The effects of pre-sleep consumption of casein protein on next-morning measures of RMR and appetite compared between sedentary pre- and postmenopausal women

Physiological alterations around the menopause transition-A 2-year follow-up in PRE, PERI, and POST menopause females

INTRODUCTION

The menopause transition is a critical period marked by significant physiological adaptations. Data on the dynamic changes in body composition and metabolism during this transition are limited. The purpose was to determine body composition and metabolic changes over a 2-year follow-up in a cross-sectional sample of premenopausal (PRE), perimenopausal (PERI), and postmenopausal (POST) females.

METHODS

Twenty-three females who previously participated in a cross-sectional study returned for a 2-year follow-up visit were classified as PRE, PERI, or POST based on menstrual history and a Menopause Health Questionnaire. Muscle size [muscle cross-sectional area (mCSA)] and muscle quality [echo intensity, (EI)] were evaluated in the vastus lateralis with ultrasound. Bone mass and body composition were assessed using dual-energy X-ray absorptiometry, and metabolic flexibility through submax exercise with indirect calorimetry.

RESULTS

At the 2-year follow-up, POST females had an increase in EI (change: 26.93 ± 12.82 a.u., group×time p-adjusted = 0.001) with no change in mCSA (change: -2.03 ± 2.40 cm², group×time p = 0.980). PERI compared to PRE females had lower total bone mass (group×time p-adjusted = 0.029) with an even lower bone mass in POST compared to PERI females (group×time p-adjusted = 0.023). No differences in metabolic flexibility at any exercise intensity were observed between groups over time (group×time p = ≥ 0.05).

CONCLUSION

This study highlights a decline in muscle quality and total bone mass despite stable muscle size, emphasizing the need for targeted exercise and nutrition interventions to support muscle and bone health in females around the menopause transition.

Sleep Fragmentation and Estradiol Suppression Decrease Fat Oxidation in Premenopausal Women

CONTEXT

Body fat gain associated with menopause has been attributed to estradiol (E2) withdrawal. Hypoestrogenism is unlikely to be the only contributing factor, however.

OBJECTIVE

Given the links between sleep and metabolic health, we examined the effects of an experimental menopausal model of sleep fragmentation on energy metabolism.

METHODS

Twenty premenopausal women (age 21-45 years) underwent a 5-night inpatient study during the mid-to-late follicular phase (estrogenized; n = 20) and the same protocol was repeated in a subset of the participants (n = 9) following leuprolide-induced E2 suppression (hypo-estrogenized). During each 5-night study, there were 2 nights of unfragmented sleep followed by 3 nights of fragmented sleep. Indirect calorimetry was used to assess fasted resting energy expenditure (REE) and substrate oxidation.

RESULTS

Sleep fragmentation in the estrogenized state increased the respiratory exchange ratio (RER) and carbohydrate oxidation while decreasing fat oxidation (all P < 0.01). Similarly, in the hypo-estrogenized state without sleep fragmentation, RER and carbohydrate oxidation increased and fat oxidation decreased (all P < 0.01); addition of sleep fragmentation to the hypo-estrogenized state did not produce further effects beyond that observed for either intervention alone (P < 0.05). There were no effects of either sleep fragmentation or E2 state on REE.

CONCLUSION

Sleep fragmentation and hypoestrogenism each independently alter fasting substrate oxidation in a manner that may contribute to body fat gain. These findings are important for understanding mechanisms underlying propensity to body fat gain in women across the menopause transition.