What's the first thing that comes to mind after a strenuous workout? If you're thinking about grabbing a protein shake, you're in the right place. For decades, the concept of the "anabolic window" has been prevalent, suggesting that there is a specific 60-90 minute period after exercise when protein consumption is crucial. However, what if the anabolic window is more than just a fleeting timeframe?
Protein Timing:
Contrary to popular belief, protein doesn't vanish after a workout. During physical activity, the body depletes its glycogen stores, and it only starts breaking down muscle tissue after these stores are completely empty. Protein remains available in the body to repair the torn muscle fibers. The process of muscle protein synthesis (MPS) increases during exercise to aid in recovery. A study on the anabolic window revealed surprising results – MPS doesn't decline right after this window; in fact, there appears to be a 12-hour recovery phase (1).
The key to effective recovery lies in maintaining muscle protein synthesis during this extended 12-hour period. The same study demonstrated this by having controlled groups consume 20 grams of whey protein every 3 hours. Remarkably, MPS actually increased over time and peaked at the 4-hour mark (1). Consistently ingesting protein during this timeframe ensures a sustained muscle protein synthesis process.
Larger protein intakes can enhance MPS, but excessive protein consumption can lead to amino acid oxidation (1). Therefore, consuming more than 20 grams of protein at once might not be absorbed efficiently. A practical solution is to align your workout with one of the protein feeding times to optimise digestion and allow protein to fulfill its role during and after the workout.
Protein Around the Clock:
Protein doesn't just work within an arbitrary "anabolic window"; it also operates based on our circadian clock. The concept of the muscle clock, which involves the controlled metabolism of amino acids throughout the day, plays a significant role in protein utilisation. Interestingly, the timing of protein intake may even matter for some individuals.
A study compared individuals who consumed most of their protein in the morning with those who had it during dinner. The group that had a high-protein breakfast showed higher skeletal muscle index and grip strength than the dinner-protein group, even though the total protein intake was similar between the two groups (2).
Post-Workout Protocols:
After a workout, the body shifts into a sympathetic state, characterised by an elevated heart rate, micro-tears in muscle fibers, and reduced glycogen stores. The common assumption is to quickly replenish these with protein and carbohydrates, but rushing may not be the best approach.
During the catabolic state immediately after exercise, the body might not efficiently absorb nutrients. It needs time to switch into a parasympathetic state, which is achieved by lowering the heart rate, to open up the anabolic window. Consuming carbohydrates has a greater impact on heart rate than protein, so including some fast carbs before (or along with) protein can promote a parasympathetic response (3). This primes the body for better absorption of protein.
Is It Myth?
No need to hurriedly down a protein shake at the gym or rush home for a protein fix. The anabolic window is not as narrow as previously thought. Instead, focus on switching into a rest and digest mode after your workout, giving the body ample time to absorb nutrients effectively for optimal recovery.