Better Sleep May Help You Stay Strong as You Age—If Your Diet Backs It Up.

A 2025 study in Nutrients found that adults who slept longer and had better sleep quality also had stronger handgrip strength—but only when they consumed more protein and followed a higher-quality diet.

Researchers analyzed data from over 1,300 middle-aged adults and discovered that protein intake (grams per kilogram of body weight) and overall diet quality, measured by the Healthy Eating Index, played a key role in linking sleep to muscle strength. Physical activity, however, did not significantly mediate this relationship. This suggests that adequate sleep may help preserve muscle strength as we age, but only when paired with sufficient protein and a nutrient-rich diet.

To support muscle health, prioritize sleep and include high-quality protein sources like eggs, beef, and fish in your meals.