Most long-term illnesses do not appear suddenly. Conditions such as diabetes, heart disease, and dementia often develop slowly over many years, as small changes build up inside the body.
By the time symptoms appear, damage may already be well underway.
Researchers at the Buck Institute for Research on Aging believe medicine needs to shift its focus from treating disease after it starts to detecting risk much earlier—before people even feel unwell.
In a new perspective published in Cell Systems, the scientists describe how diseases often begin with subtle biological changes that go unnoticed.
They call this process the “long tail” of biology. Instead of being caused by one single factor, most chronic diseases result from the combined effects of genetics, lifestyle habits, environmental exposures, stress, sleep quality, and even changes in gut bacteria.
Over time, these influences can weaken the body’s resilience and increase the chance of illness.
Professor Nathan Price, a senior author of the paper, says that by the time many diseases are diagnosed, the body has already been drifting off course for years.
He believes new technologies could help detect those early shifts by tracking what is normal for each person and identifying when something begins to change.
Type 2 diabetes is a good example. Biological warning signs related to inflammation, metabolism, and insulin function can appear 10 to 15 years before blood sugar levels become high enough for a diagnosis. If doctors could identify these early signals, people might be able to take action to delay or even prevent the disease.
The researchers propose a new approach that treats each individual as their own baseline for health. Instead of comparing patients to population averages, doctors could monitor personal trends over time. Small changes that might look normal in a general population could be meaningful warning signs for a specific person.
Advances in technology are making this idea more realistic. Wearable devices such as smartwatches can continuously track heart rate, sleep patterns, and physical activity.
At the same time, modern laboratory tests can measure thousands of biological markers from simple samples like blood, saliva, or urine. Artificial intelligence can then analyze this huge amount of data to find patterns that humans might miss.
Lead author Noa Rappaport says the goal is to protect health rather than wait for illness to appear. However, the researchers acknowledge that challenges remain. Advanced testing can be expensive, and health systems are still mainly designed to treat disease rather than monitor long-term wellness. Ensuring that new preventive tools are accessible to everyone will be essential to avoid widening health inequalities.
Despite these obstacles, the team believes a major shift in medicine is coming. By combining wearable technology, advanced testing, and artificial intelligence, future health care may focus on keeping people healthy for as long as possible—not just treating them when they get sick.
