Arnold Schwarzenegger believes a full night’s sleep is essential for reaching your fitness goals. In his July 17 Arnold’s Pump Club newsletter, he broke down why protein works less efficiently for building muscle when you don’t get enough sleep.
“Why Protein Works Less When You Don’t Sleep – You know the week: A deadline, a sick kid, a flight that got moved. Life gets chaotic, so something has to give. You still train. You still eat well and hit your protein. But sleep is the thing you decide to pay back later because it feels like the cheapest bill on the table.”
During the Golden Era of bodybuilding, Arnold Schwarzenegger cemented himself as an all-time great. En route to winning seven Mr. Olympia titles, he defeated legendary Men’s Open competitors, including Sergio Oliva and Lou Ferrigno.
In retirement, Schwarzenegger has made changes to his diet, training, and recovery. Though we often hear about protein intake and training for muscle growth, Schwarzenegger also explains why sleep can make or break your muscle-building goals.
Arnold Schwarzenegger Warns Sleep Loss Can Reduce Muscle-Building Response to Protein by Nearly 20%
In the newsletter, Schwarzenegger pointed to a study that examined young adults in a sleep lab.
“Scientists found that when you don’t get enough sleep, your body might have a harder time building muscle. Researchers studied young adults in a sleep lab and tested different sleep scenarios, ranging from 8 hours to just 4 hours. Everyone ate the same food, portioned by body weight, with a specific focus on getting enough protein to support recovery and muscle growth.”
He shared that those who slept only 4 hours per night built new muscle protein nearly 20 percent more slowly than those who slept normally.
“Those who slept only 4 hours per night built new muscle protein 19% slower than men who slept normally. And it wasn’t just that study. In a different lab, using a different method, scientists asked how your muscles react to the food you give them after a night of no sleep at all. Much like the other study, muscles responded 18 percent less when sleep-deprived.”
According to the bodybuilding legend, this is called anabolic resistance, and it can occur more often when we don’t get enough sleep.
“This is what scientists call anabolic resistance. The protein reaches your muscles, but the machinery that helps you build and recover responds less.”
He also cited a separate study showing that people who slept 5.5 hours lost 60 percent more lean mass despite following a similar diet to those who slept for eight hours.
“And in another study, when researchers compared 5.5 hours of sleep to 8.5 hours in people who were cutting calories, the sleep-deprived participants lost 60% more lean mass, despite being on the same diet and seeing the same overall weight loss. In other words, sleep deprivation led to greater muscle loss and less overall fat loss.”
For better sleep, Schwarzenegger recommended a cooler room and eliminating screen time before bed.
“The lesson: don’t view sleep as competing with training or diet. They all work together. And the more you sacrifice sleep, the more your body starts to work against you. The standard fix — wind-down routine, cooler room, screens off at least an hour before bed — all can make a real difference. But for some people, getting better rest still feels like a tall task.”
Your protein response isn’t the only thing suffering when you miss out on sleep. The seven-time Mr. Olympia recently explained how poor sleep impacts strength and endurance, which can make your workouts feel more difficult.
Schwarzenegger contends that training, diet, and sleep all work in unison. He believes prioritizing a few extra hours of sleep per night will pay off in the long run.
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