What causes a perimenopausal or menopausal woman to experience body temperature dysregulation, fluctuating between feeling too hot or too cold?

Body Temperature Dysregulation in Perimenopausal and Menopausal Women

Primary Cause

The fluctuating body temperatures experienced by perimenopausal and menopausal women are primarily caused by hormonal changes—specifically estrogen fluctuations and deficiency—that disrupt hypothalamic thermoregulatory control, narrowing the thermoneutral zone and triggering inappropriate heat loss responses. 1, 2, 3

Underlying Mechanisms

Hormonal and Neural Pathways

• Estrogen fluctuations during perimenopause and menopause alter the hypothalamic thermoregulatory center, causing it to become hypersensitive to minor elevations in core body temperature 2, 4, 3

• The thermoneutral zone (TNZ) becomes narrowed, meaning the range of core body temperatures that can be tolerated without triggering heat loss or heat conservation mechanisms becomes extremely small 4, 3

• KNDy neurons (kisspeptin-neurokinin B-dynorphin) in the arcuate nucleus become hyperactive when estradiol levels decrease, and these neurons project to thermoregulatory areas in the hypothalamic preoptic area, triggering cutaneous vasodilation and sweating 2, 3

• Additional neurotransmitters involved include calcitonin gene-related peptide, serotonin, and norepinephrine, all of which contribute to the dysregulated temperature control 2

Physiological Response Pattern

• During a hot flash, mean core body temperature increases by only 0.5°C, while skin temperature rises 0.25-3°C, demonstrating that the response is disproportionate to actual temperature changes 4

• Hot flashes manifest as transient sensations of heat, sweating, flushing, anxiety, and chills lasting 1-5 minutes 2

• The "feeling cold" phase often follows the hot flash as an overcorrection, representing the body's attempt to restore thermal equilibrium after inappropriate heat dissipation 3

Specific Causes in Menopausal Women

Natural Menopause

• Perimenopause and menopause represent the most common cause, with 50-85% of women over age 45 experiencing vasomotor symptoms 1, 5, 4

• Hot flashes affect most women, with approximately one-third experiencing moderately to severely problematic symptoms 5

• Duration varies significantly: most women experience symptoms for 1-2 years, but others suffer for a decade or more, and some never achieve complete resolution 5

Cancer Treatment-Related Causes

• Endocrine therapies for breast cancer (tamoxifen and aromatase inhibitors) are significant triggers 6, 1, 7

• Tamoxifen causes less vaginal dryness (8%) compared to aromatase inhibitors (18%), but both can trigger severe vasomotor symptoms 6

• Chemotherapy-induced ovarian dysfunction causes temporary or permanent menopause in younger women 6, 7

• Bilateral oophorectomy results in hot flashes in >90% of women, with symptoms being particularly severe and long-lasting 6

Medication-Related Causes

• Discontinuation of hormone replacement therapy commonly produces recurrence or worsening of menopausal symptoms 6, 1

• Dopamine-reuptake inhibitors and certain diuretics can trigger hot flashes 7

Exacerbating Factors

Dietary and Environmental Triggers

• Spicy foods, alcohol, and caffeine can trigger or worsen hot flashes 1, 7

• Hot environments, hairdryers, and overheating precipitate episodes 1, 7

Lifestyle Factors

• Smoking is associated with more severe hot flashes 1, 8

• Obesity correlates with increased severity of vasomotor symptoms 1

• Stress and anxiety can precipitate hot flash episodes 1, 7

Secondary Medical Causes to Rule Out

Before attributing temperature dysregulation solely to menopause, thyroid disease and diabetes must be excluded, as these conditions can mimic or exacerbate vasomotor symptoms 1, 8

Important Clinical Considerations

Common Pitfalls

• Hot flashes should never be dismissed as "normal for age"—they significantly impact quality of life and warrant treatment 1

• Core body temperature fluctuations occur in both symptomatic and asymptomatic postmenopausal women, so the presence of temperature variation alone does not distinguish between groups 9

• In women with breast cancer history, cancer treatment-related causes should not be overlooked, as these patients may experience particularly severe and prolonged symptoms 1

Assessment Approach

• Evaluate frequency and severity of hot flashes and night sweats, and assess their impact on daily activities 8

• Consider using a hot flash diary to identify specific triggers for individual patients 1

• Laboratory evaluation may include estradiol, FSH, LH, and prolactin as clinically indicated, though FSH is unreliable in women with prior chemotherapy, pelvic radiation, or those on tamoxifen 8