Introduction

With ageing, our body undergoes several changes, and hormones have a big role in it. Hormones are chemical messengers that affect everything from energy levels and metabolism to mood, fertility, bone strength, and many other aspects.

Ageing affects people differently, yet most hormonal changes occur in a particular pattern in men and women. This article delves into the ways in which our hormone levels change with age, what this means for our health, and how these changes influence our mood and abilities as we grow older.

Hormonal changes in women

To understand the effects of ageing, it is first important to understand the main female hormones:

• Oestrogen: aids in the formation of the eggs and the growth of the uterine lining
• Progesterone: maintains the lining of the uterus and prepares it for pregnancy
• FSH (follicle-stimulating hormone): stimulates the formation and development of ovarian follicles
• Inhibin: signals to decrease FSH to control how many eggs grow.
• LH (luteinising hormone): causes ovulation

As a woman ages, the number of eggs remaining in the ovaries decreases, but the cycles continue to be regular, and ovulation occurs as usual. As women get older, the number of eggs in her ovaries decreases further. The eggs are stored in structures called follicles that also produce oestrogen, progesterone, and inhibins. These hormones are mostly produced by the growing follicles, and therefore, when the follicles are few, the hormone levels drop. In order to stimulate the ovaries, the brain enhances FSH and LH. Under normal circumstances, the brain is told by oestrogen and inhibin to decrease hormone production, but when these hormones drop, the brain increases FSH and LH production.¹

Menopausal transition

Hormones such as AMH (Anti-Mullerian hormone) and Inhibin B, which are markers of ovarian reserve, also decrease. This process is called the menopausal transition, and it starts off slowly.

It happens at an average age of 46 years but can start anytime between 34 and 54 years. During this stage the cycles become progressively anovulatory; that is, ovulation does not take place and the egg is not released; only the uterine lining is shed.

At this stage, FSH levels keep on rising. These changes show that the body is trying to keep the reproductive system working, even though the ovaries are slowly shutting down.^1,2

Early menopausal transition

Due to the low egg supply, the changes become apparent and the cycles become irregular. This phase is called early menopausal transition—this is the first stage of menopause. The cycle changes are not apparent in this phase.²

Late menopausal transition

Late menopausal transition is characterised by the delay in periods, missed periods, or increased length of the cycle. This phase ends with the final menstrual period, resulting in menopause.²

Menopause

Menopause occurs when all the eggs have been exhausted and the woman has not had her period for twelve months.

The average age is 51 years. The range could be anywhere from 40 to 60 years.¹

Symptoms of menopause:

• Hot flashes
• Mood swings
• Sleep issues
• Vaginal dryness

The symptoms of menopause are mainly due to the decrease in oestrogen levels.² Since the ovary is no longer functioning, the two important female hormones, namely oestrogen and progesterone, also stop being produced.³

Post menopause

After menopause, FSH and LH levels remain higher than before menopause, though not as high as during the transition. DHEA and testosterone also decrease. For up to 10 years after menopause, the ovaries still produce a little testosterone. The body makes small amounts of oestrogen by converting testosterone into oestrogen.²

Hormonal changes in men

The changes in male reproduction are not as pronounced as in females. The testes function declines, and testosterone levels fall; this is called andropause. Men produce sperm throughout their lives, but their sperm quality decreases with age. The quantity of semen decreases as sperm motility slows down and their morphology becomes abnormal, which creates barriers for successful egg fertilisation.

• The DNA of sperm cells shows increasing damage, which reduces the chances of successful fertilisation
• A natural reduction in testosterone levels starts when men reach between 20 to 30 years old and continues throughout their lives
• The annual decrease in testosterone occurs at 1% to 2% per year
• Testes volume decreases by 30 percent in males who have reached age 75 and above
• Sertoli cells (which help support sperm production) also reduce in number
• FSH and LH are somewhat elevated, whereas Inhibin B levels fall
• The symptoms of this condition include diminished libido and sexual dysfunction as well as muscle weakness, weakened bones, and depression
• The ageing process causes a decline in fertility^1–3

Hormonal Shifts Common to Both Sexes

Growth hormone

Growth hormone (GH) has multiple functions, but only bone growth is talked about commonly.

The hormone regulates both fat and sugar metabolism, as well as supports muscle protein synthesis and helps in calcium absorption.

The ageing process leads to a condition known as Somatopause which represents decreased growth hormone production.

The liver releases insulin-like growth factor 1 (IGF-1), a special protein, after receiving a signal from growth hormone. IGF-1 functions as the primary messenger to execute GH-related effects in the human body.

GH and IGF-1 levels grow until adolescence and then decrease as a person ages.

Growth hormone levels decrease by about 15% with each decade beginning at the age of thirty. This ultimately lead to reduced IGF-1 levels.

Ageing results in muscle and bone loss alongside increased belly fat and reduced heart function (cardiac output).

The loss of muscle strength and muscle mass together results in slower movement, which increases the likelihood of falling and impacts overall physical strength.

Lower GH levels in the body may cause additional symptoms, including skin thinning, poor sleep quality, and altered blood clotting patterns.^1,4

Thyroid

The thyroid gland undergoes age-related transformations, which leads to increased thyroid problems as people get older, with hypothyroidism (low thyroid levels) as the most common condition.

Older adults have higher chances of developing autoimmune thyroid diseases and thyroid nodules (small swellings), which result in either underactive or overactive thyroid function.

Subclinical hyperthyroidism is a condition in which thyroid hormone levels are slightly high but without clear symptoms. It can lead to heart problems as well as bone fragility and memory loss.

Older adults experience thyroid hormone variations that differ between individuals; the most common presentation usually is the thyroid gland becoming less active during this period.

Also, during ageing, thyroid hormone T3 (main thyroid hormone) decreases and TSH (thyroid-stimulating hormone) increases, which signals for hormone production.^1,2

DHEA

The adrenal glands (small glands atop kidneys) produce a hormone known as DHEA and its sulfated form, DHEAS.

The body uses this hormone to synthesise both androgens (male hormones) and oestrogens.

Levels of DHEA fluctuate throughout life; it decreases significantly after birth before remaining low until the child reaches 7 to 9 years old. DHEA hormone levels increase gradually after puberty to achieve their maximum between 20 to 30 years old. DHEA levels begin their decline following the age of 30 while reducing at a rate of 2–3% each year for both men and women.

Older adults experience a reduction in these hormone levels, which drop between 20–30% of what they had when they were young.

These hormones protect the heart, boost immunity and also help with weight control.^1,3

Cortisol

Cortisol functions as a hormone that helps with stress response.

The natural daily pattern of cortisol is high during the morning and low during the night.

This pattern is deranged in older adults.

This affects the brain, metabolism and muscles.

People who develop higher cortisol levels are at increased risk of getting Alzheimer’s disease.⁴

Insulin

With ageing, the body becomes less sensitive to insulin, and this is known as insulin resistance.

This is the first step in the development of diabetes mellitus.

Older adults have higher chances of developing insulin resistance and type 2 diabetes, which makes them more vulnerable to developing other disorders and can result in early death.

Other hormones, including testosterone and GH, can also decrease during ageing and can cause insulin insensitivity.³

Others

The hormones that regulate hunger, such as ghrelin, cholecystokinin, and leptin, experience changes during ageing, which results in decreased appetite among older adults.²

Oxytocin decreases with ageing and affects social behaviour and also your muscles.⁵

Prolactin also increases in old age and is thought to be part of the body’s natural adjustments and not a sign of disease. That's why mildly elevated prolactin levels in healthy older adults with no symptoms aren't treated.⁴

The ageing process results in changes in the hypothalamus and pituitary gland, which affect metabolism, appetite, thirst, and overall hormones.⁴

Summary

Our bodies experience natural hormonal changes when we age. During menopause, women experience decreased levels of oestrogen and progesterone, and in men, testosterone decreases, which manifests as decreased fertility and causes other symptoms. Growth hormone, thyroid hormones, insulin, cortisol, and DHEA also decrease with changes in other hormones as well. Knowing about these hormonal transformations will help you to better understand your body while helping you understand ageing processes and its effects on your body.