Cortisol, sometimes referred to as the stress hormone, is released in order to cope with increased physical or mental demand on the body. A relationship between being under prolonged periods of stress and premature ageing has been suggested. In the future we could see drugs that influence the hormones, involved in the ageing process, become available on the market as anti-ageing remedies.
Cortisol is secreted by the adrenal glands, located in the adrenal cortex above the kidneys and is controlled by the hypothalamus in the brain. The hormone triggers responses that enable the body to react effectively in a “fight or flight” situation.
One of the main responses is an increase in metabolism. Cortisol is involved in glucogenesis, the production of glucose from non-carbohydrate substrates, such as pyruvate and lactate. It is also a facilitator of glycogenolysis, in which glycogen in the liver is converted into glucose. The result is a rise in blood glucose levels and a plentiful supply of glucose for respiration to generate energy to “fight” or “fly” away from danger.
Increased levels of cortisol stimulate vasoconstriction (narrowing of blood vessels), increasing blood pressure to enable fast transport of necessary substances to tissues.
Another effect is the suppression of the immune system and the inflammatory response by inhibiting the release of histamines (the chemical released when cells are damaged). Energy is diverted from this short term low priority activity to where it is needed most. Cortisol, and its synthetic equivalents, is often used to treat inflammatory and rheumatoid diseases and allergies due to its dampening effect on the immune system.
However, serious problems can arise if cortisol secretion is not controlled. People with Cushing’s syndrome produce too much cortisol. The syndrome affects 10-15 people per million of the population every year, most of whom are aged 20-50. Too much cortisol disrupts the body’s natural metabolism, leading to upper body obesity with fat around the face and neck. Cortisol increases blood glucose and counteracts insulin so Cushing’s syndrome patients often develop diabetes.
Prolonged cortisol exposure leads to the break down of proteins, causing the skin to become thin and easily bruised and the appearance of purple stretch marks. Due to a suppressed inflammatory response the skin also heals poorly. Blood vessels become prominent and bulge through the skin as a result of high blood pressure.
Cushing’s sufferers may have difficulty bending and lifting due to weak bones. Over time, cortisol decreases bone formation due to inhibition of calcium absorption and can lead to osteoporosis. The syndrome is sometimes characterised by hunched shoulders and curvature of the spine.
Cortisol and another chemical, epinephrine, are involved in creating short term emotional memories. However, prolonged cortisol exposure inhibits memory retrieval, drawing parallels with the symptoms of Alzheimer’s and Dementia.
Further investigations with cortisol have shown that rats, administered with high levels of cortisol, experienced cortisol induced collagen loss in the skin 10 times greater than in other tissues.
Producing too little cortisol is also extremely dangerous. The body’s metabolism is greatly reduced, resulting in muscle weakness, weight loss and hypoglycaemia (low blood sugar). Deficient patients are often diagnosed after a series of collapses.
The main role of cortisol is to provide resistance to stress. High levels of stress and anxiety are already known to accelerate ageing. Stress is an established risk factor for many conditions, including heart disease, cancer, diabetes, obesity and Alzheimer’s, all of which increase in prevalence in older age groups.
Research has shown that cortisol levels increase with age. In young people, in a situation of stress, cortisol levels rise, but fall again in a matter of hours. However, in older people cortisol levels remain elevated for a few days.
Symptoms of Cushing’s syndrome are comparable to the signs of ageing, such as weak bones, hypertension and collagen loss in the skin. This suggests that by limiting cortisol levels, we can reduce the effects of ageing.
The hormone dehydroepiandrosterone (DHEA) is produced in the adrenal cortex and is a counter-regulator of cortisol. As age increases, cortisol levels increase and studies have shown that DHEA decreases.
DHEA has an antagonistic response to the effects of cortisol. Future anti-ageing drugs may act to increase levels of DHEA in the body to reduce the amount of cortisol. This would slow down processes like wrinkling of the skin, deterioration of the memory and weakening of bones. People could begin taking medication in their 20s and remain youthful beyond middle age. As well as a having an aesthetic benefit, a cortisol limiting drug could help prevent conditions, such as heart disease, diabetes and cancer, associated with ageing.
The prospect of a drug that keeps you youthful and healthy is tantalising for many, but eternal youth comes at a price. When interfering with hormones we are meddling with our bodies’ fine tuned equilibria. The balance is vital in the functioning of the body and survival, but we are yet to fully understand the effects of the chemicals involved and the relationships between them. There are already patients who develop Cushing’s syndrome after taking cortisol medications prescribed for inflammatory and rheumatoid diseases or illegal recreational steroids. Cortisol is an essential hormone in the body and is required in specific quantities. Both too much and too little can prove fatal. “Lifelong” youth is not worth the consequences to health.