Even if you work out, spending most of your day sitting may still adversely affect your health in ways that don’t become apparent until later in life. A recent study found that 35-year-olds who engaged in 30 minutes of vigorous exercise each day had cholesterol levels comparable to those of sedentary 30-year-olds, suggesting that vigorous exercise can offset up to five years of age-related decline in heart health.

Researchers analyzed data from adults aged 28 to 49 who participated in the Colorado Adoption/Twin Study of Lifespan Behavioral Development and Cognitive Aging. They tracked the time participants spent sitting each day and how often they engaged in moderate or vigorous physical activity. To isolate the effects of behavior from shared genetics and environment, the researchers also compared identical twins with differing activity and sitting patterns. They examined two key health markers: body mass index and the ratio of total to high-density lipoprotein cholesterol—a strong predictor of heart disease risk.

They found that people who spent more time sitting tended to have higher body mass index and worse cholesterol ratios as they aged. However, among those who sat for the same amount of time—about four hours daily—participants who exercised vigorously for at least 30 minutes daily had cholesterol profiles that resembled those of people five years younger. In some cases, vigorous activity was associated with health markers typical of people up to 10 years younger, but the protective effect weakened with longer sitting durations. In other words, exercise helped—but only to a point.

These findings suggest that while vigorous exercise offers clear benefits, reducing sitting time is just as important for maintaining good health. “Exercise snacks” can offset the harmful effects of prolonged sitting. Learn more in this clip featuring Dr. Rhonda Patrick and Brady Holmer.