Introduction
fatigue, SB, sedentary behavior, Fatigue
Fatigue is a complex medical and public health problemValine–proline–proline (VPP) and isoleucine–proline–proline (IPP), collectively referred to as lactotripeptides (LTP), have been isolated from casein milk protein through the proteolytic action of lactic acid and bacteria. LTP has an inhibitory effect on angiotensin-converting enzymes and is safe in cases of overdoseWorld Health Organization guidelines on physical activity (PA) and sedentary behavior (SB) indicate that PA provides significant health benefitsTherefore, this study aimed to investigate the effects of LTP ingestion, PA intervention, and combined intervention on the fatigue status of middle-aged and older adults. We hypothesized that LTP ingestion and PA intervention would provide greater benefits in improving fatigue status than placebo ingestion, LTP ingestion alone, or PA intervention alone.