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Updated: Jun 9, 2025

A Chronic High-Intensity Interval Training and Diet-Induced Obesity Model to Maximize Exercise Effort and Induce Physiologic Changes in Rats
Published on: April 28, 2023
Subacute Effects of Moderate-Intensity Aerobic Exercise in the Fasted State on Cell Metabolism and Signaling in
Layane Ramos Ayres1,2, Éverton Lopes Vogt3, Helena Trevisan Schroeder1
1Laboratório de Inflamação, Metabolismo e Exercício (LAPIMEX) e Laboratório de Fisiologia Celular, Departamento de Fisiologia, Instituto de Ciências Básicas da Saúde, Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre 90035-003, RS, Brazil.
Abstract:
Background: Physical inactivity induces insulin resistance (IR) and metabolic imbalances before any significant changes in adiposity. Recent studies suggest that the beneficial effects of exercise can be potentiated if performed while fasting. This work aimed to compare the subacute effects of fed- and fasted-state single-bout exercise on biochemical parameters and cellular signaling in the metabolism. Methods: The animals were allocated into fed rest (FER), fasting rest (FAR), fed exercise (FEE), and fasting exercise (FAE) groups. The exercise protocol was a 30 min treadmill session at 60% of V˙O2max. The fasting groups fasted for 8 h before exercise and were killed after 12 h post-exercise. Results: Soleus glycogen concentration increased only in the fasting groups, whereas the triglyceride (TGL) content increased in brown adipose tissue (BAT) and liver in the FAE. The FAE showed decreased plasma total cholesterol concentration compared withthe FAR group. Immunocontent of HSP70, SIRT1, UCP-1, and PGC1-α did not change in any tissue investigated. Conclusions: Our results indicate that physical exercise while fasting can have beneficial metabolic effects on sedentary animals. Remarkably, in the FAE group, there was a reduction in total plasma cholesterol and an increase in the capacity of BAT to metabolize and store nutrients in the form of TGLs.
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