Introduction
A hot flash (HF) is a sudden increase in the body temperature, especially in the upper body. The body's warmth is accompanied by sweating, flushing, and chills. Sweating may be seen, especially on the face, neck, and chest. HF may appear with menopause, end in post-menopause, or remain for the rest of life.
What Is a Hot Flash?
A hot flash is a sudden feeling of heat, sweating, and discomfort. HF is considered to be a common and uncomfortable symptom of the menopause transition. Menopause is a period considered a natural time when the ovaries stop producing eggs and the period stops. Doctors usually mention HF as having vasomotor symptoms (VMS). It was estimated that more than two-thirds of individuals who are assigned female at birth (AFAB) in North America who are in menopause transition exhibit HF. Other females who do not secrete sufficient estrogen, either due to chemotherapy or if their ovaries are removed for some other reason, exhibit HF.
What Are the Causes of Hot Flashes?
HF is considered to be caused mainly by alterations in the levels of hormones. Variations in hormone levels occur during or after menopause. Researchers have thought that decreased estrogen levels may cause the body’s thermostat (hypothalamus) to become more sensitive to slight variations in body temperature. The hypothalamus (the body’s thermostat) regulates the body temperature. Hence, when it thinks the body is warm, it starts a chain of reactions to regulate the body temperature. In response, HF occurs to cool down the body. Other causes of HF, or night sweats, are infrequent, except menopause.
Other causes include,
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Medications.
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Cancer of certain types.
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Side effects of cancer treatment.
Though HF is related to menopause, not all women suffer from HF. Those who have HF are not clear about why it occurs. Risk factors involved in HF include,
- Smoking: Women with the habit of smoking are usually affected by HF.
- Obesity: Women with a high body mass index are linked to HF.
- Race: Black women are more susceptible to HF during menopause when compared to women of other races. Asian women are the least affected by HF.
What Are the Symptoms of Hot Flashes?
The symptoms of HF include,
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A sudden increase in warmth, especially in the upper body, including the chest, neck, and face.
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The appearance of flushing on the skin is red, blotchy skin.
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Appearance of rapid heartbeats.
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Sweating on the upper body.
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There is a feeling of chills as there is a rise in HF.
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Experience anxiety.
Symptoms of HF may vary among females. Some may experience HF for a minute or two, and some may feel it for five minutes or more. The symptoms may be mild, or they may disrupt daily activities. HF is experienced daily and may last for seven to ten years.
What Are the Complications of Hot Flashes?
HF can affect the quality of life, thereby affecting daily activities.
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Sleep disruption.
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Increased risk of heart disease.
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Bone loss.
What Are the Endocrine Causes of Hot Flashes?
HF was related to estrogens. This was confirmed when estrogen therapy eliminated HF. Researchers thought that estrogen reduction was not the only reason for HF. This was because the estrogen levels were unaffected in plasma, urinary, and vagina. They also observed that a medication called clonidine reduced HF, but it did not affect estrogen levels. One more reason is low levels of estrogen among prepubertal girls, but they do not exhibit HF.
Researchers observed a relationship between HF and luteinizing hormone (LH) pulses. As the work progressed, it was found that females with gonadotropin deficiency had HF but did not show LH pulses. Women with hypothalamic amenorrhea exhibited LH pulses but did not have HF. It was observed that women with LH suppression occurred due to GnRH (gonadotropin-releasing hormone) compounds, those with pituitary insufficiency and hypoestrogenism, and those women who have undergone hypophysectomy exhibited HF.
The research found that the opiate system was thought to be present as a cause of HF. Research by Lightman found that an opiate antagonist successfully reduced HF and LH pulse frequencies. Due to the failure of other research to reproduce the same results, the involvement of the opiate system as a cause of HF was considered inconsistent. Norepinephrine (NE) is found to play an important role in thermoregulation. These act through α2 adrenergic receptors. When NE is injected into the preoptic hypothalamus, it causes heat dissipation, followed by a decrease in core body temperature (Tc). Along with this, it was found that gonadal steroids can modulate central NE activity.
Researchers also found that estrogen modulates brain adrenergic receptors. Based on the theories, it was concluded that increased brain NE, along with estrogen withdrawal, are considered part of the etiology of HF. HF during menopause is mainly due to a decrease in estrogen levels. Estrogen hormone and testosterone regulate a part of the brain called the hypothalamus. The hypothalamus regulates the body temperature. Some of the medications may be responsible for causing HF. Medications directly affect the levels of estrogen in the body. Few other medications may affect the hypothalamus-pituitary-adrenal (HPA) axis.
The HPA axis coordinates the hypothalamus and hormone-producing glands called pituitary and adrenal glands. The HPA axis helps maintain equilibrium by constantly sending chemical messages to and from the hypothalamus. This includes body temperature. Whenever the hypothalamus does not respond, or chemical messages are disrupted, vasomotor symptoms may appear.
Medications that can cause HF include
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Chemotherapy.
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Opioids.
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Tricyclic antidepressants.
Hyperthyroidism can produce vasomotor symptoms. The thyroid gland interacts with the hypothalamus and pituitary glands to produce the proper amount of thyroid hormones. The thyroid gland is overactive in the case of hyperthyroidism. It may disrupt the loop and overstimulate the hypothalamus. This is responsible for the appearance of vasomotor symptoms.
Hypogonadism may cause HF. Low testosterone can be seen in hypogonadism among males. Small amounts of testosterone are converted into estrogen in the body. When there are low levels of testosterone present, then even estrogen levels decrease, leading to HF. In anxiety, the body secretes a hormone called cortisol. This hormone helps in the fight-or-flight response to the threat. This hormone causes an increased heart and respiratory rate. These responses make the body heat up, resulting in HF. In the condition known as Carcinoid syndrome, increased levels of the hormone serotonin occur. This response causes the widening of blood vessels; hence, there is an increased blood flow beneath the skin.
Conclusion
A hot flash is a sudden rise in body temperature, especially in the upper part of the body. HF may be caused mainly by the menopause transition. Various other causes of HF are present. Many hormones are involved in causing HF. A drop in estrogen levels may be related to HF. Hence, knowing about HF, its causes, symptoms, and endocrine causes becomes important. Knowing the condition may help in an early diagnosis. This further helps in achieving effective treatment.
