Pre-sleep consumption of 40 grams of whey protein or a rice-pea plant-based protein blend has no significant effect on muscle recovery in middle-aged men following damaging morning eccentric exercise, as measured by isometric and isokinetic strength, muscle soreness, and biomarkers of muscle damage over 72 hours.

After intense muscle damage, the body needs protein quickly to start repairing torn muscle fibers, but drinking protein before sleep delays its absorption until deep into the night, missing the critical window when muscle repair is most active. The muscles are still breaking down and inflamed during the first 24 to 48 hours, and the protein doesn't arrive in time to stop the loss of strength or reduce soreness.