Age-Related Differences in the Appetite-Regulating Hormone Response to Exercise.

Area of Science:

• Exercise physiology
• Endocrinology
• Gerontology

Background:

• Acute exercise influences appetite-regulating hormones, including peptide tyrosine tyrosine (PYY), glucagon-like peptide-1 (GLP-1), and ghrelin, affecting appetite and food intake.
• While exercise effects on hunger and satiety are known to vary by body composition, sex, and physical activity, the impact of aging remains less understood.

Purpose of the Study:

• To investigate age-related differences in the response of appetite-regulating hormones to acute exercise.
• To compare the effects of moderate-intensity exercise on PYY, GLP-1, and ghrelin levels between younger and older adults.

Main Methods:

• Two age cohorts (younger adults: 19-29 years; older adults: 65-75 years) participated in randomized exercise and rest conditions.
• Participants underwent 45-minute cycling exercise (60% V̇O2peak) or seated rest, with blood samples collected for hormone analysis (PYY3-36, GLP-1, acylated ghrelin) and subjective appetite ratings.

Main Results:

• Exercise increased PYY3-36 more in younger adults than older adults (P=0.025).
• GLP-1 levels were higher in older adults overall, but the exercise-induced GLP-1 response did not differ by age.
• Exercise responses for acylated ghrelin and subjective appetite perceptions showed no significant age-related differences.

Conclusions:

• Acute moderate-intensity exercise elicits age-related differences in PYY3-36 response, but not in GLP-1 or acylated ghrelin.
• These hormonal variations did not lead to significant differences in perceived hunger or fullness between younger and older adults.