One of the many benefits of exercise is that exercise is good for your bones. But are all types of exercise beneficial?
Many factors determine bone health including (but not limited to) genetics, nutritional status, exercise activity (with bone weight), macro and micronutrient intake, hormonal status, chronic inflammation, and medication use.
It is generally accepted that bone-loading (weight-bearing) activities increase bone formation through the activation of certain cells in bone called osteocytes, which serve as mechanosensors and sense bone loading. Osteocytes produce a hormone called sclerostin, which normally inhibits bone formation. When osteocytes sense bone-loading activities, sclerostin secretion decreases, allowing increased bone formation.
Investigators in Canada have demonstrated greater increases in bone density and strength in schoolchildren who engage in moderate to vigorous physical activity, particularly bone-loading exercise, during the school day compared to those who do not. this.
In females, normal estrogen levels appear to be necessary for osteocytes to exert these effects after bone-loading activities. This is probably one of several reasons why female athletes who miss their periods (an indicator of low estrogen levels) and develop low bone density with an increased risk of fractures even when they are still at a normal weight.
A concern about prescribing bone-loading activity or exercise for people with osteoporosis is that it would increase the risk of fractures from impacting fragile bones. Safe bone loading rates for brittle bones can be difficult to determine.
In addition, excessive exercise can worsen bone health by causing weight loss or loss of periods in women. Very careful monitoring may be necessary to ensure that energy burned is balanced with food consumed. Therefore, the nature and volume of exercise should ideally be discussed with a health care provider or physical therapist, as well as a dietitian.
In patients with osteoporosis, high-impact activities such as jumping or repetitive high-impact activities such as running or jogging, and even bending and twisting activities such as toe-tapping, golf, tennis, and bowling may not be recommended because they increase the risk for fracture. .
Yoga poses should also be discussed, because some may increase the risk for compression fractures of the vertebrae in the spine.
Strength and resistance training is generally believed to be good for bones. Strength training involves activities that build strength and muscle mass. Resistance training builds muscle strength, mass and endurance by making the muscles work against some form of resistance. Such activities include weight training with free weights or weight machines, using resistance bands, and using your own body to strengthen major muscle groups, such as push-ups, squats, lunges, and planks.
A certain amount of aerobic weight-bearing exercise is also recommended, including walking, low-impact aerobics, the elliptical, and stair climbing. But non-weight-bearing activities, such as swimming and cycling, usually do not improve bone density.
In older individuals with osteoporosis, agility exercises are particularly helpful in reducing the risk of falling. These can be structured to improve hand-eye coordination, foot-eye coordination, static and dynamic balance and reaction time. Agility exercises with resistance training may help improve bone density in older women.
An optimal exercise regimen includes a combination of strength and resistance training, aerobic weight training, and exercises that build flexibility, stability, and balance. A physiotherapist or trainer with expertise in the correct combination of exercises should be consulted to ensure optimal effects on bones and overall health.
In those who are at risk for overtraining to the point that they begin to lose weight or miss their periods, and certainly in all women with disordered eating patterns, a dietitian should be part of the decision-making team for ensuring that energy balance is maintained. In this group, especially very underweight women with eating disorders, physical activity is often limited until they reach a healthier weight and ideally after menstruation resumes in premenopausal women.
Bone density can be assessed at intervals using dual-energy X-ray absorptiometry where there are concerns about osteopenia or osteoporosis.
With adequate counseling and follow-up, it is likely that any person at risk for bone density loss can benefit from an appropriate exercise program.
