A new study has found that unhealthy habits like smoking, drinking too much alcohol, and not getting enough exercise can already start harming mental and physical health by a person’s mid-30s.
These habits, if continued over time, are linked to worse health in later life.
The research, published in Annals of Medicine, highlights the need to take action early to improve the chances of staying healthy and happy in old age.
The study was carried out by a team of scientists in Finland, who followed a group of people for more than 30 years.
Most earlier studies have focused on people starting in their 40s or 50s, and usually followed them for about 20 years.
This new study stands out because it began when participants were much younger. The aim was to understand how bad habits affect not just the body, but also the mind.
The research followed hundreds of people who were born in the Finnish city of Jyväskylä in 1959. These participants were tracked through the years, starting with checkups and surveys at age 27, then again at 36, 42, 50, and 61. In total, 326 people took part in the early stages, and 206 continued into their 60s.
Researchers looked at both mental and physical health. Mental health was measured by asking questions about feelings of depression and overall emotional well-being. Physical health was measured using things like blood pressure, waist size, blood sugar, cholesterol, and other fat levels in the blood.
This information was combined into a “metabolic risk score” to show how at-risk someone might be for conditions like heart disease or diabetes. Participants also gave their own rating of their health each year.
The study tracked three major unhealthy habits: smoking, heavy drinking, and lack of exercise. Heavy drinking was defined as drinking more than 875 units of alcohol per year for women and 1,250 units for men. That’s roughly equivalent to 14–20 standard drinks per week. Physical inactivity meant exercising less than once a week.
The researchers found that people who had all three bad habits—smoking, drinking heavily, and not exercising—had worse health in their 30s than people who avoided these habits. Specifically, they had more symptoms of depression, worse results on physical health tests, and rated their own health lower.
The long-term impact was even greater. If people kept these habits over many years, their mental and physical health scores dropped even more. Each habit affected health in a slightly different way. Not exercising was especially bad for physical health. Smoking mainly affected mental health. Drinking heavily was linked to declines in both mental and physical health.
Dr. Tiia Kekäläinen, who led the study, said that unhealthy behaviors are known to raise the risk of diseases like cancer and heart disease, which cause most deaths worldwide. But what this study adds is that these risks start showing up in the mid-30s—not just in older age.
She emphasized that it’s best to address these habits early, before their effects build up over time. However, she also said that it’s never too late to make changes. Even switching to a healthier lifestyle in midlife can bring benefits later on.
One important point the study makes is that the connection between bad habits and poor health may go both ways. For instance, a person who is feeling stressed or unhappy might start drinking more as a way to cope.
This could then lead to problems in their personal life, which could make their mental health even worse. So it’s possible that poor health can lead to bad habits, not just the other way around.
The researchers also pointed out some limits in their study. For example, they treated smoking, drinking, and lack of exercise as equally harmful, even though some might be worse than others.
They also focused only on these three habits and didn’t include other important factors like diet or sleep, which could also affect health. Lastly, since the study focused on people born in the late 1950s in Finland, the results might not fully apply to younger generations or people in other parts of the world.
Still, the study sends a clear message: making healthier choices early in life can lead to better mental and physical health for decades to come.
If you care about alcoholism, please read studies that your age may decide whether alcohol is good or bad for you, and people over 40 need to prevent dangerous alcohol/drug interactions.
For more information about alcohol, please see recent studies about moderate alcohol drinking linked to high blood pressure, and results showing this drug combo shows promise for treating alcoholism.
The research findings can be found in Annals of Medicine.
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