The Menopausal Transition

The Physiological Impact of the Menopausal Transition: A Clinical Perspective

The transition into menopause, specifically the perimenopausal years, represents a significant biological shift driven by a natural decline in primordial follicles over the lifespan. This period is characterised by a decrease in estrogen and progesterone, which triggers systemic changes across multiple body systems, including the cardiovascular, metabolic, musculoskeletal, and cognitive systems.

As an exercise physiologist, understanding these physiological shifts is essential for developing effective strategies to manage health and physical function during this time.

Chronology of the Transition

Natural menopause typically occurs between the ages of 45 and 55, with the average age being 51. If it occurs between 40 and 45, it is clinically considered "early". The process is generally categorised into two primary phases:

Phase 1: Perimenopause

This phase consists of the years preceding menopause, typically lasting 4 to 6 years, though it can extend to 10 years. It is often identified by:

• Hormonal Volatility: Erratic peaks in estrogen and inconsistent luteal phase levels of progesterone.

• Cycle Irregularity: "Variable length" cycles, defined by at least a 7-day difference between consecutive cycles, or cycles shorter than 25 days or longer than 35 days.

• Symptom Progression: Early perimenopause is often associated with high estrogen symptoms like heavy periods and breast tenderness. Late transition typically shifts toward low estrogen symptoms, including vasomotor symptoms (hot flashes, night sweats), vaginal dryness, and muscle weakness.

Phase 2: Menopause

Menopause is a specific point in time, defined as exactly 12 months after the final menstrual period. Following this milestone, symptoms related to estrogen deficiency, particularly vasomotor symptoms, remain common.

Key Physiological Consequences

The decline in ovarian hormones has several documented effects on long-term health that require proactive management:

·       Cardiovascular Health: There is an increased risk of cardiovascular disease, including atherosclerosis and endothelial dysfunction. Post menopausal women have 3.4 times greater risk of atherosclerosis compared with premenopausal women.

·       Metabolic Health: Many individuals experience increased insulin resistance, estrogen suppression has been shown to result in insulin resistance and Type 2 Diabetes.  

·       Body Composition changes: The accumulation of visceral fat and the loss of lean mass. Typically, there is a loss of lean muscle mass with a 1-3% increase in weight. Visceral fat increases from 5-8% of total body fat in the premenopausal state to 15-20% of total body fat in the post-menopausal state. Loss of muscle mass- 0.5%-1% reduction in muscle mass due to menopausal transition.

·       Musculoskeletal Health: A primary concern is the loss of bone mineral density, alongside a decrease in muscle mass and strength. Joint pain and myalgia are also frequently reported during this transition. Can start in peri-menopause and continue for 5-8 years. Typical loss is between 1-2% per year but is often much higher at 3-5% annually.

• Cognitive & Systemic Symptoms: Vasomotor symptoms affect 60–80% of women for an average of 7.5 years. Cognitive changes, such as "brain fog," mood disturbances, and sleep difficulties like insomnia, are also prevalent.

The role of exercise and physical activity:

·       Increased cardiorespiratory fitness

·       Improved apolipoprotein profile- a reduction in the risk of developing cardiovascular diseases

·       Retention of muscle mass

·       Reduced visceral fat

·       Improved insulin sensitivity

·       Improved sleep

·       Improved mental health and quality of life

·       Improved bone mineral density

Exercise Physiology Approach to Management

To address these systemic shifts, exercise programming must evolve beyond general fitness to focus on targeted physiological outcomes:

1. Prioritise Structural Integrity: Addressing the loss of bone density and lean muscle mass through progressive resistance training is vital.

2. Incorporate High-Intensity Intervals: Modes such as High-Intensity Interval Training (HIIT) and Sprint Interval Training (SIT) are important tools for metabolic and cardiovascular health.

3. Mechanical Loading: Incorporating impact exercises can further support bone health.

4. Symptom-Informed Programming: To ensure a plan is sustainable, it should account for secondary symptoms such as fatigue, joint pain, and pelvic health issues like an overactive bladder or continence concerns.

At Advanced Health Exercise Physiology we can create an individualised exercise program focused on mitigating the loss of lean muscle mass and bone mineral density mentioned in these findings.

References:

1.     Elder et al. 2020

2.     https://www.monash.edu/medicine/sphpm/womenshealth/research

3.     Ambikairajah et al. 2019; Greendale et al. 2019; Juppi et al., 2022l Loyjoy et al., 2020

4.     Maki et al., 2019

5.     Eastell et al. 2016