High-intensity interval training in aged female mice preserves physical, cognitive, and cardiovascular function

With advancing age comes declines in physical, cognitive, and cardiovascular function, leading to decreased performance in activities of daily living and eventual loss of independence. Exercise may delay this decline. High-intensity interval training (HIIT) consists of intense activity periods interspersed with bouts of active recovery. Previously, we demonstrated that HIIT preserved physical function in male mice across the lifespan. In the current work, we extend our prior investigations to include females and add a multitude of assessments previously unstudied. We hypothesized that cognitive, physical, and cardiovascular function/health would be preserved in exercised mice (HIIT) versus sedentary controls (SED). C57BL/6J mice (randomized to HIIT and SED, both n = 9, 24 months old at end) were tested pre/post-intervention for physical, cognitive, and cardiovascular function, body composition, whole body calorimetry, and post-intervention by various markers of health using immunohistochemistry. The HIIT mice underwent 14-weeks of training with progressive volume and intensity. HIIT significantly (p < 0.05) preserved function in many areas: aerobic capacity (+ 71% HIIT, no change, NC, in SED), four limb strength/endurance (-67% SED, -28% HIIT), forelimb strength (-16% SED, NC HIIT), overall motor function (NC SED, + 39% HIIT), executive function (NC SED, + 73% HIIT), and exploratory behavior (improved across multiple tests). HIIT lowered systolic blood pressure (-17 mmHg, -12%) and mean arterial pressure (-16 mmHg). HIIT reduced cardiac fibrosis, reduced IL-1β expression in the hippocampus, and mitigated frailty onset. In conclusion, HIIT reduced age-related functional loss, prevented frailty, and improved markers of brain/heart health, providing further support for HIIT as an anti-aging therapy.