Metabolic Effects of Perimenopause

Study Summary

Starting in early-perimenopause, changes in systemic and tissue level metabolism result in an accelerated loss of muscle mass and an increase in body fat. Our preliminary work indicates that metabolic alterations, specifically a decrease in whole-body protein balance, increase in abdominal adiposity, and reduced metabolic flexibility during exercise is most evident in perimenopause. Exercise is a potent stimulator of skeletal muscle insulin sensitivity. High intensity interval training (HIIT) has been shown to be an effective exercise strategy to support cardiometabolic health in overweight and obese young women. Skeletal muscle is critical to maintaining metabolic health and functionality across the lifespan, and is considered the primary diver of whole-body insulin resistance.There is a significant decrease in muscle mass across the menopause transition, which is often exacerbated by a significant gain in fat mass and visceral fat. Protein consumption prior to HIIT has resulted in improvements in energy expenditure and fat oxidation in young women. The overarching objective of this study is to determine the metabolic response of HIIT compared to traditional aerobic exercise in early and late perimenopausal women. Aim 1 will examine the metabolic responses (glucose, insulin sensitivity, energy expenditure) of HIIT vs aerobic exercise, combined with pre-exercise carbohydrate or protein ingestion, in overweight/obese (BMI: 28-40 Kg/m\^2) early and late perimenopausal women. Aim 2 will explore the impact of perimenopause on the fat oxidation and protein turnover before and after exercise. Lastly, aim 3 will explore the modulating effect of intramuscular fat on these metabolic outcomes.

Primary Outcome

Indirect calorimetry will be used to obtain energy expenditure prior to exercise and 30 minutes after a bout of high intensity interval training.

Interventions

• OTHER Whey Protein Isolate
• OTHER Non-caloric Placebo water