Hourly assessments of single-item immune fitness demonstrate its consistency during the day
Immune fitness is the body’s capacity to respond to health challenges (such as infections) by activating an appropriate immune response. Adequate immune fitness is crucial to maintaining health and preventing and resolving disease. Control day data from an experimental study among 29 healthy volunteers were evaluated to determine the consistency of immune fitness ratings throughout the day. The single-item immune fitness scale was completed hourly, from 09:30 to 15:30. As a comparison, mood was assessed with the Profiles of Mood States-Short Form, including subscales for vigor, fatigue, tension, depression, and anger. The analyses revealed that single-item immune fitness scores were stable throughout the day. In contrast, as expected, assessments of fatigue and vigor varied throughout the day, showing more energy in the morning assessments and less energy in the afternoon assessments. Tension, depression, and anger scores also remained stable throughout the day. In conclusion, this study demonstrates that single-item immune fitness ratings remain consistent and stable throughout the day. Therefore, the time of day at which participants assess their immune fitness does not influence the outcomes in clinical trials. Future studies in larger, more diverse samples can be conducted to confirm these findings.
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