SLEEP LOSS RESULTS IN A REDUCTION IN MUSCLE PROTEIN SYNTHESIS . SLEEP LOSS COMBINED WITH HIIT INCREASES PROTEIN SYNTHESIS TO THE SAME AS NORMAL SLEEP WITHOUT EXERCISE . SLEEP LOSS CAN CAUSE A DECREASE IN MUSCLE MASS
MUSCLE PROTEIN SYNTHESIS DURING SLEEP KEY POINTS:
- MUSCLE PROTEIN SYNTHESIS DURING SLEEP WAS REDUCED WITH SLEEP DEPRIVATION
- SLEEP LOSS COMBINED WITH HIIT INCREASES PROTEIN SYNTHESIS TO THE SAME AS NORMAL SLEEP WITHOUT EXERCISE
- SLEEP LOSS CAN CAUSE A DECREASE IN MUSCLE MASS
MUSCLE PROTEIN SYNTHESIS DURING SLEEP
When discussing muscle growth, the conversation often revolves around dietary protein intake, training volume, intensity, and consistency. However, an often-underestimated component of this equation is sleep. Sleep isn’t just about feeling rested; it’s a fundamental pillar for overall health, cognitive function, and, importantly, muscle recovery and growth.
Sleep is a restorative process that affects nearly every system in our body, from the brain to the muscles. The recommended sleep duration for adults ranges between 7 and 9 hours per night.(1) This isn’t just about feeling alert the next day; it’s about giving the body the time it needs to repair, regenerate, and grow.
If a person is dieting, a larger loss of lean muscle mass has been reported in subjects who slept 5.5 hours a night compared to those sleeping 8.5 hours a night.(3) One theory why not getting enough sleep can cause loss of lean muscle is a previous study found that 72 hours of sleep deprivation caused an increase in cortisol and protein breakdown (4).
Researchers wanted to investigate if sleep loss combined with high-intensity interval training would affect muscle protein synthesis. HIIT has been found to stimulate muscle growth when subjects are well-rested, but the responses of HIIT and sleep loss have yet to be investigated.
HIIT AND SLEEP LOSS
Researchers examined muscle protein synthesis in response to adequate sleep, Sleep loss, and Sleep loss combined with HIIT. The sleep loss group was allowed 4 hours of sleep a night for 5 nights. The HIIT protocol had subjects cycle at 90% of each participant’s peak oxygen capacity combined with 10 intervals for 60-seconds with 75 seconds rest between exercise intervals.
At the end of the study, 5 nights of sleep restriction resulted in dramatically lower muscle protein synthesis rates. Interestingly, the sleep loss combined with HIIT resulted in no further increases in protein synthesis compared to the group without exercise, who slept normally for 8 hours. HIIT results in an increase in muscle protein synthesis compared to those not exercising but sleep restriction, and HIIT results in the same increases in muscle protein synthesis as those not exercising.
This suggests that not getting enough sleep will have a major reduction in muscle protein synthesis compared to sleeping for 8 hours and training hard. The increases in muscle protein synthesis were normal sleep, no exercise = similar increases in muscle protein synthesis as HIIT plus sleep restriction. Sleep restriction resulted in a 19% lower increase in muscle protein synthesis compared to normal sleep and HIIT plus sleep restriction. (5)