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TV and Video Games Can Lead to Weaker Bones

July 10, 2015

Story at-a-glance

  • Among boys aged 15 to 19 years old, the longer the time spent in front of screens, the lower their bone mineral density measured
  • Excessive use of electronics takes away many opportunities to engage in weight-bearing activities, which is key for building strong bones
  • Peak bone mass achieved during childhood and adolescence is one of the major factors that can either contribute to, or help prevent, osteoporosis later in life

By Dr. Mercola

Teenage boys who spend too much time playing video games, watching movies, and surfing the Web could be putting their bone health at risk. It should come as no surprise that good bone health in your later years begins in your youth, during your childhood and adolescence, as this is when skeletal growth is at its peak.

This time of bone development sets the stage for what's to come. Peak bone mass during childhood and adolescence is one of the major factors that can either contribute to, or help prevent, osteoporosis down the road, so it makes sense to pay attention to building strong and healthy bones during the early years.

Unfortunately, the average US teen girl spends about 5.5 hours a day on "screen time" (computers, television, video games, smartphones, tablets, etc.), while boys spend about 6.5 hours a day.

This excessive use of electronics not only sets kids up for the perils of too much sitting, it takes away many opportunities to engage in weight-bearing activities, which is key for building strong bones.

Screen Time Linked to Weaker Bones in Teen Boys

Among boys aged 15 to 19 years old, the longer the time spent in front of screens, the lower their bone mineral density measured. Boys who spent excessive time on screen-based sedentary activities also tended to weigh more than their peers who used them for 1.5 hours a day or less.

Walking, running, and engaging in other weight-bearing activities leads to stronger, denser bones. Lack of activity may cause weak bones and even osteoporosis. Dr. Anne Winther of the Arctic University of Norway told the Daily Mail:

"Bone mineral density is a strong predictor of future fracture risk… The findings for boys… clearly show that sedentary lifestyles during adolescence can impact… [bone density] and thus compromise the acquisition of peak bone mass. This can have a negative impact in terms of osteoporosis and fracture risk later in life."

Curiously, girls did not experience the same weakening effect on their bones and, instead, had higher bone mineral density with increasing screen time. The researchers aren't entirely sure what's causing this conundrum.

It could be because girls tend to engage in other activities (like crafts or hobbies) while using screens or due to the fact that they tend to mature earlier, which means their bone health may have been less malleable at the ages assessed in the study. Dr. Laura Bachrach, a pediatric endocrinologist at Stanford University Medical School in California, told Reuters:

"We're really worried about this because there's sort of this critical time between being born and reaching the early 20s when you're setting up the scaffolding of life (in terms of the geometry and density of the bone).

…You sort of max out in your early 20s and there is real concern that the lifestyle of young people nowadays versus 40 or 50 years ago is setting people up to be more at risk as adults for not having a very robust bone bank as they age."

Physical Activity as a Child Leads to Stronger Bones

Whereas spending too much time being sedentary is associated with lower bone mineral density in boys, staying physically active during childhood can help promote strong bones throughout your life.

Your bones are constantly being rebuilt in a dynamic process involving the removal of old bone through osteoclasts and regeneration of new, healthy bone by osteoblasts.

Weight-bearing exercise works to build stronger bones by stimulating cells responsible for the synthesis and mineralization of bone (osteoblasts). As you put more tension on your muscles it puts more pressure on your bones, which then respond by continuously creating fresh, new bone.

The youth have a unique opportunity to impact the future health of their bones by staying active during their childhood. Researchers found that boys and girls who were the most active throughout their lives (starting at age five) had denser bones and better bone shape than less active participants at the age of 17.

Unfortunately, the study found that most children and teens are not active enough to take full advantage of these formative bone-building years, especially as they got older.

On average, girls spent just 47 minutes being active each day during childhood, and this decreased to 24 minutes a day at age 17. Boys' activity levels fell from 60-65 minutes a day during childhood to 36 minutes a day as teens.

The key is to get your child interested in physical activity at a young age; even when activity decreased during the teenage years, children who had been more active in childhood still had better bones.

Mechanical loading – running and jumping, as opposed to swimming or biking -- is one of the best strategies to help your kids build excellent bone mass early on, and these are the types of activities that occur naturally (and frequently) during free play.

Early-Life Activity Makes Your Bones Stronger at Age 90…

Taking advantage of young children's natural desire to run, jump and climb by installing a playground in your backyard or taking regular trips to your neighborhood park are investments in your child's bone health that will last a lifetime – literally. As reported in the Journal of Musculoskeletal & Neuronal Interactions:

"The young skeleton shows greatest plasticity to physical activity-related mechanical loads, but bones are most at risk of failure later in life. The discrepancy raises the question of whether the skeletal benefits of physical activity completed when young persist with aging."

It turns out, they do. After analyzing the bone differences in the throwing and non-throwing arms of major league baseball players at different times in their life, and comparing them to differences in non-baseball players.

The researchers found that exercise when you're young leads to stronger bones, with the benefits persisting during aging, even into your 90s.

Specifically, half of the bone size and one-third of the bone strength built up by early-life physical activity were retained throughout life.

Physical activity during youth, in other words, provides lifelong benefits to your bone size and strength. Lead researcher Stuart Warden, an associate professor at Indiana University-Purdue University Indianapolis, said:

"Exercise during youth adds extra layers to the outer surface of a bone to essentially make the bone bigger. This gives you more 'bang for the buck,' as the addition of a small amount of new material to the outside of a bone results in a disproportionate increase in bone strength relative to the gain in mass."

The Risks of Being Sedentary Extend Far Beyond Your Bone Health


When you combine screen times with hours spent behind desks at school, the average US child is spending far too much time sitting. This poses a risk to growing bones, yes, but it also presents body-wide risks that may contribute to obesity and growing rates of chronic disease in both childhood and adulthood.

For instance, excessive sitting significantly impacts your cardiovascular and metabolic function. This raises your risk for heart attack, type 2 diabetes, insomnia, arthritis, and certain types of cancer—and that's just the tip of the iceberg. Sitting for extended periods of time increases your risk for premature death. This is especially concerning given the fact that you may be vulnerable to these risks even if you exercise regularly.

An hour of physical activity a day simply cannot counteract the ill effects of too much sitting. If your child spends a lot of time in front of an electronic screen, his or her mental health may also be at risk. In one UK study, excessive screen time produced negative effects on children's self-worth, self-esteem and level of self-reported happiness.

The children who spent four hours or more on computer gaming reported lower levels of well-being than their peers who spent less time on this activity. Children spending more time in front of computer screens also experience more emotional distress, anxiety, depression, and behavioral difficulties.

To combat this problem, some forward-thinking schools are giving children more opportunity to move around throughout the day, rather than expecting them to sit for hours in desks (a rather unnatural feat for a child). For instance, at Vallecito Elementary School in San Rafael, California, four classes have introduced chair-less standing desks.

After an initial adjustment period, the standing desks have been met with rave reviews. The students report the desks are "fun" and help them feel "more focused." Teachers say the desks make children more attentive and parents say their kids are sleeping better at night… all while avoiding the risks of excessive sitting time; a win-win situation all around!

Do You Need Help Getting Your Child Active?

Unless your child is seriously overweight or obese (in which case he may benefit from seeing a personal trainer who specializes in children), you shouldn't expect him or her to log in 30 minutes on the treadmill or elliptical machine. The trick to getting kids interested in exercise at a young age is to keep it fun, not feeling like a chore. Encourage your children to engage in activities that are naturally interesting to them, such as playing on the monkey bars, rollerblading, skateboarding, dancing, playing basketball with friends, hopscotch, jumping rope, or even helping you in the garden.

Organized sports – soccer, gymnastics, softball, and basketball -- are great, but so are spontaneous romps through mud puddles, climbing trees, and making snow angels. Resist the urge to overly structure your child's "exercise time," instead encouraging natural active play. Toward this end, allow your kids to exercise in bursts throughout the day -- a game of tag here, a bike ride there -- so they don't feel pressured or like they're being "punished." It's also imperative that you act as a role model by staying active yourself. If your kids see you embracing exercise in a positive way, they will naturally follow suit.

5 More Tips to Optimize Your Bone Health

Exercise is, without a doubt, crucial for optimal bone health, but the following guidelines can also help you maintain, or increase, your bone strength safely and naturally at any age:

  1. Make your own fermented vegetables using a special vitamin K2-producing starter culture, or supplementing with vitamin K2 if you're not getting enough from food alone. Vitamin K2 serves as the biological "glue" that helps plug the calcium into your bone matrix. Also remember to balance your calcium and magnesium (1:1 ratio). Vitamin K2 is produced by certain bacteria, so the primary food source of vitamin K2 is fermented foods such as natto, a fermented soy product typically sold in Asian grocery stores. Fermented vegetables can be a great source of vitamin K if you ferment your own using a specially designed vitamin K2-rich starter culture.
  2. Please note that not every strain of bacteria makes K2, so not all fermented foods will contain it. For example, most yogurts have almost no vitamin K2. Certain types of cheeses, such as Gouda, Brie, and Edam, are high in K2 while others are not. It really depends on the specific bacteria. Still, it's quite difficult to get enough vitamin K2 from your diet—especially if you do not eat K2-rich fermented foods—so taking a supplement may be a wise move for most people.

  3. Avoid processed foods and soda, which can increase bone damage by depleting your bones of calcium. By ditching processed foods, you're also automatically eliminating a major source of refined sugars and processed fructose, which drive insulin resistance. It will also provide you with a more appropriate potassium-to-sodium ratio, which is important for maintaining bone mass.
  4. Increase your consumption of raw, fresh vegetables, ideally organic. If you find it difficult to eat the recommended amount of vegetables you need daily, you can try vegetable juicing.
  5. Optimize your vitamin D levels, ideally from appropriate sun exposure or a high-quality tanning bed. Vitamin D builds your bone density by helping your body absorb calcium. If you use an oral supplement, make sure you're using vitamin D3 (not D2), and that you're also increasing your vitamin K2 intake and monitoring your levels for safety.
  6. Maintain a healthy balance between omega-6 and omega-3 fats in your diet by taking a high-quality animal-based omega-3 supplement like krill oil and reducing your consumption of processed omega-6, found in processed foods and vegetable oils.
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