BE­GIN HERE

Main­tain mus­cle mass as you age through smart train­ing and diet.

Climbing - - CONTENTS - BY BETH BEN­NETT

Mus­cle is con­stantly be­ing bro­ken down (mus­cle pro­tein break­down; MPB) and re­built (mus­cle pro­tein syn­the­sis; MPS). Mus­cle loss oc­curs when the bal­ance tips to­ward break­down. How is mus­cle pro­tein built? The ac­cepted wis­dom is that you need a lot of pro­tein, es­pe­cially an­i­mal pro­tein. Ac­tu­ally, our bod­ies can syn­the­size most amino acids—the build­ing blocks of pro­tein—from smaller con­stituents in most foods. We do need to get some amino acids—es­sen­tial amino acids (EAA)—from diet. The EAAs from an­i­mal sources match our needs most closely, but you can also mix and match plants. Then, ge­netic in­struc­tions are fol­lowed for build­ing spe­cific types of mus­cle pro­teins (e.g., fast- and slow-twitch fibers).

When you work your mus­cles, they burn fuel to con­tract— much like a car burns gas. Both pro­cesses also pro­duce pol­lu­tants. The dam­age to the mus­cle cell stim­u­lates built- in re­pair pro­grams that build and strengthen the mus­cle. The catch is that you have to have amino acids handy for the buildup, though if you con­sume too many, they get stored as fat ( see “Eat to Build Mus­cle”).

In ac­tive in­di­vid­u­als like climbers, what changes with age is the abil­ity to build mus­cle af­ter con­sum­ing pro­tein. In what phys­i­ol­o­gists call an­abolic re­sis­tance, our mus­cle cells get worse at pulling pro­tein build­ing blocks out of the blood and us­ing them. No one is re­ally sure why, but it seems to be due to our mus­cle stem cells de­te­ri­o­rat­ing as they age. Mean­while, if you don’t use your mus­cles, MPS drops off so much that this de­cline alone ex­plains age-re­lated loss.

To main­tain mus­cle mass, we need to max­i­mize MPS and min­i­mize MPB.

EAT TO BUILD MUS­CLE

The mus­cle-loss part of the equa­tion ac­cel­er­ates around age 50. Be­fore that, your mus­cle cells are still pretty good at us­ing EAAs. Re­cent find­ings sug­gest that in­di­vid­u­als <50 should be eat­ing 0.7–0.8 grams of pro­tein per kilo of body weight per day, while the >50 crowd should aim for 1–1.3 grams. This trans­lates to 60 grams of pro­tein for a 150-pound guy in his 40s, and the same if you’re a 115-pound sex­a­ge­nar­ian like me. ( See “Tips.”)

An eas­ily di­gestible pro­tein such as whey, found in many pro­tein pow­ders, can fur­ther stim­u­late MPS. The most im­por­tant EAA for jump­start­ing MPS is leucine. Leucine is an ini­tia­tor for a chain of events that cul­mi­nates in pro­tein syn­the­sis. How­ever, the stronger that sig­nal, the greater the chance of stim­u­lat­ing can­cer cells. Re­search has shown that high pro­tein in­take—more than 10 per­cent of daily calo­ries from meat and dairy, but not plants—ear­lier in life (ap­prox. 50 and younger) re­sulted in big in­creases in can­cer and di­a­betes later.

MOVE TO BUILD MUS­CLE

Mod­er­ate to se­vere ex­er­cise will in­crease both MPB and MPS. Eat­ing a high-pro­tein meal post-work­out will in­crease MPS but de­crease MPB. In both young (20 years) and older (50 years) ath­letes, ex­er­cise fol­lowed by 20 grams of good-qual­ity pro­tein in­creased MPS com­pared to ex­er­cise with­out pro­tein in­take af­ter­ward. More good news: Re­sis­tance ex­er­cise—weight train­ing or climb­ing—can en­hance the MPS re­sponse to pro­tein con­sump­tion for days af­ter the work­out. Trans­la­tion: You likely don’t need to eat that pro­tein im­me­di­ately.

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