Perimenopause and Menopause: A Complete Guide to Metabolic Changes and How to Manage Them

Perimenopause is not just about hot flashes and irregular periods—it's a profound metabolic transition that changes how the body processes fats, glucose, and calcium. Understanding these biological changes allows for preventive rather than merely reactive action.

What is Perimenopause and When Does It Start?

Perimenopause is the transitional phase preceding menopause, characterized by irregular periods and increasing hormonal fluctuations. It typically begins around 47 years old (range: 40–55), but can start earlier in cases of premature menopause.

It ends with true menopause: the absence of menstrual periods for 12 consecutive months. In Italy, the average age for menopause is 51.3 years (ISTAT 2024).

Postmenopause is everything that follows—it can last 30–40 years.

Hormonal Changes: What Happens

Menopause is defined by the cessation of ovarian estrogen and progesterone production. But the process is not sudden:

• Estrogen begins to fluctuate erratically during perimenopause, with unpredictable high and low peaks.
• Progesterone decreases first (increasing anovulation).
• Testosterone progressively decreases by 50% between ages 20 and 50 in women (regardless of menopause).
• FSH and LH increase (the brain "asks" the ovaries to produce more estrogen, but the ovaries do not respond).

Metabolic Changes: Why the Body Changes

Estrogens have profound metabolic effects that become evident when they decline:

1. Fat Distribution: From "Pear" to "Apple"

Before menopause, estrogens promote fat distribution in peripheral subcutaneous areas (hips, thighs, buttocks). After menopause, fat redistributes to the abdomen and visceral area—the metabolically most dangerous profile. Visceral fat increases by an average of 25–30% in the first 5 years after menopause, even without changes in total weight.

2. Postmenopausal Insulin Resistance

Estrogens have direct effects on insulin receptors in muscle and adipose tissue. Their reduction significantly increases insulin resistance—independent of increased visceral fat. The risk of type 2 diabetes increases by 40–50% after menopause compared to premenopausal women of the same age.

3. Lipid Profile

Estrogens increase HDL and reduce LDL. After menopause: LDL increases by an average of 10–15 mg/dL, HDL drops by 3–5 mg/dL, triglycerides increase by 10–20%. This transforms many women from "low risk" to "moderate cardiovascular risk" in a few years.

4. Blood Pressure

Estrogens have direct vasodilatory and anti-inflammatory effects on blood vessels. After menopause, blood pressure increases by an average of 5–8 mmHg in 5 years. Women over 60 have a higher prevalence of hypertension than men of the same age.

5. Bone Mass

Estrogens inhibit bone resorption. In perimenopause and the first years of menopause, bone mass loss accelerates: up to 3–5% per year in the first 5 years. The risk of hip fracture increases exponentially after age 65.

6. Muscle Mass

Muscle loss accelerates: women lose about 3% of skeletal muscle mass each year during the first 10 years of postmenopause. Sarcopenia and osteoporosis often coexist—a combination that dramatically increases the risk of falls and fractures.

Epidemiological Data on Italian Women in Perimenopause

• In Italy, approximately 14 million women are in peri- or postmenopause (ISTAT 2024).
• 60–70% of women report significant symptoms during perimenopause.
• The prevalence of hypertension in women doubles between ages 45 and 65.
• The risk of type 2 diabetes in postmenopausal women is 40–50% higher than in premenopausal women.
• 50% of European women over 50 will suffer at least one osteoporotic fracture in their lifetime.

Perimenopause Symptoms: Beyond Hot Flashes

Perimenopause symptoms fall into three categories:

Vasomotor (most well-known)

• Hot flashes: sudden sweating, facial redness
• Night sweats
• Palpitations

Urogenital

• Vaginal dryness, dyspareunia (pain during intercourse)
• Recurrent urinary tract infections
• Mild stress urinary incontinence

Systemic and Metabolic

• Sleep disturbances (difficulty falling asleep, night awakenings)
• Brain fog (difficulty concentrating, short-term memory)
• Mood swings (irritability, anxiety, depressive episodes)
• Weight gain without changes in diet
• Joint pain (arthralgia due to estrogen decline)
• Dry skin

What to Actively Monitor in Perimenopause

Blood Pressure

With reduced estrogen, blood pressure tends to increase. Weekly home monitoring allows for early detection of potential hypertension. The Pulse 3 also detects arrhythmias—relevant in this phase because menopausal palpitations can be difficult to distinguish from real arrhythmias.

Blood Glucose and Glucose Metabolism

With increased postmenopausal insulin resistance, fasting and postprandial blood glucose deserve attention. The G1 Pro allows monitoring of glycemic response to meals and early detection of a transition to pre-diabetes—often silent.

Body Composition

Weight alone does not reveal the redistribution of fat to the visceral area. The Brio 1 Pro measures visceral fat, muscle mass, and body water—the parameters that change most significantly in perimenopause.

Hormone Replacement Therapy (HRT): Pros, Cons, and Who Can Use It

Hormone Replacement Therapy (HRT) remains the most effective treatment for severe vasomotor symptoms of menopause. The ESE 2024 guidelines recommend it for symptomatic women without contraindications, initiated within age 60 or within 10 years of menopause ("therapeutic window").

• Documented benefits: >80% reduction in hot flashes, improved sleep quality, bone protection, reduced cardiovascular risk if started within the therapeutic window.
• Risks: slight increase in breast cancer risk with estrogen-progestin combination for >5 years (not with estrogen alone in hysterectomized women); thromboembolic risk with oral formulations.
• Absolute contraindications: active breast cancer, recent history of deep vein thrombosis, severe liver disease.

HRT is not for everyone, but it should not be ruled out a priori due to fear—individual risk/benefit assessment with a gynecologist is the correct approach.

Lifestyle in Perimenopause: The 5 Priorities

1. Resistance training: 2–3 sessions/week are the most effective measure against sarcopenia and osteoporosis at this stage.
2. Adequate protein: 1.2–1.5 g/kg/day to preserve muscle mass.
3. Calcium and vitamin D: 1000–1200 mg/day of calcium (from food, not just supplements) + vitamin D3 2000 IU/day.
4. Low-GI diet: to counteract increasing insulin resistance.
5. Active monitoring: blood pressure, blood glucose, body composition—don't wait until numbers are out of range.

Frequently Asked Questions

Can perimenopause start at age 40?

Yes. "Premature ovarian insufficiency" (POI) affects 1% of women under 40. "Normal" perimenopause can begin between ages 40 and 45. Irregular cycles in this age group warrant hormonal evaluation (FSH, estradiol, AMH).

Is weight gain inevitable during menopause?

The average weight gain during menopause is 2–5 kg in 5 years—and it is not inevitable. The inevitable part is the redistribution of fat towards the abdomen, even without weight variation. With resistance training and an appropriate diet, both weight and body composition can be actively managed.