More than 80% of women experience hot flashes (HFs) during menopause. While there are other causes of hot flashes, they are most common when women undergo peri-menopause or menopause. Hot flashes are described as transient sensations of heat, sweating, flushing, anxiety, and chills lasting for 1-5 minutes (2). Hot flashes account for a significant proportion of sleepless nights for women in the peri-menopausal stage (3). Most peri-menopausal women have hot flashes for 1-2 years, but up to 15% may have persistent hot flashes for up to 30 years (4). This article will discuss the cause, symptoms, lab tests, and root cause treatment of hot flashes.
What Causes Hot Flashes
A hot flash is a sudden feeling of heat, sweating, flushing, and even anxiety. Hot flashes most commonly happen around menopause due to changing hormone levels. It's not clear exactly how hormonal changes cause hot flashes. But most research suggests that hot flashes occur when decreased estrogen levels cause your body's internal thermostat to become more sensitive to slight changes in body temperature. When your body gets too warm, it starts a chain of events, including the hot flash, to cool you down (6,7).
One study with over 3,000 participants showed that hot flash prevalence increased with higher FSH concentrations. The conclusion was that annual FSH concentrations (but not other hormones tested) are associated with the prevalence and frequency of hot flashes symptoms in women in midlife (8).
This drop in estrogen, as mentioned above, and an increase in FSH are typical in menopausal women.
Other Conditions That Can Cause Hot Flashes
Researchers from The Department of Psychiatry and Behavioral Neuroscience and Obstetrics and Gynecology, Wayne State University School of Medicine, suggested that norepinephrine may also play an important role in thermoregulation (how your body regulates its temperature).
They believe that hot flashes in menopausal women are caused by a narrow window allowed for thermoregulation, and when the body hits its threshold, the hot flashes are provoked.
Hot flashes can also be caused by reasons other than menopause, including medication side effects, thyroid problems, changes in cortisol levels, anxiety, food sensitivities, and side effects of cancer treatment.
Hot Flashes Signs and Symptoms
Hot flashes can show up differently for everyone. During a hot flash, you might have:
- A sudden feeling of warmth spreading through your chest, neck, and face
- A flushed appearance with red, blotchy skin
- A rapid heartbeat
- Perspiration, mostly on your upper body
- A chilled feeling as the hot flash lets up
- Feelings of anxiety
The frequency and intensity of hot flashes can vary. A single episode might last one or two minutes or up to 5 minutes. Hot flashes can be so intense that they disrupt activities of daily living, including sleep. How often hot flashes occur varies among women, but most who experience them report hot flashes daily (5).
Functional Medicine Labs to Test for Root Cause of Hot Flashes
We can test hormones by checking serum (blood), urine, or saliva. Most providers have access to testing serum through your standard lab. The issue with serum blood testing is that you can check the levels of hormones circulating at that time, but you can't check how the metabolites (byproducts) are working with your body. In functional medicine, if possible, we recommend urine or saliva panel testing because it is more accurate, looking for metabolites to aid in the understanding of how those levels are impacting an individual's body.
This test is an extensive sex and adrenal hormone profile. It measures sex hormones, cortisol, organic acids, and oxidative stress metabolites. This is important to understand the effects those levels have on that individual's body.
*Metabolites are byproducts of the hormone chemical pathways.
These tests measure all major female hormones in serum, such as estradiol, testosterone, progesterone, follicle-stimulating hormone (FSH), luteinizing hormone (LH), estriol (E3), and sex hormone binding globulin.
When the thyroid is unbalanced, it can cause temperature regulation issues, mimicking hot flashes.
Having a full thyroid panel performed gives a comprehensive picture of the downstream thyroid hormones providing valuable insight into the health and well-being of an individual.
Conventional Medicine Treatment for Hot Flashes
The most common conventional treatment for hot flashes concerns addressing menopausal symptoms since this is the most common reason for hot flashes to occur.
Hormone Replacement Therapy
For others, if the hot flashes are caused by peri-menopause or menopause, hormone replacement therapy (HRT) is a standard treatment option. (5)
Hormone replacement therapy is when hormones are used to supplement the body's lack of production of certain hormones, especially sex hormones like estrogen.
There are two main types of estrogen therapy:
- Systemic hormone therapy. These come in pill, skin patch, ring, gel, cream, or spray form. They typically contain a higher dose of estrogen.
- Low-dose vaginal products. Low-dose vaginal preparations of estrogen come in cream, tablet, or ring form. These minimize the amount of estrogen absorbed by the body. Because of this, low-dose vaginal preparations are usually only used to treat the vaginal and urinary symptoms of menopause.
Bioidentical Hormone Replacement Therapy
One type of hormone replacement therapy is bioidentical hormone therapy. These hormones are plant-derived, chemically similar, or structurally identical to our body's naturally made hormone compounds. The thought is that if the hormones are similar to those in our body, we can absorb and use them better.
*There are risks associated with hormone replacement therapy. Make sure to discuss the risk and benefits of each type with your provider before starting any new kind of treatment.
Functional Medicine Treatment of Hot Flashes
Fruits and vegetables: Fruits and vegetables are packed with vitamins, minerals, fiber, and antioxidants. In a one-year intervention study in over 17,000 menopausal women, those eating vegetables, fruit, fiber, and soy experienced a 19% reduction in hot flashes compared to the control group. These women also lost, on average, ~2 kg between baseline and Year 1 compared to the control group, providing the opportunity to examine whether this dietary intervention and weight change were associated with reducing or eliminating hot flashes.
Phyto-estrogen-containing compounds: There has been controversy surrounding phytoestrogens in the diet, but the most recent research suggests they may benefit health- especially for women going through menopause. In a review of 15 studies ranging from 3 to 12 months, phytoestrogens, including soy, isoflavone supplements, and red clover, were found to lower incidences of hot flashes compared to control groups, with no serious side effects (15).
Healthy fats: Three randomized controlled trials involving 483 women suggested that omega-3 supplements are of benefit in alleviating hot flashes in menopausal women (12). There are not many studies on this subject, and more research needs to be done. Yet adding healthy omega-3 foods show many other health benefits and may be worth adding to the diet. Foods highest in omega-3 fatty acids include fatty fish, such as mackerel, salmon, and anchovies, and seeds like flax seeds, chia seeds, and hemp seeds (13).
Foods to Avoid
Added sugars and processed foods: High blood sugar, insulin resistance, and metabolic syndrome have been linked to a higher incidence of hot flashes in menopausal women (16,17,18).
Caffeine and Alcohol: Caffeine and alcohol have been associated with more significant hot flash responses in post-menopausal women (19). In a study of 196 menopausal women, caffeine and alcohol intake increased the severity of hot flashes but not their frequency.
Herbs and Supplements
Some herbs and supplements have been used for centuries to treat the side effects of hot flashes. Many are currently being researched and used clinically.
Black Cohosh: This herb shows excellent promise for relief of hot flash symptom relief and helps with mood disorders with an overall positive safety profile of up to 6 months (22).
Phytoestrogen Herbal Tea Capsule: A study was conducted on 82 women who complained of hot flashes during their menopause period. Half of the women received a capsule with 450 mg phytoestrogen herbal extracts, and the other half received a placebo for eight weeks. There was a significant difference in the severity and duration of hot flashes in the group who were given herbal tea capsules (25).
Licorice Root: Another study showed that licorice root effectively reduces the frequency and severity of hot flashes. Licorice significantly decreased daily hot flash frequencies during the eight weeks of the study compared to no decrease found in the placebo group.
Cognitive behavioral therapy (CBT): CBT has been recommended by the North American Menopausal Society for reducing bothersome hot flashes symptoms. This is done by changing behavioral choices and reducing norepinephrine to alter symptoms. CBT may include education, motivational interviewing, paced breathing, or relaxation (23).
Hypnosis: Hypnosis has been recommended by the North American Menopause Society for treating menopausal symptoms and poses little risk. A randomized clinical trial involving 187 post-menopausal women reporting a minimum of 7 hot flashes per day showed a reduction of 74% with hypnosis compared to 17% for the control group. The mean decrease in hot flash score was 80% for the clinical hypnosis intervention compared to 15% for the control.
Aromatherapy: In a double-blinded 12-week clinical crossover trial of 100 women, lavender essential oil reduced hot flash frequency by 50% compared to a <1% reduction in the placebo. Three other RCTs of aromatherapy combined with massage found aromatherapy massage to be more beneficial than massage alone in reducing hot flashes and psychological symptoms.
*Some women don't need any treatment for hot flashes and choose to deal with them naturally.
Hot flashes affect 80% of women during menopause. They account for sleepless nights and uncomfortable temperature changes daily for some individuals. There can also be other causes for hot flashes, such as thyroid hormone changes, anxiety, or side effects of medications. It is important to rule out other causes of hot flashes to address the root cause if needed.
Research has suggested that when estrogen levels decrease, the hypothalamus (temperature regulator) has a hard time adjusting and causes rapid temperature changes to compensate. Other studies have suggested changes in cortisol levels, or norepinephrine can contribute to hot flashes.
Nutrition, herbs and supplements, and lifestyle factors can help decrease the intensity and frequency of hot flashes. It is important to learn what your body responds to when experiencing hot flashes, as this will affect your daily life.
Lab Tests in This Article
- The Midlife Women’s Health Study – a study protocol of a longitudinal prospective study on predictors of menopausal hot flashes | Women's Midlife Health | Full Text (biomedcentral.com) (1)
- What causes hot flushes? The neuroendocrine origin of vasomotor symptoms in the menopause - PubMed (nih.gov)
- The relationship of longitudinal change in reproductive hormones and vasomotor symptoms during the menopausal transition - PubMed (nih.gov)
- Evaluating urinary estrogen and progesterone metabolites using dried filter paper samples and gas chromatography with tandem mass spectometry
- The Free Hormone Hypothesis: When, Why, and How to Measure the Free Hormone Levels to Assess Vitamin D, Thyroid, Sex Hormone, and Cortisol Status - PMC (nih.gov)
- Effect of omega-3 supplements on vasomotor symptoms in menopausal women: A systematic review and meta-analysis - PubMed (nih.gov)
- Effects of a dietary intervention and weight change on vasomotor symptoms in the Women’s Health Initiative - PMC (nih.gov)
- Efficacy of phytoestrogens for menopausal symptoms: a meta-analysis and systematic review - PubMed (nih.gov)
- Vasomotor symptoms and insulin resistance in the study of women's health across the nation - PubMed (nih.gov)
- Association between menopausal symptoms and metabolic syndrome in postmenopausal women - PubMed (nih.gov)
- An exploratory study on perceived relationship of alcohol, caffeine, and physical activity on hot flashes in menopausal women (scirp.org)
- The International Menopause Study of Climate, Altitude, Temperature (IMS-CAT) and vasomotor symptoms - PubMed (nih.gov)