Smartphones and Health: How Excessive Screen Time Puts Children at Risk

The authors of a study published in the Journal of the American Heart Association emphasized that the main causes of heart disease — such as obesity, high blood pressure, insulin resistance, and low levels of “good” cholesterol — often develop during childhood. These issues are worsened by a lack of physical activity, poor sleep, and unhealthy diets — all of which tend to accompany excessive time spent in front of screens.

Study Structure

The study analyzed data from two groups:

• 700 mothers and their children under the age of 10
• 411 adolescents under the age of 18

Screen time was recorded for:

• 94.1% of 6-year-old children
• 90.3% of 10-year-olds

On average:

• 6-year-olds spent about 2 hours per day on screens
• 10-year-olds spent 3.2 hours,
• Adolescents spent over 6 hours daily

Other Considered Factors

The researchers also accounted for various social and biological factors:

family income, mother’s education and age, gestational age at birth, number of siblings, and whether the mother smoked during pregnancy. Children's health was assessed regularly, including waist circumference, blood pressure, and cholesterol levels, adjusted for age, sex, and height.

Key Findings

Increased screen time was associated with:

• a sedentary lifestyle
• late bedtimes
• symptoms of ADHD
• a “Western diet” high in sugars and fats, and low in fruits and vegetables

Interestingly, among 10-year-olds, boys spent more time on screens than girls. However, among 6-year-olds, there were no gender differences.

Main Conclusions

The more time a child spent on screens, the worse their cardiovascular and metabolic health indicators were. This connection became stronger with age. For instance, a child who spends three additional hours per day on screens may face a 25–50% higher risk of developing cardiovascular problems compared to their peers. Sufficient and timely sleep could somewhat reduce these risks, but not eliminate them entirely.

The study highlights the importance of limiting screen time for children — even if that’s difficult in today’s world. Interestingly, even Steve Jobs was known to limit technology use for his children. Perhaps there’s real wisdom in that approach when it comes to protecting children’s health and development.