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Exercise intensity influences body composition in healthy older adults (2025)

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Re: Exercise intensity influences body composition in healthy older adults (2025)

#131

Post by all2 »

deeth_starr_v wrote: post #116
JumpCrisscross wrote: post #105

Earlier quoted context omitted.

You may want to talk to your doctor about potential exercise-induced cardiac remodeling. Not an expert on this at all. But it’s an injury mode that’s been recently characterized due to sudden deaths among young, seemingly-healthy sprinters.

Very interesting. I can also get Afib after many years of high intensity exercise

This happens to me occasionally, but it's typically stimulant and blood sugar related.

There are some indications that it might be related to ion availability in your body, so copper, zinc, and calcium specifically. You may also consider that HF RF found in phones, wifi, and Bluetooth can do not great things to the calcium channels in cell walls (it essentially locks the channels open in some cases).

There are a lot of factors to this, but these are things I've picked up in my reading for my own issues.

Re: Exercise intensity influences body composition in healthy older adults (2025)

#132

Post by shermantanktop »

tryagainian wrote: post #121
lol8675309 wrote: post #79

'were small and not meaningful' why is this on the front page of HN?

The perennial question. Well, at least it’s spurred intellectually curious discussion.

Is it? What I mostly see is people describing their anecdotal experience and opinions about exercise in general.

I assume that only a few of them are actually in the age group of 65-85, so relevance of personal experience is dubious.

To be fair there are some questioning the study methodology and conclusions.

Re: Exercise intensity influences body composition in healthy older adults (2025)

#133

Post by kazinator »

ralferoo wrote: post #122
bitexploder wrote: post #114

Earlier quoted context omitted.

"If you do aerobic exercise, almost all the energy comes from burning fat. " This is directionally incorrect. Your body will burn both concurrently. For low intensity aerobic exercise, fat is used as the dominant energy source. However even at moderate intensity levels like jogging and "zone 2" aerobic you are 50/50. At higher intensity you have crossed the inflection point and are using more glycogen than not. All s…

> This is directionally incorrect. Your body will burn both concurrently. For aerobic exercise, your body gets around 95% of the energy from burning fat. If you are doing exercise where you are 50/50, then it is by definition no longer aerobic exercise but anaerobic. Anaerobic exercise starts at the point that your body is forced to use glucose from glycogen to provide energy because you have reached the limit of the…

There are two exercise intensity thresholds related to respiration: VT1 and VT2 (ventilatory threshold).

Everything from minimal activity far below VT1 to VT2 (a.k.a. "lactate threshold", LT, a.k.a. "anaerobic threshold", AT) is "aerobic".

Near the VT2 limit, very little fat is used compared to glucose. Fat burning proportions as high as 95% are only reached under very light activity. (And/or in glycogen depleted exercisers whose body has switched to fat out of necessity). That doesn't represent the entire aerobic range.

There is aerobic use of glucose (below the lactate threshold, "clean burning") and anaerobic (above AT, generating lactic acid).

A useful parameter is the absolute fat burn rate. Maximal fat burning does not occur at exercise intensities that derive a large proportion of energy from fat. Supposedly, this "FatMax" exercise intensity fairly closely coincides with the VT1 threshold. Here, around 60% of the energy comes from fat.

I'm "fat checking" all this as I type; I used to know more about this stuff, but forgot a lot.

Re: Exercise intensity influences body composition in healthy older adults (2025)

#134

Post by AnimalMuppet »

proee wrote: post #93

So warning about super-high intensity workouts. For a good while I would sprint hard as possible up 8 flights of stairs everyday instead of taking the elevator. I would do this multiple times per day (3,4 sometimes 5) with no warm-up/cool-down . Each time I would try to push for a PR, figuring might as well go for it! One day, after about a year of doing this, I noticed my heart rate at the top felt a little off. I t…

> FYI I'm in my 40's.

Bad news: Age is a risk factor for AFIB. The older you get, the more likely it is to happen.

Re: Exercise intensity influences body composition in healthy older adults (2025)

#135

Post by proee »

AnimalMuppet wrote: post #134
proee wrote: post #93

So warning about super-high intensity workouts. For a good while I would sprint hard as possible up 8 flights of stairs everyday instead of taking the elevator. I would do this multiple times per day (3,4 sometimes 5) with no warm-up/cool-down . Each time I would try to push for a PR, figuring might as well go for it! One day, after about a year of doing this, I noticed my heart rate at the top felt a little off. I t…

> FYI I'm in my 40's. Bad news: Age is a risk factor for AFIB. The older you get, the more likely it is to happen.

Also a significant increase in AFIB risk for runners. I am doing around 10-20MPW over the last 5 years. Not sure if this is enough training load, but I've had a habit of pushing too hard on my runs as well.

Re: Exercise intensity influences body composition in healthy older adults (2025)

#136

Post by Schiendelman »

nubg wrote: post #96
Systemerror7A69 wrote: post #48

I think it's important to note that this study, at least to my understanding, compared cardio training - not weightlifting or resistance training. Participants did 3 weekly sessions of either low intensity, moderate treadmill excercise or HIIT ( 4-min @ 85–95%, 3min 60-70% ). I get the feeling some commenters here are misunderstanding this as a lot of the discussions seems to center about weightlifting. Additionally…

can you tldr me if weightlighting will put me roughly in the "hiit" group discussed in the paper, and give me its benefits?

No, you also need cardio. Even if your heart rate goes up while lifting, it's sustained cardio that really improves your cardiovascular health, keeping your heart rate up in zone 2+ for 45+ minutes at a time a few times a week.

Re: Exercise intensity influences body composition in healthy older adults (2025)

#137

Post by personalityson »

Insulin -- the fat storing hormone. The opposite hormones -- cortisol and adrenaline mobilize fat tissue for burning. Chronic cortisol leads to fat gain because cortisol receptors become desensitized. Spiking cortisol in short bursts is better than long bouts of elevated cortisol.

Re: Exercise intensity influences body composition in healthy older adults (2025)

#139

Post by fsloth »

yawnxyz wrote: post #113

> Healthy older adults (n = 123, average age 72.0 years, body mass index 25.8 kg/m2) completed three 45-min supervised exercise sessions per week for 6 months. Participants were randomised to treadmill-based moderate-intensity training (n = 45), or high-intensity interval training (n = 41) or a low-intensity active control condition (n = 37), with individualised heart-rate prescription. Dual-energy x-ray absorptiomet…

"hiit also causes a lot of damage in a lot of ways"

Oh! I didn't know about this. Are there any references you could quote?

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