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mccoy

New section on physical exercise for longevity

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FWIW,   excerpt from Brad Schoenfeld's "Science and Development of Muscle Hypertrophy"--the goal being strictly muscle hypertrophy,  not longevity.   (If anyone wants any of the references, let me know.)

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Exercise potentiates the anabolic effect of protein intake, heightening both the magnitude and duration of the response (49). After a brief latency period, dramatic increases in muscle protein synthesis are seen between 45 and 150 min postworkout, and elevations are sustained for up to 4 hours in the fasted state (49). Despite this exercise-induced increase in muscle protein synthesis, postexercise net protein balance remains negative in the absence of nutrient consumption (220). Provision of EAAs rapidly reverses this process so that protein balance becomes positive, and anabolic sensitivity is sustained for longer than 24 hours (49).

 

The essential amino acid leucine, one of the branched-chain amino acids (BCAAs), is believed to be particularly important to the regulation of muscle mass. Leucine has been shown to stimulate muscle protein synthesis both in vitro and in vivo. The mechanism of action appears to be the result of an enhanced translation initiation mediated by increased mTOR phosphorylation (561, 839). This contention is supported by findings that activation of mTOR is relatively unaffected by the other two BCAAs, valine and isoleucine (839).

 

 Leucine also has a positive effect on protein balance by attenuating muscle protein breakdown via the inhibition of autophagy (839). The influence of leucine is limited to the activation of muscle protein synthesis, not the duration; sustaining elevated muscle protein synthesis levels appears to rely on sufficient intake of the other EAAs, especially the BCAAs (578).

 

Some researchers have proposed the concept of a leucine threshold (also termed leucine trigger); they postulate that a certain concentration of leucine in the blood must be reached to maximally trigger muscle protein synthesis (294). Research shows that a 2 g oral dose of leucine (equating to approximately 20 g of a high-quality protein such as whey or egg) is necessary to attain the threshold in young, healthy people (505), although variations in body size would seemingly mitigate this amount.

 

Leucine requirements are heightened in the elderly. The aging process results in desensitization of muscles to EAAs (i.e., an anabolic resistance), whereby older people require larger per-meal doses than their younger counterparts (190). Mechanistically, this is thought to be due to a dysregulation of mTORC1 signaling (see chapter 2), which in turn necessitates a higher leucinemia to trigger elevations in muscle protein synthesis (577).

 

Katsanos and colleagues (353) found that 6.7 g of EAAs— an amount shown to be sufficient to elicit a marked anabolic response in young people— was insufficient to elevate muscle protein synthesis above rest in an elderly group; only after supplementation with 1.7 to 2.8 g of leucine did a robust increase occur. The findings suggest that older people require approximately double the amount of leucine per serving that younger people require to reach the leucine threshold.

 

It should be noted that the dose– response anabolic effects of leucine are maxed out once the threshold is attained; increasing intake beyond this point has no additional effect on muscle protein synthesis either at rest or following resistance exercise (561). Moreover, longitudinal studies in animal models have failed to show increased protein accretion from leucine supplementation in the absence of other amino acids (197, 436). This raises the possibility that supplementation of leucine alone results in an EAA imbalance that impairs transcriptional or translational function, or both.

 

 Alternatively, although leucine supplementation triggers the activation of muscle protein synthesis, the duration may not be sufficient to produce substantial synthesis of contractile elements. Either way, the findings reinforce the need for adequate consumption of the full complement of EAAs in promoting muscular development.

 

Requirements

 

The accretion of lean mass depends on meeting daily dietary protein needs. The RDA for protein is 0.8 g/ kg of body mass. This recommendation is based on the premise that such an amount is sufficient for 98% of healthy adults to remain in a nonnegative nitrogen balance. However, the RDA, although adequate for those who are largely sedentary, cannot be generalized to a resistance-trained population. For one, the maintenance of nitrogen balance indicates that day-to-day protein losses are offset by the synthesis of new bodily proteins; gaining muscle requires a positive nitrogen balance (i.e., protein synthesis exceeds degradation over time). Moreover, intense exercise substantially increases protein turnover, heightening the need for additional substrate. In addition, the nitrogen balance technique has serious technical drawbacks that can result in lower-than-optimal protein requirements (578). Considering the totality of these factors, the protein needs of those seeking to maximize muscle size are substantially higher than those listed in the RDA guidelines.

 

Key Point

It is important to ingest protein, and especially leucine, after resistance exercise to sustain muscle protein synthesis postworkout. Those seeking to maximize muscle size need substantially more protein than the RDA guidelines propose. Older adults require more protein than younger adults do to build appreciable muscle.

 

A number of studies have been carried out to determine protein requirements for those involved in resistance training. Lemon and colleagues (415) found that novice bodybuilders in the early phase of intense training required approximately 1.6 to 1.7 g/ kg/ day— approximately double the RDA. Similar findings have been reported by other researchers (745).

 

This increased protein requirement is necessary to offset the oxidation of amino acids during exercise as well as to supply substrate for lean tissue accretion and the repair of exercise-induced muscle damage (118). The dose– response relationship between protein intake and hypertrophy appears to top out at approximately 2.0 g/ kg/ day (118); consuming substantially larger amounts of dietary protein does not result in further increases in lean tissue mass.

 

There is even some evidence that protein requirements actually decrease in well-trained people. Moore and colleagues (504) found that heavy resistance exercise reduced whole-body leucine turnover in previously untrained young men; an intake of approximately 1.4 g/ kg/ day was adequate to maintain a positive nitrogen balance over 12 weeks of training. The findings suggest that regimented resistance training causes the body to become more efficient at using available amino acids for lean tissue synthesis, thereby mitigating the need for higher protein intakes.

 

Optimal total daily protein intake depends on both energy balance status and body composition. Phillips and Van Loon (578) estimated that a protein intake of up to 2.7 g/ kg/ day was needed during hypoenergetic periods to avoid lean tissue losses. Helms and colleagues (300) made similar recommendations, suggesting an intake of up to 3.1 g/ kg/ day of fat-free mass in lean, calorically restricted people. It has been theorized that the higher protein dosage in this population promotes phosphorylation of PBK/ Akt and FOXO proteins, suppressing the proteolytic factors associated with caloric restriction and thus enhancing lean tissue preservation (478).
 

[emphasis added]

Edited by Sibiriak

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The above literature states some simple points:

 

  1. Beginners who are working out need more protein, > 2*RDA
  2. Well trained strength athletes need less than beginners because of adaptation
  3. Bodybuilders who are conditioning for the context (calorie-restricting) need many more protein, about 3*RDA or more, to avoid excessive muscle mass los

Also, I think that bodybuilders training very often may require unordinately high amounts of protein because of the extreme stress to which skeletal muscle is subject

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Mike, I found just one marathoner among many other former athletes. Maybe that testifies to the fact that extreme endurance is unfavourable to longevity? There is also the issue of performance enhancing drugs. Athletes who have been active before their widespread use tend to be more longeve. Today, probably there are few or no elite athletes who do not make use of some illegal drugs.

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Good point wrt drugs and extremes. Moderation in all things As the old saying goes. For myself I am a beleiver in purposeful exercise. It is one reason I love to garden. It gives me a purpose and it can be a tremendous form of exercise if done a bit vigorously.. lots of muscles are used and its almost yogalike with all the body positions one needs to use to get the job done.

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"The issue which I'm interested into and which has been expressed by Dr Attia during his interview with Rhonda Patrick is if it is possible to increase muscle mass and keep mTOR downregulated. It sure sounds like an oxymoron, but he thinks in therms of targeted upregulation, that is, upregulating mTOR in the muscle tissue and downregulating it in the organs..it might be possible theoretically to hack the body into growing muscles and keeping the other organs in the repair and maintenance mode.."

 

I am interested in exactly the same thing! 

 

Therefore I am working out multiple days a week using low weights but high reps to avoid excessive strain/injury, hitting isolated muscles on different days - the typical bodybuilding approach. SO far I am seeing more muscle definition and increased vascularity although I do not know how much is attributable to my lower body fat and how much to increased muscle. 

I plan on doing another hydrostatic bodyfat test asap to better judge.

So far fatigue has not been an issue except at very low cal days (1000). So I am keeping my daily cal at about 1500 - no ill effects related to the workouts at all yet.

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