Beginning a first job is a major life shift, and new research from the University of Cambridge shows how it shapes young adults’ health habits. The study found that when people start working, their physical activity increases sharply—but this boost fades over time. Meanwhile, sleep decreases slightly and stays low.

The research looked at data from over 3,000 people aged 16 to 30 who started work between 2015 and 2023. The biggest rise in physical activity came from those in semi-routine jobs like cleaning or hairdressing, routine jobs like waiting tables, or technical roles. On average, physical activity rose by the equivalent of 28 minutes of moderate exercise (like cycling) per day after starting work. However, this activity dropped by around seven minutes per day with each passing year.

Variable gains

Men saw the biggest gains in physical activity—about 45 minutes of moderate exercise per day, compared to just 16 minutes for women. Workers without university degrees also had larger increases in activity than graduates. By contrast, people in office jobs or working from home saw little improvement, with remote workers even experiencing an initial drop in activity equivalent to 32 minutes of moderate exercise per day.

Sleep was another casualty of starting work. Most young adults lost about 10 minutes of sleep per night after starting their jobs. Over time, those with university degrees regained their pre-work sleep patterns, but non-graduates kept losing sleep—around three minutes per night each year.

Diet remained unchanged, with no significant increase in fruit and vegetable consumption after starting work.

Why it matters

This matters because young adulthood, often seen as a time of peak health, is also when the seeds of long-term illnesses like heart disease and diabetes are often sown. Health guidelines suggest young adults should aim for 150 minutes of moderate physical activity per week, seven to nine hours of sleep per night, and at least five servings of fruit and vegetables daily. But the demands of work—long hours, tight schedules, and sedentary roles—can disrupt these goals.

“Starting work has a big impact on how we live,” the researchers explained. “Many people become more active at first, but this doesn’t last. Those working from home or in sedentary jobs are particularly at risk of losing out on exercise.”

Employers could make a difference by creating workplaces that encourage healthy habits, such as offering time for physical activity, promoting better sleep routines, and supporting healthier diets. This could mean healthier employees, fewer sick days, and lower healthcare costs.

For individuals, especially those working remotely, small steps can help offset the health risks of modern work. Taking a walk before or after work, or even during a lunch break, can go a long way toward maintaining physical activity. Building good habits early on may prevent bigger health problems down the road.