This article will address a specific question, and – at times (as Tyler’s style dictates) can get a bit wordy and possibly confusing.
The question involves the physical state of ‘Anabolism’.
You will read about numerous applications for enhancing muscle growth and repair as well as some ‘myth-debunking.’ So stay tuned!
Tyler’s question is not “what is the Anabolic Window?” – but one that goes beyond simply defining the term. The information provided plums the depth of this subject.
> so what is this question? …
“Is the Anabolic Window Real?”
If you’re well informed in the fitness industry, you’ve likely heard of the anabolic window and know the old saying; “nutrient timing is everything, if you want to build muscle!”
However you’ve likely also learned that more recent research has somewhat debunked this “anabolic window” theory – in favour of simply meeting total daily nutrient requirements.
If you’re not optimizing your post-workout nutrition properly, you may very well be missing out on some potential ‘gains’.
If you really want to know the truth about the “anabolic window” and post-exercise nutrition, you want to read this article…
This much is undisputed.
The data is very clear on the benefits of enhanced protein synthesis, attenuating protein breakdown, and ultimately contributing to muscle growth and repair. However it is the timing of ingestion that has been a topic of heated debate. In some cases, the timing of nutrient ingestion is thought to be more important than the nutrients…
In a nutshell, proper nutrient timing means: ‘optimizing the delivery of nutrients to the muscle during a time when the muscle is primed to use them most effectively.’
Nutrients and Exercise
Resistance exercise training is a reference point commonly used as a basis for the timing of nutrient ingestion due to the metabolic effects of exercise.
The time frame immediately prior to and during exercise is the phase primarily devoted to the use of the body’s energy to improve the quality of the workout. However, this period of time is not consistently associated with enhancing muscle growth after exercise – but it should be –
During exercise and immediately after exercise, the body is in a Catabolic state.
- Blood insulin is low, while cortisol and other catabolic hormones are high.
- Liver glycogen levels are reduced, or in some cases depleted.
- The rates of muscle protein breakdown is at it’s highest.
While resistance exercise itself is known to be an activator for protein synthesis, the absence of any post-exercise nutrition will leave the body in a net catabolic state.
This is because any increase in protein synthesis (creation) is offset by the high rates of protein breakdown (catabolism). This catabolic state can prevail for many hours until nutrients are consumed. Therefore, exercise without any post-exercise nutrition is not a favorable situation for muscle growth.
The consumption of protein and carbohydrates initiates a shift to anabolism by simultaneously reducing all the catabolic factors and amplifying the effects of protein synthesis.
One possible mechanism is that muscle is particularly sensitive to insulin post-exercise, which ensures:
- the rapid transport of glucose and amino acids into muscle.
- promotes muscle glycogen synthesis and protein synthesis.
- inhibits the pathways governing protein breakdown.
Since insulin sensitivity declines with time, the effectiveness of nutrient intervention will also decline along with it.
Although the muscle sensitivity is known to be elevated for up to 48 hours post-exercise, muscle sensitivity is greatest within the first 3 hours and then progressively declines.
The ingestion of protein post-exercise primarily serves to augment the rates of protein synthesis – but only plays a minor role in stopping the effect of protein breakdown.
Surprisingly, there are very few studies that have analyzed the protein synthetic response of various time-points post-exercise. The general consensus is that there is a clear additive effect of protein synthesis when protein is ingested within the first few hours post-exercise.
Thinking logically however, the sooner the muscles transition from catabolism to anabolism, the greater the potential for muscle growth.
For this reason, while there may not be a clear narrow window when nutrient ingestion is required, most exercise studies clearly support protein supplementation sooner rather than later for the optimal stimulation of protein synthesis.
Most weight-lifting athletes primarily focus on protein supplementation post-exercise, with concern mostly on protein synthesis, and with little regard to the need for carbohydrates.
As previously mentioned, protein supplementation focuses on pathways to stimulate protein synthesis and does not have a major affect on protein breakdown. However, the ingestion of carbohydrates post-exercise has a major impact on the effectiveness of the cellular pathways that involve protein breakdown.
Including carbohydrates during post-exercise nutrition plays a prominent role in the transition from muscle catabolism to anabolism.
Glycogen levels in muscle influences the activity of a number of metabolic activities including glucose transport and protein metabolism. That means the restoration of muscle glycogen is paramount in the exercise recovery process.
The combination of carbohydrates with protein results in greater gains in muscle hypertrophy after resistance training when compared with a protein-only supplement.
Timing of carbohydrate supplementation appears to be more stringent than it is for protein.
Post-exercise muscle glycogen synthesis occurs more rapidly when carbohydrates are consumed immediately after exercise as opposed to waiting several hours.
In fact, delaying supplementation for two hours can reduce the rate of muscle glucose uptake and glycogen synthesis by half.
If carbohydrates are not adequately supplied post-exercise, the rate of muscle glycogen synthesis can be extremely low despite normal increases in blood glucose and insulin levels later in the day.
Protein and carbohydrate supplementation post-exercise is a vital component to optimizing post-exercise muscle recovery.
This includes not only maximizing muscle hypertrophy, but also minimizing muscle soreness and optimizing muscle recovery time.
The combination of these nutrients increases the efficiency of muscle recovery when compared to either carbohydrates or protein alone.
Any delay in supplementation post exercise is not recommended, as the muscle remains in a catabolic state until nutrients are delivered to them.
Furthermore, the sensitivity of muscle is highest soon after exercise. Therefore, if getting the most out of a workout is crucial, then consuming nutrients soon after exercise should be considered equally as important.
So as you can see, most of the myth-busting about the anabolic window focuses on protein supplementation alone for post-exercise and that’s where most people get it wrong.
As you read above, carbohydrates post-exercise are perhaps even more important for muscle recovery and growth.
This is for you to stay informed, for your health’s sake!