When I think of bones, I envision the massive skeletons on exhibit at the Museum of Natural History in Chicago. These unbreakable bones supported large, muscular animals weighing over 10,000 pounds. In sharp contrast to these prehistoric bones is the skeleton of the average adult. The human skeletal system is nearly fully developed by age 20 and begins demineralizing (i.e., weakening) in our late 30's early 40's. Bone loss continues at a rate of up to 1 percent per year for all of us. However, during and after menopause, women lose bone at 2 percent per year.
While breaking a bone is medically significant, it can be catastrophic later in life. Given that we live longer, fractures of the hip and spine have become increasingly common in the United States. Most people are surprised to hear osteoporosis kills more women than breast cancer.[1] Surviving a hip fracture can often be the first stage of failure. Half of all women who fracture a hip will never walk again unaided (i.e., without using a cane or walker), while 20% will die within one year! Despite advances in the treatment of osteoporosis, most therapies focus on slowing the rate of bone resorption (i.e., bone breakdown) while nearly ignoring the bone-building process. Here's what you should know to avoid life-threatening fractures.
In the late 1800s, a discovery by German anatomist and surgeon Julius Wolff changed how we think about bones forever. Dr. Wolff's work revealed a link between muscle strength and bone density, known as Wolff's Law [2]. According to Wolff's Law, bones adapt to the stress placed on them. When you train your muscles, the muscles impose stress on your bones, and your bones respond to this stress by becoming stronger and healthier. Therefore, your strength workout is a bone-building workout. If you want strong bones, strengthen your muscles.
Building stronger muscles require Strength Training. While some activities use your muscles (i.e., running, walking, biking, swimming, etc.), only Strength Training strengthens them. Strength Training is also the safest way to stimulate specialized bone-building cells within your skeleton called osteoblasts. While osteoblasts activate with high-force activities like running and jumping, these activities are typically too risky for older adults with low bone mass. Activities that generate high-ground reaction forces can easily exceed the fracture threshold (i.e., the point where a bone fractures). On the other hand, Strength Training generates no ground reaction force, meaning it's a safe way to increase strength and bone health.
The benefits of Strength Training go beyond building bones. While strong bones are essential, reducing fall risk is crucial. Strength Training is a proven way to prevent falls [3]. It helps by strengthening balance muscles in the spine and lower body and improving coordination. As you age, you lose balance and coordination. Reversing this process decreases the likelihood you will fall. However, Strength Training also increases fall survival rates. If you fall, you are less likely to experience a fracture due to the increased bone mineral density and protective muscle you have built around your joints. My 85-year-old mother is a good example. Earlier this year, she fell in the middle of the night and survived with only a nasty bruise. Thankfully, she's been Strength Training at MEDFITNESS.
Having worked with thousands of clients over the past four decades, I can tell you that supervised strength workouts are safer, more effective, and more likely to occur. The structure and accountability that supervision provides are what make the difference. A landmark 2017 study published in BioMed Research International measured the effects of supervised Strength Training against unsupervised Strength Training [4]. After six months of supervision, researchers reported health benefits in the supervision group. However, unsupervised Strength Training provided no health benefits. The authors attribute the lack of benefits to the reduced effort common in unsupervised workouts.
Your muscles are 95 percent water and protein; insufficient water intake can leave them dehydrated and underperforming. Dehydration can also contribute to lightheadedness, increasing your risk of falling. The National Academy of Sciences, Engineering, and Medicine recommends fifteen cups of liquids per day for men and eleven cups for women [5]. These recommendations include all fluids (i.e., water, tea, coffee, tomato juice) and food. A healthy diet centered around whole foods can provide up to 30 percent of daily fluids. Water is ideal because it is calorie-free and readily available. I start each day with a large glass of water and track my daily water intake – this keeps my muscles hydrated and performing at their best.
Consuming adequate protein is necessary to optimize the muscle-building effects of Strength Training. However, older adults may require more protein than younger adults due to the decreased sensitivity of muscle to protein (i.e., anabolic resistance) [6]. There is growing evidence that the Recommended Dietary Allowance (RDA) for protein does not support optimal health in older adults. The PROT-AGE Study Group, an international group commissioned to study protein needs with aging, recommends 1.0 to 1.2 grams of protein per kilogram of body weight per day [7]. This group has also recommended 25 to 30 grams of protein per meal to offset anabolic resistance. In the end, osteoporosis can be optional! Strength Training can support bone health when combined with adequate fluids and protein.
If you or someone you know is interested in a Free Trial Workout, please send them our way! Send your inquiries HERE to schedule a Free Trial Workout and start living your best life.
Stay Strong,
Richard J. Wolff, RDN
References
1. Crowley C., Lodge H. 2016. Younger Next Year. New York, NY. Workman Publishing Co., Inc.
2. Wolff's Law: An Overview for Clinicians. https://pubmed.ncbi.nlm.nih.gov/8060014/
3. Guidelines for Exercise Testing and Prescription. ACSM, Tenth Edition, 2018.
4. BioMed Research International. Volume 2017, Article ID 2541090, 14 pages. https://doi.org/10.1155/2017/2541090
5. https://www.mayoclinic.org/healthy-lifestyle/nutrition-and-healthy-eating/in-depth/water/art-20044256
6. Journals of Gerontology, Series A: Biological Sciences and Medical Sciences. 2015;70(1):57-62.
PROT-AGE Study Group. J Am Med Dir Assoc. 2013:149(8):542-