Effect of swallowing related fatigue on eating and drinking behaviors across the age spectrum

Background. Swallowing related fatigue refers to the decline in swallowing efficiency and safety due to sustained muscular effort over time. It can significantly impact eating and drinking behaviors, potentially leading to aspiration, malnutrition and diminished quality of life. Understanding the effects of swallowing fatigue across the age spectrum can help guide clinical interventions and management strategies. Hence, this study aims to evaluate the effects of swallowing-related fatigue on eating and drinking behaviors in young, middle-aged and older adults. Methods. A cross-sectional study was conducted, recruiting 400 healthy individuals divided into three groups consisting of young adults, middle-aged adults and older adults. Participants with speech, language, swallowing, neurological, or cognitive impairments were excluded. The study utilized standardized assessments, including the Swallowing and Eating-Related Fatigue Scale (SERF) to measure swallowing fatigue. Objective swallowing function was evaluated using the Timed Water Swallow Test (TWST) for liquid intake, the Test of Masticating and Swallowing Solids (TOMASS) for solid food consumption, and the Mealtime Assessment Scale (MAS) to assess overall mealtime behaviors. Video recordings of swallowing tasks were analyzed to measure efficiency, speed, and fatigue-related changes. Results. Swallowing fatigue was significantly higher in older adults compared to middle-aged and young adults. TWST results showed that older adults exhibited longer swallowing durations, smaller bolus volumes per swallow, and reduced swallowing efficiency, though correlations between TWST parameters and fatigue were weak. In contrast, TOMASS scores revealed moderate associations with swallowing fatigue, as older adults took more bites, had longer mastication durations, and required more swallows per bolus. MAS scores demonstrated moderate to strong correlations with swallowing fatigue across all age groups, indicating that individuals experiencing higher fatigue levels displayed compromised mealtime efficiency and safety. Reliability analyses confirmed excellent test-retest reliability for TWST & TOMASS, with good to excellent interrater reliability. Conclusion. This study underscores the impact of swallowing-related fatigue on eating and drinking behaviors, particularly among older adults. While swallowing fatigue had minimal to moderate influence on TWST and TOMASS parameters respectively, MAS demonstrated stronger associations, suggesting that swallowing endurance plays a critical role in overall mealtime performance. These findings highlight the importance of integrating fatigue assessments into clinical dysphagia evaluations, as fatigue-related impairments may increase the risk of nutritional deficits and aspiration. Future research should focus on developing interventions to mitigate swallowing fatigue and improve mealtime efficiency, particularly in aging & clinical populations.