High-intensity interval exercise is more efficient than medium intensity exercise at inducing neurogenesis

Area of Science:

• Neuroscience
• Exercise Physiology
• Aging Research

Background:

• Brain aging diminishes neurogenesis, increasing susceptibility to neurodegenerative diseases and stroke.
• Adult neurogenesis occurs in the subgranular zone (SGZ) and ventricular-subventricular zone (V-SVZ).
• Exercise is known to enhance SGZ neurogenesis, and V-SVZ neurogenesis is linked to the lactate receptor HCA₁.

Purpose of the Study:

• To investigate the differential effects of high-intensity interval training (HIIT) and medium-intensity interval training (MIIT) on neurogenesis in the SGZ and V-SVZ.
• To determine the role of the HCA₁ receptor in exercise-induced neurogenesis in these niches.

Main Methods:

• Wild-type (WT) and HCA₁ knockout (KO) mice were subjected to sedentary, HIIT, or MIIT protocols for 3 weeks.
• Neurogenesis was assessed by quantifying doublecortin (DCX)-positive and Ki-67-positive cells in the SGZ and V-SVZ.

Main Results:

• HIIT significantly increased DCX-positive cells in the SGZ of both WT and KO mice, while MIIT had no effect.
• In the V-SVZ, both HIIT and MIIT robustly increased DCX-positive cells in WT mice, but not in KO mice.
• HIIT demonstrated a more pronounced effect on neurogenesis in both niches compared to MIIT.

Conclusions:

• HIIT is a more potent stimulus for neurogenesis in both the SGZ and V-SVZ than MIIT.
• HCA₁ receptor activation is critical for exercise-induced neurogenesis in the V-SVZ.
• Neurogenesis regulation differs between the SGZ and V-SVZ in response to exercise intensity and receptor activation.