GOOD TIMING
(Please note, this is a very scientific article and may not be of interest to the casual reader)

By Jeffrey R. Stout, Ph.D., CSCS, FACSM

 It’s About Recovery
     To maximize the recovery process, let’s approach our body as a machine with several systems that need to be functioning optimally in order to attain levels of peak performance or increase lean tissue. For our sake, let’s look at the body as four primary systems: bioenergetic, muscular, neural, and immune.  These systems are important (and there are others), but for athletes, emphasis should be placed on these.

 Metabolic Recovery
     In a nutshell, this refers to the replenishment of your metabolic fuel, stored glycogen as well as ATP and phosphocreatine (PCr).  These are the main fuels for anaerobic exercise.  Endurance athletes utilize glycogen as well as stored intramsuclar fat.  In a recent study published in the American Journal of Physiology[i], they found that eating a ‘normal’ diet that consisted of 39% fat was much more efficient at replenishing stored intramuscular triglycerides in comparison to a typical “high-carbohydrate” diet (24% fat) consumed by endurance athletes.  For endurance athletes, fat intake is even more critical for recovery than it is for strength-power athletes.
     Nonetheless, for replacing stored glycogen, the obvious choice would be to consume gobs of carbohydrates.  Remember however that anaerobic athletes don’t expend as much energy as a marathon runner.  Thus, it isn’t necessary to eat a loaf of bread after training.  Instead, a dietary strategy that will work for most anaerobic athletes is combine protein with carbohydrate and a touch of fat.  For the endurance athlete, it is clearly necessary to consume more carbohydrates and fat to promote muscle glycogen and intramuscular triglyceride restoration.
     Another energy system that needs to be restocked is your stored ATP (adenosine triphosphate) and PCr (phosphocreatine).  In this case, creatine is a must.  Though it has no effect on total ATP levels, creatine supplementation will increase levels of PCr and creatine inside your muscle cells.[ii] Increasing levels of PCr in your muscle cells is important for maintaining energy and strength during heavy bouts of repeated lifting. 

 Skeletal Muscle Recovery
     Of course, part of muscle recovery involves the replenishment of fuel (i.e., glycogen, ATP, PCr).  Clearly, this would require the consumption of a post-exercise carbohydrate-protein meal and perhaps supplemental creatine (to replenish stored phosphagens).  Moreover, another aspect involves the recovery of damaged muscle fibers.  Perhaps one strategy (out of many) for dealing with damaged muscle cell membranes is via anti-oxidant supplementation[iii].  When you damage muscle cells, you are in essence left with a lot of junk and debris for your immune cells to clean up.  Think of this scenario as equivalent to a group of janitors arriving to clean up a mess.  But in addition to cleaning up the original mess, these janitors (neutrophils and monocytes, types of immune cells) also tend to tear down the walls as they clean.  Anti-oxidant vitamins like vitamin E[iv] and vitamin C may combat this aggressive cleaning strategy of the janitors (part of the acute phase response) both by buffering the reactive oxygen species that are released and by suppressing cell membrane peroxidation and prostaglandin formation, which is partly responsible for the inflammation.  What this means in plain English is that anti-oxidants will help repair and clean up the crap left over from torn up muscle fibers.  Though vitamin C and E are important anti-oxidants, it’s best to get these from foods.  We’d recommend supplementation if your diet is poor or inadequate. 

 Neural Recovery
     Some scientists have proposed that fatigue during prolonged exercise may be related in part to exercise-induced alterations in the central nervous system (i.e., the brain).[v]  According to this theory, known as the central fatigue hypothesis, as muscle glycogen levels decrease during exercise, there is an increased oxidation of fat and the branched chain amino acids (BCAA) as fuel.  Therefore, free fatty acid (FFA) levels in the blood start to go up whereas the availability of BCAA in the blood decreases.  The increase in FFA levels in the blood is accompanied by a release of the amino acid tryptophan from its binding protein (albumin) thus increasing the level of free tryptophan in the blood.  OK…so what the heck does all this BCAA, tryptophan have to do with fatigue?
     Well as you increase levels of tryptophan in the brain this in turn promotes the formation of the neurotransmitter 5-hydroxytryptamine (serotonin).  Increased levels of serotonin in the brain and peripheral tissues have been reported to induce sleep and basically make you tired.  So is the answer taking lots of BCAA?  The evidence at this moment isn’t complete though it might be a strategy worth trying.  Perhaps a better strategy would be to take supplemental glucose during a prolonged session of training or during competition that last more than an hour. 
     Another amino acid that might benefit neural recovery is tyrosine.[vi]  Taking tyrosine prior to or during your training bout, may help your performance by decreasing your perception of fatigue.  Here’s how it works.  We know that physical and mental stress can lead to significant decreases in norepinephrine (a neurotransmitter) concentrations in the brain.  There is in fact a direct correlation between low norepinephrine levels and a decrease in physical performance.  Tyrosine supplementation may combat this drop in norepinephrine levels.
     Interestingly, many of the studies done on tyrosine have been on military personnel.  For instance, army personnel given tyrosine show less of a decline in physical performance and less mental stress than those given a placebo.  This doesn't necessarily mean that taking tyrosine will make you stronger; however, it may work best if you’ve been under a lot of stress, are overtrained, or perhaps sleep-deprived. 

Immune Recovery
     There are several ingredients that may benefit your immune system: they include carbohydrates, whey protein, glutamine, vitamin C, and omega-3-fats. 
     According to a study by Gleeson et al.[vii] “an athlete exercising in a carbohydrate-depleted state experiences larger increases in circulating stress hormones and a greater perturbation of several immune function indices. Conversely, consuming carbohydrate during exercise attenuates rises in stress hormones such as cortisol and appears to limit the degree of exercise-induced immunosuppression, at least for non-fatiguing bouts of exercise.”  This clearly applies to those who engage in prolonged endurance exercise as well as those who are severely restricting carbohydrate intake (e.g., pre-contest dieting).
     Research in whole animals as well as under test-tube conditions suggest that whey protein concentrate can produce improvements in the immune response.  Animals fed whey protein concentrate show an enhanced immune response.[viii]  Whey protein appears to raise glutathione levels in animals and humans, and may be a mechanism of modulating immunity. It is certainly worth examining as a supplement that could help your overall health.
     Plasma glutamine decreases by 20% one hour after a marathon race.  Athletes who ingest glutamine report fewer infections post-exercise versus athletes who do not supplement with this wondrous amino acid.[ix]  Though your training session may not be as difficult as running 26.2 miles, repeated bouts of intense exercise over the course of many hours or days might have similar effects on the immune system.  Taking supplemental glutamine might serve as an insurance policy against feeling run-down and lethargic.
      Vitamin C supplementation can effectively reduce the rate of upper respiratory tract infection after extensive physical stress.[x]  Also, vitamin C can also combat the harmful effects of free radicals that released by white blood cells when they eat up the cellular junk and debris of your body (i.e. as seen in damaged muscle cells).  If you let those free radicals rampage around your body causing damage to your cell membranes, like those surrounding your muscle cells, this could impair your ability to recover and accrue muscle tissue. 
      In ill patients, omega-3-fats has been shown to boost immune function.[xi]  Granted, most active individuals aren’t ill and stuck in a hospital bed But getting adequate omega-3 fats (either from fish oil or eating fish) is important for overall health.  If omega-3 fats can help prevent potential illness because of its positive effect on the various fractions of T-lymphocytes, then this means less time off from training.  And in the long run, that means you adapt better to exercise training.

  How to Feed your Muscles

What's the most important nutritional consideration for maximizing the adaptive potential of muscle? The answer: Total daily energy intake.  There are a few requirements for high rates of tissue turnover and they're all dependent on a high energy input. High rates of tissue turnover are very energy expensive so extra calories are needed to run this circuit. You see, your time in the gym, on the track, or on a hilly hiking trail is also very energy expensive as is the hypermetabolism and muscle repair that follows exercise.  If the body doesn't get adequate energy supplies (in the form of calories), it obviously can't optimally perform all the functions of exercise, repair, and tissue turnover.
     The first system to suffer in this equation will be your tissue turnover rates. If you don't eat enough daily calories, this system will slow down so that less energy is needed and the energy to fuel the workout and recovery is provided by the destruction of tissues. But in this case, remodeling suffers.  Interestingly, this has implications for your body composition/body fat as well as muscle function. The loss of weight isn't always an indicator of inadequate calorie intake. As described above, the body will slow down tissue turnover in response to under eating. Since tissue turnover is expensive, your energy needs decrease and you remain weight stable. However, as mentioned, your tissue remodeling will suffer.
         When you increase calories, the first thing to occur will be the increase in tissue turnover rates. This will dramatically raise calorie needs. Depending on your calorie intake, you may end up either losing weight (turnover increases more than calories), remaining weight stable (turnover matches calorie intake), or increasing muscle weight (turnover is less than intake). But the benefit here is that when tissue cycling rates are high, even if you're losing weight or remaining weight stable, the body is being remodeled in a positive and functional way. Again, the key is a high calorie intake.

 Post-Workout Recovery Nutrition

The next important nutritional issue to address is recovery nutrition. The provision of liquid nutrients during and after exercise is important for several reasons.  First, an anabolic environment is created, as the exercise and insulin signals are both stimulating cellular activity.  Second, such nutrition can shift the net protein status in a positive direction so that muscle protein is being built in and around the workout. Third, muscle recovery is superior due to replenishment of muscle substrates.  And fourth, nutrients are rapidly delivered for energy provision when it's most needed. 

Timing is Everything!

Imagine speeding at 95 mph down a desolate highway in your vintage red Corvette and noticing you just drove by a state trooper, now that’s bad timing! Or imagine looking at your lottery ticket and realizing you just picked the correct 6 numbers, that’s good timing (and luck)!  Well, this applies to exercise.  After endurance, strength or power training, the body is primed for nutrient uptake into the muscle cells. So what should you feed your hungry muscles?  Well, the abundance of new research has provided clues as to what to consume after the workout. 

There are three simple, practical principles that every fitness enthusiast, bodybuilder, or performance athlete can incorporate into his/her daily training to boost recovery and maximize the benefits of exercise.   These principles include:

1. The Restoration of Electrolytes and Water

            Fluid and electrolyte replenishment is crucial in maintaining cardiac output and regulating body temperature during exercise.  Also, post-workout, maintenance of a hydrated state aids your body in burning fat.  So stay hydrated!

2. The Rapid Replenishment of Skeletal Muscle Glycogen Stores

Early studies primarily focused on replenishment of glycogen stores by consumption of a carbohydrate supplement both during and after exercise. Carbohydrate supplementation stimulates insulin.  Insulin has two major roles: 1) Facilitates the transport of glucose into the muscle cell; (2) Stimulates enzymes responsible for the synthesis of glycogen from glucose.  Recent evidence has shown however that adding protein to the mix is even better for glycogen repletion.

3.  The Provision of Amino Acids to Aid Muscle Protein Synthesis and Accretion

Immediately following exercise a rebuilding process is initiated to repair muscle fibers damaged during exercise. Evidence suggests that insulin is a strong stimulus of this muscle rebuilding process; insulin facilitates glucose and amino acid transport into the muscle cells or fibers as well as diminishes the breakdown of muscle protein.  This interrelationship between glycogen replenishment, insulin and muscle rebuilding is a cornerstone of muscle recovery. 

            Thus, the consumption of protein, glutamine and branched chain amino acids are warranted.  Protein not only stimulates the replenishment of glycogen stores by activating insulin, but also provides the essential building blocks for muscle repair.  I believe it’s the essential amino acid component of protein that’s critical for muscle repair and recovery.