Does the Anabolic Window Really Exist?
The post-workout anabolic window is a well-known and discussed phenomenon in the sports and performance world. Everyone and anyone will tell you about the importance of consuming a nutrient balanced recovery meal or drink within a miracle 30-minute period post-workout. But is your workout or training session really useless if you don’t refuel within this time?
Theoretically, consuming the correctly balanced recovery food during this time is proposed to not only begin the process of post-workout muscle synthesis and refuelling, but do so in an accelerated fashion that has benefits for both body composition and performance. However, research has shown that the importance, and even existence, of such a ‘window’ can vary according to a number of different factors.
The featured benefit of this ‘anabolic window’ is that consuming protein within this period is able to raise your rate of muscle protein synthesis, an important factor when looking to build muscle and strength. However, there is limited research out there to support the claim that an intake of protein and carbohydrates immediately post-workout raises the rate of muscle protein synthesis. Research indicates that it is more important to concentrate on your protein intake across the day rather than in specific time windows.
The second claimed benefit of consuming protein and carbohydrates in this window is to ensure efficient glycogen store replenishment. Glycogen is the form of carbohydrate that is stored in muscle tissue and acts as one of the primary sources of energy, alongside lipids, during a training session. Therefore, after a bout of exercise our bodies glycogen stores are often depleted and will need to be replenished to aid in the recovery process. However, research has shown that consuming carbs immediately after a workout is no more effective for recovery than consuming the same amount of carbohydrate up to 6 hours post-workout. The most important thing is to ensure that your glycogen stores are sufficiently replenished before your next training session.
For elite athletes who may be undertaking multiple training sessions in one day, immediate carbohydrate refuelling may be required. But, for recreational athletes, as long as sufficient carbohydrate is ingested within around 6 hours post-training, no impact has been shown on the rate of muscle glycogen resynthesis.
Essentially, the effectiveness of post-workout fuelling is highly dependent on the individual’s pre-training consumptions. If a significant pre-training meal is consumed 1-2 hours pre-workout, the importance and impact of immediate refuelling 0-1 hours post-workout becomes reduced. This is due to the fact that the pre-training meal can also function as an immediate post-training since the time course of digestion and absorption can stretch well into the post-training recovery period.
Conversely, if exercise is undertaken 4-5 hours after the consumption of a meal, the importance of post-training refuelling becomes enhanced as the body may already well be low in important fuel sources before the training session even began.
Aragon, A. and Schoenfeld, B., 2013. Nutrient timing revisited: is there a post-exercise anabolic window?. Journal of the International Society of Sports Nutrition, 10(1).