Examining the obesity paradox: A moderating effect of fitness on adipose endocrine function in older adults.

Despite evidence linking obesity with increased mortality, older adults with excessive adiposity seem protected, resulting in a so-called obesity paradox. Obesity is characterized by leptin resistance, which contributes to increased risk of all-cause mortality. Therefore, lifestyle factors, such as physical fitness, that lower leptin independent of adiposity may be confounding the obesity paradox. To investigate this, we evaluated whether physical fitness moderated the relationship between leptin and adiposity. We found older adults with higher fitness had lower body mass (r(39) = -0.43, p < 0.01), leptin (r(39) = -0.29, p = 0.03) and inflammation (IL-1ß: (r(39) = -0.69, p < 0.01); TNF-α: (r(39) = -0.30, p = 0.03)). Fitness moderated the relationship between leptin and adiposity (F(5, 37) = 3.73, p < 0.01, R2 = 0.33) to reveal the obesity paradox in moderately and high fit individuals (b = 216.24, t(37) = 1.46, p = 0.15; b= -88.10, t(37) = -0.49, p = 0.63) but not in low fit individuals. These results show the link between obesity and mortality may not be dependent on total adiposity, but rather on endocrine function and adipocyte leptin secretion. These results have important implications for older adults struggling to maintain healthy body composition and suggest that fitness may promote overall wellbeing.

Examining a training effect on the state anxiety response to an acute bout of exercise in low and high anxious individuals.

BACKGROUND: An acute bout of exercise temporarily reduces state anxiety. The current study examined whether these benefits are greater for those with higher levels of anxiety, and whether these benefits are augmented with exercise training. METHODS: Young adults were randomized to either a nine-week moderate-intensity exercise group or an inactive control group. We assessed changes in state anxiety in response to an acute bout of exercise each week. RESULTS: State anxiety reductions following acute exercise increased in the exercise subgroup with high anxiety at baseline as training progressed (p = .029). No training effects were observed for the exercise subgroup with low baseline anxiety (p = .27). LIMITATIONS: A predominantly female sample, a single state anxiety measure post exercise and a non-exercise control group should be addressed in future research. CONCLUSIONS: The results support the use of regular physical activity as a method for managing state anxiety in young adults. In particular, regular physical activity may be especially beneficial for those experiencing higher levels of anxiety.