’s also very likely similar on the intake side. It’s entirely possible, even probable, that the human body reacts differently to 100 calories ingested in 15 seconds (let’s say 8 oz of soda pop) versus 100 calories ingested over 15 minutes (let’s say a medium sized salad with a little dressing on it).

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Well, the reason for making the distinction in the context of this tangential discussion, is that a good many folk (yourself included, apparently) tend not to be aware of the extent that volitional exercise and/or caloric restriction can have an impact on this source of energy expenditure. Without this understanding…or realisation that NEAT even exists…individuals who’re aiming for a modest energy deficit by either dieting with a strict eye to energy intake or exercise, oftentimes end up with the disappointment of slow or no weight loss. Q 1

Now, I’m not talking about folk who’re shoveling food away like it’s going out of style or unable to resist hunger pangs but rather folk are actually controlling what they eat pretty well and putting in a reasonable effort at exercise (doing “everything right”) but, for whom that theoretical deficit provokes less unconscious, non volitional, exercise…NEAT. Expending, say 500 extra Calories in the hour spent at the gym, doing a pretty good job of not increasing energy intake to compensate…but “economising” on organic movement for the remainder of the waking hours. Likewise a dietary induced deficit with volitional exercise well controlled (per my own example)

Sorry, “heart activity”…as in heart rate…isn’t the contributor to BMR you’re trying to portray. Again your own link and emphasized by your bold type uses the word “slight” in the context of chronic altitude training (a fair bit longer than a long weekend/short va-cay) and even goes to the trouble of pointing out that, in comparison with the ability to perform a higher workload, increased muscle mass, it’s a minimal contribution.

FWIW, you’re not alone in this misunderstanding. I had the devil of a time trying to get class members/PT clients used to the idea that the calorie burn feature on their wearable was very inaccurate…and one reason their efforts at weight management were being thwarted. When heart rate is used in the algorithm that calculates energy expenditure, it actually discriminates against increasing fitness. So, for a fresh off the recliner athlete-in-training, they’ll find a sky high heart rate response for a very modest work effort (say a modest walk of 3.5 mph) and a corresponding appearance of a serious calorie burn. That same person after, say, 6 months of a structured training program might very well find a lower heart rate response whilst scampering along at an 8 min/ml (approx 8 mph) in addition to a lower RHR. Manifestly, running for the same time at more than double the speed, and the “tuned up” body that allows to such performance isn’t going to be demonstrating a lower metabolism however it’s measured.

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I have a difficult time understanding your posts but based on this passage we are in agreement on this point…significant and sustainable weight loss does not typically occur without monitoring diet regardless of exercise or NEAT.

So you claim, though at rest the heart is probably the most active muscle.

That’s because there is a lot of variation between individuals. But as a general rule, physical activity increases heart rate and energy expenditure. That’s why MD Anderson considers heart rate monitoring as one of the more accurate ways to measure calorie burn outside of a lab.

A heart rate monitor is one of the best ways to measure your calorie burn. How to determine calorie burn? | MD Anderson Cancer Center.

A body that is less fit works less efficiently than one that is more fit. Efficiency is about energy use. This means that someone who is out of shape expends more energy to do the same task than someone who is in shape. The change in heart rate reflects that difference in metabolic efficiency. Heart rate is a pretty good indicator of metabolic activity within an individual.

You appear to believe in the measuring power of VO2 Max. That’s all about oxygen. The movement of oxygen is all about the heart.

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Odd that MD Anderson’s spokesperson should accept the accuracy of the calorie burn feature on an HRM…most other sources do not. For but one…

As for VO2MAX measurement, it’s hardly “all about the heart” The calorimetry used to provide this figure is the same equipment that measures BMR, Resting Heart and oxygen utilisation (an accurate measurement of energy expenditure) during exercise. I wouldn’t call it so much a belief as accepting the weight of evidence.

Indirect Calorimetry in Clinical Practice - PMC.

This article is primarily geared to situations where accuracy is important (sickness) but the principles outlined apply to anyone interested in accuracy.

Dumping one more link for my own benefit rather than a Gish Gallop …to save me having to look for it again.

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That’s useful information. But what would be far more useful is if they can tell us whether all 7 devices measured high, or all measured low, or a mix. Because for the first 2 cases, we could at least make our own mental adjustments while using them.

I also wonder if the newer devices, now 6-7 years later might be better. After all, the device makers also have access to the latest research regarding energy expenditure.

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The problem with using HR in the formula is the degree to which heart rate response to any sub max effort drops as fitness increases. Physiology rather than technology being the limiter. That’s how coming back after an enforced lay off can have you huffing and puffing like Stephenson’s Rocket at a work effort (speed, power output) that would barely count as a warm up intensity after a few months focused training.

In the MD Anderson link, one of the other options for estimating energy expenditure…METs of any activity…is more likely to give a ballpark figure.

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So, even though I can’t get myself enthused over the promises of accurate calorie burn with some iteration of heart rate monitoring, there’s stuff based on calorimetry like with the VO2MAX testing…

No idea whether the accuracy is there enough to be basing weight management decision making on it but the principle is sound. Then there’s the CGMs being pushed for non diabetics…

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As I mentioned earlier, although the heart rate strongly correlates with metabolism, there is so much variation between individuals that there is no one-size-fits-all algorithm for accurately converting heart rate to metabolic rate. What one can say is that if your Fitbit shows that your resting heart rate has declined from a year ago, you can be pretty confident that your resting metabolism has declined. You just can’t be certain about the actual numbers without lab testing.

It is like estimating air temperature by measuring how much people perspire at rest. There is a strong correlation between air temperature and perspiration, so much so that one can be pretty confident that if at rest you are perspiring more than a couple of hours ago, chances are temperatures are rising. However, projecting the actual temperature number is very uncertain because of the degree of individual variation in temperature response.

Two individuals of the same gender and age, one has a much lower resting heart rate than the other. Which would you guess is more likely to have a healthier VO2Max measurement? Resting heart rate can provide information about resting metabolism even if it can’t give precise numbers.

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I was down 50 lbs about two years ago going back 2.5 years. I went into the gym to lift weights. I gain muscle fast. I put back on roughly 5 to 7 lbs out of 13 lost. I have excess muscle from lifting over the years.

You are not wrong but you would be over exaggerating possibly how much it affects me. Muscle in this regard is not my problem.

I am incorporating some resistance now days but only to tighten up my stretching and yoga. You can not only do stretching.

My short period of jogging I tightened up. Now I am looser. The jogging helped my knees with a lot more strength. I am demanding on my body so do not count that as weakness.

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Well, yes, you have said multiple times that heart rate strongly correlates with metabolism…but that doesn’t mean it’s an accurate statement. In fact, the commonly accepted and well studied calculators for estimating BMR (Harris-Benedict, Mifflin St. Jeour etc) don’t use heart rate in their formulae.

Here’s just one explanation from NASM (one of my fitness certifications from Days of Yore ) Information that you will find in any of the standard texts on physiology/exercise science etc and are generally used in wearables to form a basis for their various estimations on calorie burn…hence the apparent lack of accuracy when compared with calorimetry. I imagine that the use of “weight” doesn’t discriminate between, say, a sedentary, 130 lb, 71 yo woman with high bodyfat percentage and a well conditioned, more athletic example like me.

As to your question, all other things being equal and absent modifying pathology or meds (sinus bradycardia or beta blocker usage, for example), the person with lower resting heart rate is more likely to have the higher VO2MAX simply because the lower value is more likely to be a result of good aerobic conditioning…and probably more likely to have a higher BMR because of all the good things that are a result of the athletic conditioning that went to produce that higher VO2MAX, such as a lower bodyfat % and hence greater lean muscle mass etc.

For an isolated example, entering the only stats one online calculator requests … weight, height, age, gender … gives me a BMR of 1126 Cals a day. Changing just my age (to 30 instead of 71) gave me a BMR of 1492…the assumption being a drop in lean body mass activity with age, I imagine. Checking my Garmin Connect app, my low 7 day average RHR of 52 and an estimated VO2MAX of 38 ml/kg/min and all the other proprietary wizardry Garmin uses, my resting energy expenditure is allegedly 1349 Cals a day. Not something I really factor into my daily activities or food planning, BTW…but something that’s fairly typical of long term athletic conditioning, I suspect. During my last enhanced VO2MAX test when I was about 59, my measured VO2MAX was just over 45 and my Resting Energy Expenditure was in the region of 1400 Cals.

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Here’s what looks, on first sight, as a decent breakdown of cardiovascular physiology as it pertains to the body’s energy demands. I’ll dump it here for my own reference purposes as much as for others’ interest.

Quite appropriate in our household right now as dh’s current research is based on working with a group at Virginia Tech who’ve developed a cardiomimetic pump that totally mimics the human heart with cardiac output. Sort of amusing in a macabre sort of way in that the ideas powering husband’s interest (studying sick livers) really started flowing fast after his open heart surgery almost 5 years ago…when he was on cardiopulmonary bypass for a couple of hours. I joke that his version of “Pump Head” awoke all the dormant Good Idea brain cells…and he’s back in Young Turk mode. An anesthesiologist would probably get it😉

Edit: Now I’ve slid partially down the ex.phys. rabbit hole, there’s a whole slew of interesting articles available…which, for anyone interested, will give a better foundation for understanding anomalous-seeming numbers than a short run Gish Gallop. For a start…

https://www.ahajournals.org/doi/10.1161/CIRCRESAHA.117.305205

Edit #2: Here’s one of a series of articles that I used to carry in printed format to hand out to class participants whenever similar topics arose, and time didn’t permit for a whole tutorial on the subject. Useful breakdown of the various interrelated components of the Cals Out/Total Daily Energy Expenditure side of the CI:CO equation…included, but not limited to, NEAT.

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Just for the record, way Way WAy WAY TMI.

:exploding_head:

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Just for the record, my HS chemistry teacher moonlighted at the local hospital in the poop lab.
He said he was the afterhours dookieologist.

:biting_lip:
ralph

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