Maastricht University researchers point to a combination of increased dietary protein, ingestion prior to sleep and type of exercise as reasons for the gains in muscle growth and performance.
However, they held back on which factor had the edge commenting, “Whether this beneficial effect on pre-sleep protein ingestion on muscle mass and strength gain during resistance-type exercise training are due to an increased total protein intake rather than by its specific timing remains elusive, and warrants further research.
As well as athletes, the review’s findings may have relevance to older populations, where pre-sleep protein’s combination with exercise may improve overnight muscle protein distribution.
Resistance exercise pluses
Experts universally recognise resistance-type exercise training as effective in increasing skeletal muscle mass and strength.
This type of exercise also dictates muscle protein synthesis as well as breakdown rates, although these rates are stimulated to a lesser extent.
The muscle protein synthetic response following exercise is modifiable to the type, amount, distribution, and timing of protein ingestion.
Timing in particular is a topic of much debate with protein ingestion prior to sleep as an additional meal moment could further maximize the skeletal muscle adaptive response.
Caesin is also deemed the better protein type for overnight nutrition as it is a slow-release protein that is absorbed at a different rate when compared to faster acting whey protein.
The review includes several studies that show pre-sleep protein intake overnight increases muscle protein synthesis during overnight sleep in young adults.
According to lead author Dr Tim Snijders, assistant professor at Maastricht University, the studies have “fuelled the idea that over a longer period, a pre-sleep protein supplement can maximize the strength and muscle mass gains during regular resistance exercise training”.
One study of note placed 44 healthy young men on a 12-week lifting program. Half consumed a nightly pre-sleep protein shake with about 30 grams (g) of casein and 15 grams of carbs, while the other half drank an energy-free drink.
Consistent resistance training resulted in both groups ending with a bigger squat (one rep max) and bigger quad muscles.
However, the protein-before-bed group gained significantly more muscle strength and size.
Sleep and muscle growth
The role of sleep was also taken into consideration as a factor in muscle recovery and growth with the idea that an intake of protein just before bed could see protein intake distribution improve over 24 hours.
"A survey of over 500 athletes found they were typically consuming at total of more than 1.2g protein per kilo of bodyweight across three main meals, but only a paltry 7g of protein as an evening snack,” said Dr Snijders.
“As a result, lower levels of amino acids would be available for muscle growth during overnight sleep."
The team summed up by saying that protein ingestion before sleep appeared to be effectively digested and absorbed during sleep.
This increased plasma amino acid availability, stimulating muscle protein synthesis during overnight sleep in both young and old.
“When pre-sleep protein intake is combined with exercise performed the same evening, overnight muscle protein synthesis rates will be further increased,” the review added.
“Protein ingestion prior to sleep can be applied in combination with resistance type exercise training to further augment the gains in muscle mass and strength when compared to no protein supplementation.
Source: Frontiers in Nutrition
Published online: doi.org/10.3389/fnut.2019.00017
“The Impact of Pre-sleep Protein Ingestion on the Skeletal Muscle Adaptive Response to Exercise in Humans: An Update.”
Authors: Tim Snijders, Jorn Trommelen, Imre Kouw, Andrew Holwerda, Lex Verdijk and Luc van Loon.