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The Importance
of Post Exercise Nutrition
During a high intensity, high volume workout, various nutrients are
depleted from the body, and catabolic hormones are also elevated. Both
of these factors are contraindicating to muscular hypertrophy and
performance. The goal of a quality post workout shake is to help
replenish these fuels lost from physical activity, and abate catabolism
(muscle, and nutrient breakdown), and conversely, promote anabolism
(muscle growth, and nutrient replenishment). In order to effectively do
this, we must understand exactly what nutrients are lost during
exercise, and what types of foods and supplements need to be consumed,
in order to maximally replenish these nutrients and abate catabolism,
while concomitantly promoting anabolism. Therefore, this paper is
dedicated to discussing these issues.
This
paper is based on several articles composed in JHR, including
The Window of Opportunity
and
A Scientific Investigation into the Rationality of Post Workout
Carbohydrate Consumption. If
the reader is interested in learning more about this topic, and also,
following up on the references mentioned, they are referred to study
those articles, and others which shall be mentioned throughout this
paper.
Water and
Electrolyte Replenishment
Hydration is the maintenance of plasma volume (the water portion of
blood) in the body. This is done by consuming adequate supplies of water
throughout the day. Evidence suggests that a dehydrated muscle is a
catabolic muscle, and performance will likewise, suffer from
dehydration. Therefore, maintaining myofibril hydration is off the
utmost importance to the serious athlete.
Another important variable to consider is electrolyte replenishment.
Electrolytes are substances which can dissociate into ions in water.
Solutions of electrolytes therefore conduct an electric current and can
be decomposed in a solution (electrolysis). Of particular interest to
athletes, is replenishment of the electrolyte sodium. Sodium constitutes
93% of the cations (positively charged molecules) in the body, making it
by far the most abundant member of this family.
Incidentally, drinks absent or containing little amounts of sodium
post-exercise dilutes blood plasma, increases urine production
(decreased fluid retention), and lowers osmolarity. This further
inhibits the thirst mechanism, and delays rehydration [8, 26, 32, 21,
22], which as previously discussed, is not conducive for growth, or
performance.
For
example, an experiment was performed on six men following strenuous
exercise in the heat [23]. Within 30 minutes after, they ingested one of
four drinks (all with 2045 ml of water) with sodium concentrations of 2,
26, 52, and 100mmol per L of water, respectively. Those who had 2mmol of
sodium excreted almost 800 ml of water 1.5 hours later and almost 1400
ml 5.5 hours later. The best results came with 100 mmol of sodium. Only
300 ml of water was excreted in the first 1.5 hours, and 500 in 5.5
hours—which is less than what those who had little sodium excreted in
1.5 hours!
Typically, a well-assimilated athlete will loose .5L - 3L of sweat
during each hour of exercise. On average, an athlete looses 1-1.5 liters
per hour. Higher intensity exercise results in increased sweat loss.
Humidity, heat, and other weather-related factors will result in
increased sweat secretion, as well. Lastly, every liter of sweat
contains a whopping .6 grams of sodium. This is vital information
to consider, when designing an optimal post-workout shake.
Thus, a proper post workout solution will want to contain both proper
amounts of water and sodium. Recommendations for proper water and sodium
replenishment will be discussed further on.
If
the reader is interested in studying the importance of water and sodium
further, or studying the references cited here, refer to Wilson G.
(2003),
Sodium - A
comprehensive Analysis
and
Effect of Plasma
Volume on Myofibril Hydration, Nutrient Delivery, and Athletic
Performance.
Glycogen
Replenishment
Glycogen is the storage form of the carbohydrate glucose. Evidence
suggests that as exercise intensity increases, your body has a greater
reliance on carbohydrates; particularly, muscle glycogen. During high
intensity exercise (exercise above 85% of your vo2 max) evidence
suggests that 75% of your fuels come from carbohydrates, 80% of which is
supplied by muscle glycogen (see,
Direct Comparisons of Fuel use during Low, Moderate, and High Intensity
Exercises for references on this).
Accordingly, there is a direct correlation between glycogen depletion,
and rate of perceived exertion, as well as decrements in performance.
Since glycogen stores are limited (the typical human can store 400-625
grams of muscle glycogen and about 100 grams of liver glycogen (Inouye,
2006)), and high intensity exercise (such as resistance training) is
highly dependent on glycogen stores, it is clear why another vital
component of post exercise nutrition, is glycogen replenishment.
In
this context, studies have found that the athletes who consume a
combination of easily digested carbohydrates and proteins post exercise,
doubled glycogen synthesis rates in comparison to a carbohydrate only
meal (Van Loon et al., 2000). Another study found that athletes who
consume a combination of carbohydrates and easily digested whey proteins
immediately post exercise lengthened their time to exhaustion on a
subsequent workout by 55%, and had a 128% greater glycogen storage in
comparison to a carbohydrate only beverage (Williams et al., 2003)!
Again, for references, refer to the post workout nutrition articles
mentioned above.
Therefore, athletes will want to consume both carbohydrates and proteins
post exercise, to optimize glycogen replenishment.
Concerning which carbohydrates to consume, evidence suggests that a
50/50 combination of Dextrose and
Maltodextrin is optimal for glycogen replenishment. For the
theoretical rational behind this recommendation refer to,
Dextrose, Maltodextrin, and Sodium an In Depth Analysis
as
well as,
Pre Contest Week - An In Depth Analysis.
This
will want to be accompanied by an easily digested, high quality source
of protein. For these purposes,
Whey Protein is optimal to consume post exercise.
Abating
Catabolic Hormones
All body builders
have a sworn mortal enemy—cortisol. This hormone acts to breakdown
muscle tissue, and creates a catabolic environment, contrary to growth.
The question is:
what is the effect of exercise intensity on cortisol?
Davies (1973)
examined the effect of duration and intensity on plasma cortisol levels.
It was found that as duration and intensity increased, cortisol
increased (though there is a threshold, and this is threshold is
dependent on blood glucose levels. Refer to
Slow Acting Hormones and their Role in Fuel use during Exercise
for more information).
Other hormones, such as glucogon and catecholamines, which also are
catabolic hormones that work to breakdown nutrients, are also released
linearly with exercise intensity.
With
this in mind, these hormones are collectively referred to as counter
regulatory hormones, because they
promote the
release of glucose from muscle, as well as the hepatic system (liver).
Evidence suggests
that the most effective way to abate these catabolic hormones, is to
consume an easily digested carbohydrate, that will rapidly increase the
amount of glucose in the blood stream, and also, stimulate the hormone
insulin, which is an anabolic hormone that acts to stop the catabolism
of nutrients, while concomitantly facilitating the anabolism of several
nutrients, such as the formation of glucose, into muscle glycogen. This
process is further augmented when stacked with an easily digested source
of protein, which as discussed above, has a synergistic effect with
carbohydrates on glycogen replenishment. Proteins also increase the
insulinogenic response of a carbohydrate meal, further attenuating
catabolism.
Protein
Synthesis and Degradation
Skeletal muscle protein synthesis can be defined as the formation of
whole muscle proteins, from individual amino acids. In other words, it
means muscle growth! Conversely, protein degradation can be defined as
the breakdown of proteins, into individual amino acids and peptides. In
other words, it means muscle loss.
With this in mind,
while protein synthesis is elevated up to 48 hours following an exercise
session, protein degradation is also increased; resulting in a negative
protein balance if additional nutrients are not supplied
(Phillips et al., 2005). Furthermore, in order to take advantage of
these elevated levels of protein synthesis, an adequate amount of
nutrients will need to be provided. In this context, post workout amino
acid feedings are critical to muscle protein accretion (growth). For
instance, Biolo, Tipton, Klein, and Wolfe (1997) investigated the effect
of infusing amino acids at rest and after exercise. They found that
while amino acid concentrations increased similarly in both conditions,
that muscle blood flow was 64% greater after exercise than at rest.
Further this corresponded with a 30-100 % increase in amino acid
transport when compared to rest. There was also a greater increase in
skeletal muscle protein synthesis after exercise than at rest (291 % vs.
141 %).
Studies indicate that consuming protein itself is generally responsible
for enhancing protein synthesis; while carbohydrates play an intricate
role in decreasing protein degradation. The role carbohydrates play in
protein synthesis is in debate. However, it appears that when easily
digested carbohydrates are accompanied with proteins, the enhanced
insulinogenic effect from these nutrients may directly enhance protein
synthesis. Either way, to optimize protein synthesis, and decrease
protein degradation, a combination of proteins and carbohydrates is
optimal.
For
more information on protein, and relevant references, refer to
The Ultimate Protein Guide! You can also read our peer reviewed
manuscript on protein here,
http://www.abcbodybuilding.com/proteinaccepted.php
Nutrient
Timing—The Window of Opportunity
Studies indicate that there is a short window of opportunity post
exercise, in which glycogen replenishment and protein synthesis is
optimized. Therefore, if athletes wait to long to consume their post
workout shake, this window of opportunity will be gone.
The Window of
Opportunity and its impact on Glycogen Replenishment.
Evidence is clear that if carbohydrates are not consumed in a timely
manner post exercise, glycogen replenishment is hindered.
For
instance, Ivy et al. (1988) investigated the time of ingestion of a
carbohydrate supplement on muscle glycogen storage post exercise.
Participants consisted of 12 male cyclists. The apparatus consisted of a
cycle Ergometer. Two experimental conditions were utilized. In the first
condition participants exercised continuously for 70 minutes at 68 % V02
max, which was interrupted by 6, 2 minute intervals at 88 % V02 max.
Upon completion of exercise, participants consumed a 25 % carbohydrate
solution. In condition two, the same exercise protocol was used.
However, the CHO drink was delayed for 2 hours.
Comparison of muscle glycogen resynthesis among conditions found that
the rate of
glycogen storage was greater in the immediate condition following the
induction of the CHO solution than in the delayed condition by 45 %.
Therefore, a slower rate of glycogen storage occurred in the delayed
condition, even though insulin levels rose significantly.
This is one of countless examples showing why the window of opportunity
must be met.
For
more information on this and references, refer to
Pre Contest Week - An In Depth Analysis.
The Window of
Opportunity and its impact on Performance, Protein Synthesis and Muscle
Growth
Similarly to studies on glycogen replenishment, studies clearly indicate
that if protein is not consumed immediately upon cessation of exercise,
performance, protein synthesis, and ultimately, muscular hypertrophy,
will be hindered.
The
importance of having a fast digesting protein right after a workout was
demonstrated by Esmarck et al. (2001), who investigated the effect of
immediate and 2 hour delay feedings of protein on muscle hypertrophy and
strength over a 12 week period of resistance training in elderly males.
An oral supplement of 10 grams of protein, 7 grams of carbohydrate, and
3 grams of fat was administered. Results indicated that both mean fiber
area and quadriceps cross sectional area increased in the immediate
protein condition, where as no significant differences were found in the
2 hour delay condition. Both dynamic and isokinetic strength increased,
by 46 and 15 %, respectively in the immediate condition, whereas the
delayed condition only improved in dynamic strength, by 36 %.
As an additional
comparison Levenhagen et al. (2001) administered an oral protein
supplement (10 g protein, 8 g carbohydrate, 3 g fat) either
immediately (EARLY) or three hours after moderate intensity exercise
(LATE). Results indicated that Net balance was significantly more
positive during EARLY, compared with LATE, for isoleucine,
leucine, lysine, phenylalanine, proline, valine, BCAA, EAA,
and NEAA. In fact, while there was a net uptake of BCAA, EAA, and NEAA
with the EARLY condition, there was a net release of BCAA, EAA, and NEAA
in the LATE condition. Further leg protein synthesis was more than
3 times greater in the EARLY condition than the LATE
condition. Finally whole body protein deposition was greater in the
EARLY condition than the LATE condition.
Again, refer to the aforementioned protein article for references.
Tapering the
Solution
Research has pointed to increased recovery by intermittent consumption
of glycogen synthesis recovery drinks (14, 26). Therefore, we advise
tapering the post workout solution over
45-60 minutes.
This will help maximize nutrient absorption and decrease fat gain.
For
more information on this refer to essay 6 in,
A Scientific Investigation into the Rationality of Post Workout
Carbohydrate Consumption.
Supplements
So far, it has
been demonstrated that an athlete needs to consume the carbohydrates
maltodextrin and dextrose, whey protein, water, and sodium immediately
upon the cessation of physical activity. In addition to this,
incorporating several other supplements would also be advantageous. The
following section will analyze must have, post exercise supplements.
Chromium:
See:
13 Weeks To Hardcore Fat Burning - The Diet
Muscular insulin
sensitivity can be defined as the capacity of the muscle cell to take in
and utilize glucose for energy, or for the storage of muscle glycogen.
Muscular insulin resistance (a decreased capacity to absorb glucose)
will therefore, lead to fat storage, and impaired glycogen
replenishment. In this context, Chromium has been found to increase
insulin sensitivity and the lack there of will do the opposite. Based on
the current literature, we advise consuming a 200-400 mcg tablet of
chromium post exercise.
L-Glutamine:
Glutamine is a
conditionally essential amino acid; meaning that under normal conditions
your body produces adequate amounts of it. However, under severe stress
(such as a vomiting-inducing session of squats), your ability to produce
this amino acid falls well short of your bodily needs. For instance,
Keast et al. performed a great experiment to examine the effect of
exercise on plasma glutamine concentrations. Group 1 consisted of seven
randomly selected male athletes who utilized a treadmill at 0, 30%, 60%,
90% and 120% of their VO2 max. The latter group was composed of five
advanced male athletes. They performed two gut-wrenching interval
training sessions per day for ten days, followed by a six-day recovery
period. Glutamine concentrations dropped rapidly from 1244 +/- 121 mumol/L
on average to 702 +/- 101 mumol/L after exercise at 90% VO2max (P <
0.05) and to 560 +/- 79 mumol/L at 120% VO2max (P < 0.001). They
concluded that, “Reduced plasma glutamine concentrations may provide a
good indication of severe exercise stress.”
Glutamine has
demonstrated many, attractive attributes to the athlete, including
increase protein synthesis, decreased protein degradation, enhanced
hydration, and improved immune function, among other benefits. Lastly,
glutamine absorption is maximized when accompanied by glucose and
sodium, making post exercise a perfect time to consume this supplement.
Therefore,
consuming glutamine post exercise is vital. For more information on
glutamine, refer to, See:
Glutamine.
Creatine
The ATP-CP (Phospho-creatine)
energy pathway is the first pathway used during high intensity exercise.
Studies indicate that supplementing with creatine can enhance this
pathway, effectively improving exercise performance. Of further
significance to bodybuilders is that creatine also enhances protein
synthesis, by increasing myofibril hydration.
Lastly, creatine
absorption is optimized when accompanied by sodium and glucose, making
post exercise a perfect time to consume this supplement. For more
information on creatine, refer to,
Creatine Monohydrate Supplementation – A literature Review.
Anti-Oxidants
A
manifold of chemical reactions occur within the body as a result of
intense physical training. During both aerobic and anaerobic training,
one such reaction is the occurrence of excess and adverse free radical
production. Furthermore, concentric and eccentric contractions, which
are crucial to exploiting hypertrophy/hyperplasia, appear to enhance
this reaction, known as Exercise Induced Oxidative Stress (EIOS).
Apposite antioxidant supplementation has been revealed through an
abundant amount of studies to aid in counteracting such negative
responses to training. In addition, the post-workout “window of
opportunity” has shown itself to be an exceptional timeframe in which to
administer anti-oxidant supplementation in direct combat of EIOS.
Exercise induced
oxidative stress is a corporal reaction that needs to be counterbalanced
during the body’s peak time of receptiveness to nutrition.
This phase of the
physiques response to extreme physical stress can best be remedied
through appropriate post-workout supplementation.
A proper
post-workout anabolic cocktail relying on the shuttling effects of
insulin and rapid gastric emptying is the
ideal atmosphere for anti-oxidant consumption in the effort to combat
EIOS.
See:
Role of Antioxidant Supplementation in Response to Exercise Induced
Oxidative Stress
Optimal Protein
Intake
Dangin and
colleagues (2003) investigated the effects of various slow and fast
digesting proteins on protein balance in a single delivered bolus. In
their study they compared 22 grams of whey, 33 grams of casein, and 33
grams of whey on protein balance. Each bolus was combined with
carbohydrates and fats. The authors found that the 33 grams of whey
protein promoted the greatest protein balance in both young and elderly
individuals. However, it should be noted that this will vary with
bodyweight. For example, the protein intake mentioned was an average of
33 grams in the high condition. But in reality the authors prescribed to
each participant 0.48 grams of whey protein per kg of bodyweight. In the
British system, this would be translated to about .22 grams of protein
per pound of body weight. Therefore a roughly 200 pound man would have
consumed 44 grams of protein.
We therefore,
recommend consuming at least 0.48 grams of whey protein per kg of
bodyweight post exercise. While LBM may be a better indicator of protein
needs, this study used body weight. Therefore, we advise tailoring this
according to body weight. While this may result in slightly excess
protein needs, that is a better alternative to suboptimal protein
dosages. However, for an individual whose body fat exceeds 25%, it may
be advantageous to choose a somewhat lower dosage. This will have to be
determined by the individual.
Finally, these
dosages should remain the same, whether you are cutting, or bulking.
Optimal Carbohydrate
Intake
Based on the
literature, on a bulk-up plan, we advise the amount of carbohydrates
consuming 5 grams of carbohydrates per every 10 pounds of lean body
bodyweight. Lean body fat would be defined as the bodybuilder’s
bodyweight after they have subtracted their body fat percentage. So a
200lb man would not necessarily ingest 100 grams of carbohydrates post
workout. If his body fat percent were say, 16%, he would instead consume
eighty-four grams post workout. This is calculated by taking the body
weight of 200 lbs times 16% for a calculation of 32 lbs excess body
weight. Subtracting the 32 lbs from the original 200 lbs would allow us
to know the lean body weight, which in this case equals 168 lbs.
On a cutting phase
we advise consuming 2.5 grams of carbs per 10 pounds of lean bodyweight.
The goal here is to consume just enough to suppress cortisol and
replenish glycogen stores, while still catering to a calorie restricted
diet.
Summary and
Conclusions
The
purpose of this article was to demonstrate exactly what nutrients are
lost during exercise, and what types of foods and supplements need to be
consumed, in order to maximally replenish these nutrients, and abate
catabolism, while concomitantly promoting anabolism. Results indicated
that the
carbohydrates maltodextrin and dextrose, whey protein, water, and sodium
should be consumed immediately upon the cessation of physical activity,
tapered over 45-60 minutes to maximize nutrient absorption, and avoid
fat gain. In addition, the incorporation of the supplements glutamine,
creatine, chromium, and anti-oxidants were also found to be
advantageous.
Part 2 of this
series will give explicit recommendations on post workout nutrition, as
well as an easy to use post workout shake calculator. To read this,
click Here.
Keep it Hardcore,
Venom
Vice President of
ABCbodybuilding.com
Venom@abcbodybuilding.com
And
Adam “Old School”
Knowlden
oldschoolabcbbing@gmail.com
President of Biomechanical Engineering/
Editor and Writer, The Journal of Hyperplasia Research
© ABC
Bodybuilding Company. All rights reserved. Disclaimer
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