Healthy bones are the foundation to healthy running. Bones are strong, sturdy, and designed to tolerate a great amount of stress. In fact, bones get stronger from weight bearing. This is good news for runners, who put cumulative stress through their bones with each foot fall.
However, bones have their limits and require proper care. Here are key things all runners should know about their bone health.
Energy availability is a pillar of bone health. Energy availability (EA) is a measure of energy burned versus energy replenished per day. You have to eat enough calories to not only support the miles you put in, but to support your brain and bodily functions. If EA is chronically low from underfueling or overtraining, your body will start to drain your bones to get the nutrients it needs to keep you alive and moving. If you’re underfueling or overtraining, bones become weaker. EA can be quantified with this calculator (www.femaleathletetriad.org/calculators). Daily EA should be around 45 kcal/kg FFM/day and athletes should be eating a MINIMUM of 30 kcal/FFM/day for optimal bone health. Along with weaker bones, low EA can lead to fatigue, decreased performance, and increased risk of injury.
Sleep is by far the most important aspect of recovery an athlete can utilize, as lack of sleep is associated with weakened bones. Sleep deprivation can have significant negative effects on performance in endurance tasks and may also influence learning, memory, pain perception, cognition, immunity and inflammation. In a study of military recruits who were purposefully sleep deprived, it was found that they had a 5% reduction in bone mineral density in just seven days.1 Sleep is the time your body takes to replenish and repair tissue that was stressed during the day. If your sleep is disturbed, your bones are at a greater risk of injury.
Nutrition is about quality and quantity. Runners need to eat enough food each day. (Remember EA?). Some runners find benefit in an individualized consultation with a registered dietician. (We can recommend some good ones!) Specifically, all runners should pay attention to daily calcium intake. Calcium is a major building block that keeps bones strong. Recent studies show that women who consumed less than 800 mg of calcium per day had nearly 6 times the rate of stress fracture than women who consumed more than 1500 mg of calcium.2 Furthermore, fracture risk in runners is decreased by 62% for every additional cup of skim milk consumed per day.2 Calcium’s best friend, Vitamin D, is responsible for calcium absorption. The worse a runner’s vitamin D intake, the longer it takes to recover from stress fracture.3 Thus, increasing daily calcium and vitamin D is a simple way to reduce fracture risk.
Listen up, ladies. Your menstrual cycle is a vital sign. That’s right: put it right up there with heart rate and blood pressure. A healthy, regular cycle is the cardinal sign that you are maintaining an appropriate EA, getting adequate nutrition, and protecting your bones. Female runners who have stopped menstruating are at a 4.5-fold increased risk of injury compared to regularly menstruating women.4 This is because monthly estrogen spikes with each cycle help protect bones against break down. Your period is a monthly signal of your health. If your periods become irregular or stop, talk to your healthcare provider for strategies to regain your cycle.
When it comes to bone health, prevention of fractures is best. If a fracture does happen, the road to recovery doesn’t have to be so bumpy when you’re armed with the right information to help prevent future bone health issues. Most importantly, the road ahead has the potential to be better than before. If you have questions about bone health or would like to be evaluated for a bone stress injury, don’t hesitate to reach out to our therapists.
- Ben-Sasson, et al. Extended duration of vertical position might impair bone metabolism. Eur J Clin Invest, 1994
- Nieves et al. Nutritional Factors That Influence Change in Bone Density and Stress Fracture Risk Among Young Female Cross-Country Runners
- Serum Vitamin D Levels Are Inversely Associated With Time Lost to Bone Stress Injury in a Cohort of NCAA Division I Distance Runners
- Heikura I. 2018