Longevity Estimator Tool

What affects life expectancy

How long you live depends on several factors – your genes, lifestyle choices, where you live, and your circumstances. Understanding what matters most can help you make decisions that could genuinely affect your health and longevity.

Your genes matter, but less than you think

Your genes play a part in how long you’ll live, but probably less than you’d expect. Research shows that genetics accounts for only about 25% of how long people live, and the specific genes involved aren’t yet fully understood.

Here’s the encouraging bit: for most of your life, roughly the first 70-80 years, your lifestyle choices have much more impact than your genes. It’s only when you reach your eighties and beyond that genetics begin to play a bigger role in maintaining your health.

If you come from a long-lived family, that’s good news. People whose parents or siblings live to very old ages tend to stay healthier longer and live longer themselves.

If you have a parent who reached 100, you’re less likely to develop age-related diseases by age 70 compared to most people.

Your lifestyle choices

Smoking

If you smoke, this is the single worst thing for your lifespan. Smoking cuts roughly 5 years off your life and is linked to 21 different diseases. The good news? Your body starts repairing itself as soon as you quit, regardless of your age.

Staying active

Regular exercise is one of the best things you can do for a long life. Being active protects against 17 different diseases and significantly affects how you age. You don’t need to run marathons – even regular walking makes a real difference.

What you eat

Your diet matters for longevity. A study at the University of Florida found that people who swapped sugary drinks and processed meat for whole grains and nuts lived longer. The research shows that it’s never too late to improve your diet and reap the benefits.

Drinking alcohol

Moderate drinking doesn’t seem to hurt longevity much – heavy drinking only reduces life expectancy by about 6 months. But “moderate” is key here.

Your weight

Being significantly overweight does affect lifespan, but perhaps less than you’d think. Obesity reduces life expectancy by about 8 months on average. It’s the second-biggest lifestyle risk factor after smoking, but the relationship is complex and varies between individuals.

Your circumstances

Education

Your educational level has a significant impact on how long you live. Men with higher education live about 7 years longer than those with the lowest education levels. For women, the difference is about 5 years.

Education affects longevity because it typically leads to better jobs, higher income, and the knowledge and skills to make healthier choices throughout life.

Income and job

Your income and the type of work you do have a significant impact on your health. Research from Imperial College London found that having a low socioeconomic status reduces life expectancy by about 2 years, almost as much as smoking or being inactive.

Men in higher-paying jobs live about 7 years longer than those in the lowest-paid work. This isn’t just about money – it’s also about job security, working conditions, and the stress that comes with financial uncertainty.

Where you live

Your postcode affects your lifespan more than you might expect. People in the most deprived areas live about 9 years less (for men) or 7 years less (for women) compared to those in the wealthiest areas.

This represents one of the biggest health inequalities in the UK today.

Health conditions you might develop

Chronic diseases

If you develop long-term health conditions, especially multiple ones, this significantly affects both the length of your life and the quality of those years.

Cancer and heart disease have the biggest impact on life expectancy.

The good news is that many chronic diseases can be prevented, or their onset delayed, through the lifestyle choices mentioned above.

Blood pressure and cholesterol

High blood pressure and cholesterol are risk factors for a shorter life, but they’re manageable.

High blood pressure typically reduces life expectancy by about 1.6 years, but this can often be controlled with medication and lifestyle changes.

Your environment and support

Healthcare access

Having access to good healthcare when you need it obviously affects how long you live.

The dramatic increase in life expectancy over the past century was mainly due to better medical care, cleaner water, safer food, and improved living conditions.

Your living conditions

The environment you grew up in and live in now affects your health.

Poor conditions early in life can speed up ageing, but there’s always opportunity to make changes that improve your health, even later in life.

Your relationships

Maintaining good relationships and social connections is associated with increased longevity.

This might be partly why more educated people tend to live longer – they’re more likely to form and maintain supportive relationships, including marriage.

It’s not all doom and gloom though

A major study from Oxford Population Health found that your environment and lifestyle choices account for 17% of the differences in lifespan, while genetics account for less than 2%. Your choices matter far more than your genes.

Even better, research shows that adopting a healthy lifestyle later in life still makes a real difference to how long you live, especially if you have genetic risk factors for a shorter life.

It genuinely is never too late to make positive changes.

The research consistently shows that while your genes set the baseline, the choices you make and the life you build have far more influence on how long you live.

The most important factors, such as quitting smoking, staying active, eating well, and maintaining healthy relationships, are within your control throughout your life.

Small, consistent changes can make a real difference, no matter when you start.