Many researchers believe the effects of aging are a result of numerous genetic and environmental factors, and these effects vary from person to person.

The genetic aging theory suggests that, just like hair color and height, our lifespan is influenced by the genes we inherit from our parents.

Such a theory may ring true; studies have shown that children of parents who have a long lifespan are more likely to live a longer life themselves.

And research from Sweden’s Karolinska Institutet (resource no longer available at www.nature.com) – published in 2013 – suggested that the aging process is influenced by mitochondrial DNA that we inherit from our mothers.

The team found that female mouse models passed mutations in mitochondrial DNA – which they accumulated through environmental exposures during their lifetime – to offspring, which reduced their lifespan.

But while evidence for the genetic aging theory is strong, the fact remains that healthy aging and longevity is largely influenced by our environment – that is, what we eat, how much we exercise, where we live and the compounds and toxins we are exposed to throughout our lifetime.

Our DNA accumulates damage from environmental exposures as we age. While cells are capable of repairing most of this damage, sometimes it is beyond repair.

This most often occurs as a result of oxidative stress, where the body does not possess enough antioxidants to fix the damage caused by free radicals – uncharged molecules that cause DNA damage. Oxidative stress has been identified as a key player in the aging process.

Another major cause of DNA damage is the shortening of telomeres. These are the caps at the end of each DNA strand that protect our chromosomes – the thread-like structures that contain all our genetic data.

Telomeres are the caps at the end of each DNA strand that protect our chromosomes; their shortening speeds up the aging process.

Telomeres naturally shorten as we age, reducing in length each time a cell divides. But when telomeres become too short, they are no longer able to protect the chromosomes, leaving them susceptible to damage that can lead to premature aging and disease development.

A recent study from the UK’s University of Cambridge suggests that telomere shortening as a result of environmental exposures may even be passed to offspring.

The team found that rats that had lower oxygen in the womb during pregnancy – often caused by smoking during pregnancy in humans – gave birth to offspring with shorter telomeres than rats that had higher oxygen exposure.

What is more, the oxygen-deprived offspring were found to have abnormalities in their blood vessels – a sign of faster aging and a predisposition to heart disease.

“We already know that our genes interact with environmental risk factors, such as smoking, obesity and lack of exercise to increase our risk of heart disease,” notes senior author Prof. Dino Giussani, from the Department of Physiology Development & Neuroscience at Cambridge, “but here we’ve shown that the environment we’re exposed to in the womb may be just as, if not more, important in programming a risk of adult-onset cardiovascular disease.”

The evidence for telomere length as a major player in the aging process has become so strong that researchers are looking to use telomeres as a biomarker for age-related diseases.

Last year, for example, Medical News Today reported on a study in which researchers revealed how a distinct telomere pattern in the blood could be used to predict cancer development.

But what if researchers found a way to extend telomere length to protect against age-related diseases and the other effects of aging? Or what if they identified a strategy that could protect against oxidative stress?

Such approaches may not be too far from reality.

1. Low sex drive

Testosterone plays a key role in libido (sex drive) in men. Some men may experience a decline in sex drive as they age. However, someone with low T will likely experience a more drastic drop in their desire to have sex.

2. Difficulty with erection

While testosterone stimulates a man’s sex drive, it also aids in achieving and maintaining an erection. Testosterone alone doesn’t cause an erection, but it stimulates receptors in the brain to produce nitric oxide.

Nitric oxide is a molecule that helps trigger a series of chemical reactions necessary for an erection to occur. When testosterone levels are too low, a man may have difficulty achieving an erection prior to sex or having spontaneous erections (for example, during sleep).

However, testosterone is only one of many factors that aid in adequate erections. Research is inconclusive regarding the role of testosterone replacement in the treatment of erectile dysfunction.

In a review of studies that looked at the benefit of testosterone in men with erection difficulties, nearly halfTrusted Source showed no improvement with testosterone treatment. Many times, other health problems play a role in erectile difficulties. These can include:

• diabetes
• thyroid problems
• high blood pressure
• high cholesterol
• smoking
• alcohol use
• depression
• stress
• anxiety

3. Low semen volume

Testosterone plays a role in the production of semen, which is the milky fluid that aids in the motility of sperm. Men with low T will often notice a decrease in the volume of their semen during ejaculation.