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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)

#151

Post by justradition »

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…

The hyper rationalist cult on HN has created a race to see who will be the first to claim "this is a fairly poorly executed study".

It really impresses the crowd here if you ignore all limitations introduced by reality, and fail to clearly even assert the requirements that would result in an "adequately executed study."

Bonus points if you finish your shallow skepticism by redirecting the conversation in the direction of your original preheld biases.

Double bonus points if you fail to link to a study that both supports that preheld bias and meets your own standards for how studies should be conducted.

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

#152

Post by knappe »

jr3592 wrote: post #147
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…

> "but hiit also causes a lot of damage in a lot of ways" Please do explain this. Technically weight lifting (muscle hypertrophy) also causes "damage" but in a controlled an beneficial way.

I really think you're being pedantic to the point of detriment. Runner's knee is a very well known condition in, wait for it, runners!

https://www.mayoclinic.org/diseases-conditions/patellofemora...

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

#153

Post by kudokatz »

kazinator wrote: post #133
ralferoo wrote: post #122

Earlier quoted context omitted.

> 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 exe…

As an example of this ...

At LT1 (via lactate measurements) at peak 100k fitness with elite economy (n=1) ratios were roughly 23% fat, 77% carb. FATMAX was near 28% at slower speed. This is via training using the now-standard (at elite levels), high-carb approach for fueling ultra marathons.

So many factors--including gut training and fueling--play into this. Most aren't even aware of the details, and the "we don't need no carbs for performance" folks still generally bury their heads in the sand. For performance, we're seeing huge skews to carb-based energy for endurance that were considered "wild" just 5 years ago.

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

#154

Post by moscoe »

knappe wrote: post #152
jr3592 wrote: post #147

Earlier quoted context omitted.

> "but hiit also causes a lot of damage in a lot of ways" Please do explain this. Technically weight lifting (muscle hypertrophy) also causes "damage" but in a controlled an beneficial way.

I really think you're being pedantic to the point of detriment. Runner's knee is a very well known condition in, wait for it, runners! https://www.mayoclinic.org/diseases-conditions/patellofemora...

Seems to me hiit is a way to avoid these overuse injuries.

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

#155

Post by andriy_koval »

moscoe wrote: post #154
knappe wrote: post #152

Earlier quoted context omitted.

I really think you're being pedantic to the point of detriment. Runner's knee is a very well known condition in, wait for it, runners! https://www.mayoclinic.org/diseases-conditions/patellofemora...

Seems to me hiit is a way to avoid these overuse injuries.

I think runner knee was a bad example.

Sprint running is more sensitive to form in order to avoid injuries, especially in older adults.

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

#156

Post by tacon »

fsloth wrote: post #139
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?

Just ask the orthopedists down the street from any CrossFit box.

Or their journal articles.

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

#157

Post by AaronAPU »

alfiedotwtf wrote: post #82
thesz wrote: post #76

Earlier quoted context omitted.

HIIT is a borderline strength training. Consider Tabata protocol. It is supermaximal effort protocol, participants are required to exert maximum effort repeatedly. The duration of active phase of Tabata is 20 seconds, half of approximately 40 seconds after which maximum performance (power output) drops significantly, because body switches to a different energy system. In my experience, Tabata squats are done in range…

So that’s for building muscle, but what about if you wanted to lose a few kilos and increase endurance for long distance running? What would be the way to go to optimise your time?

The best way to increase endurance for long distance running is to run for long distances.

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

#158

Post by fsloth »

tacon wrote: post #156
fsloth wrote: post #139

Earlier quoted context omitted.

"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?

Just ask the orthopedists down the street from any CrossFit box. Or their journal articles.

Hiit training can use any type of exercise that allows quick change of pace.

The routine in Tabata’s original HIIT work was just cycling.

Crossfit afaik is a more complex affair than just cycling.

So is the risk of injury due to specific movement or the interval quality of the movement?

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

#159

Post by anigbrowl »

tacon wrote: post #156
fsloth wrote: post #139

Earlier quoted context omitted.

"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?

Just ask the orthopedists down the street from any CrossFit box. Or their journal articles.

I don't think this is helpful. Crossfit appears to prioritize speed and # of reps above all else, and is notorious for people doing difficult exercises with terrible form to try to hit those targets. HIIT certainly emphasises intensity of effort and prefers relatively short rest periods between sets, but not at the expense of proper form. eg when I think of cross-fit weight training or callisthenics I think of lots of snatching and jerking, with HIIT I think of moving slowly with form and trying to hold tension at the apex of the movement.

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

#160

Post by danesparza »

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…

light/moderate weight lifting is not "low-intensity active control condition" then?
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