The Timing of Nutrition
For athletes looking to maximise the benefits of this drastically increased positive protein balance, timing is important. A study testing when amino acid intake should occur showed unequivocally that greater gains in strength and muscle size were seen when amino acid consumption was timed to coincide with resistance exercise rather than spaced over the day, and other studies indicate that nutrient timing can aid recovery.
Various studies have shown that levels of MPS rise rapidly after exercise or competition and, if amino acids are provided through consuming protein sources such as whey and soy, the rate of MPS peaks at around 3-4 hours. From this point it gradually declines, yet elevated MPS is still observable up to 48 hours after exercise.
Delays to appropriate amino acid intake can have a negative effect on MPS and therefore an impact on recovery and strength. If resistance exercise or high-intensity sport is carried out in a fasted state, whilst the rates of both MPS and MPB increase, the resulting protein balance remains approximately neutral or even negative. In one study, those delaying nutrition for only two hours post exercise lost muscle mass as a result.
Any loss of muscle mass due to sub-optimal nutritional planning can impact on an athlete’s ability to recover. In today’s sporting environment, success at many levels can hang on the finest margins. This is why achieving maximum potential from the MPS window is essential.
Numerous studies indicate that MPS potential is highest immediately after exercise or competition, referring to it as “the window of anabolic potential” or “the 30 minute window”. As this window opens immediately after exercise and wanes over time, it is imperative that readily available amino acids reach the blood as rapidly as possible. It is for this reason that protein consumption timing is so important for achieving maximum gains and plays such a big role in sports nutrition.
Following a short lag phase after exercise, the rates of MPS begin to spike, peaking after about three hours before steadily declining over the next 24-48 hours.
The height of this spike and, therefore, the maximum rate of MPS depends on the speed with which amino acids can be delivered.
It has been suggested that the early peak in the window of anabolic recovery may be due to a combination of two factors; the reactivation of mTOR combined with the increased blood flow in the muscles, together creating the optimum recovery environment for the muscle cells.
During exercise, there is a dramatic increase in the blood flow to the muscles to provide oxygen and energy, with blood flow up to 64 times greater than normal. Following exercise, this blood flow remains elevated, gradually declining but remaining above resting level for around one hour. It is this increased blood volume that may aid recovery and, as such, offers the optimum environment for the hyperacidaemia required for maximum MPS. One study has reported that these conditions led to an increase in amino acid transport into the muscles of between 30-100% during this period.