Our society is undergoing a pronounced aging of our population. With this shift there has been considerable research into what determines healthy aging.  One of the more important factors is minimizing the age-related loss of muscle mass. 

Muscle mass declines gradually after the age of 30-35 and accelerates after about age 50.  More advanced muscle loss with age is called sarcopenia. This loss of muscle mass

often parallels the decline in bone mineral density (BMD) and is termed osteosarcopenia. 

Declining muscle mass also drives greater loss of BMD.  During exercise, muscles produce as myokine or signaling factor, irisin, that helps to maintain BMD.

Bone undergoes ongoing remodeling to replace areas with wear related microcracks.  This process is performed by two different cells, osteoclasts which first remove the worn bone and osteoblasts which fill in new bone.  The activity of these two cells is held in balance by estrogen.  Estrogen gradually declines after age 35 years and declines more rapidly at perimenopause.  The result is greater osteoclastic activity/bone removal and less osteoblastic activity/bone replacement causing decreasing BMD.

Greater levels of irisin minimizes this age-related imbalance in osteoclastic and osteoblastic

activity reducing BMD loss.  Irisin both stimulates osteoblast activity and reduces osteoclast activity.

There are two important points to optimizing irisin levels to help maintain BMD.  The first is an individual’s muscle mass or the amount of this tissue available to produce irisin.  The second is stimulus to release muscle irisin, exercise.  Exercise enhances muscle production and release of irisin.  Exercise levels often decline with age, reducing the production and release of this important bone maintaining factor.

Key questions are:

• What type and level of exercise is needed to maintain muscle and its contribution to BMD?
• What else may help minimize age-related muscle loss?

A new study helped to answer the first question.  The study examined research on the relationship between aerobic exercise parameters and BMD. (1)  The study was a metanalysis, a type of study that looks at all of the studies on the topic and pools the data.  The parameters examined included:

• Exercise intensity
• Duration of each exercise session
• Duration of the exercise program
• Exercise frequency

Best outcomes with BMD came from:

• High intensity exercise versus moderate or low intensity
• Exercise session duration of 30-60 minutes
• Exercise program of at least 24 weeks
• Exercise frequency of 4-5 sessions per week.

Variations in these parameters such as shorter exercise sessions still produced some benefit but the parameters above resulted in the best gains in BMD.  Other studies have shown benefit from other exercise interventions.  One of the best suited exercises for older people may be vigorous walking for 45-60 minutes.  The benefit can be augmented by wearing a light-weight vest which increases the loading down through the spine and hips.

Other types of exercise can also be beneficial such as circuit weight training.  Higher speed contractions that load the spine and hips are most beneficial.  Less is understood about the frequency of circuit weight training, but sessions followed by a day of rest or alternative exercise such as aerobic exercise is perhaps ideal so muscle can recover.

Nutritional interventions have also been shown to be beneficial to osteosarcopenia improving both BMD and muscle. (2)  Feeding aging muscle helps to improve its performance which increases irisin levels which support bone. Two factors that help restore and maintain muscle (and thus bone) are protein and creatine.  Protein requirement for optimal muscle maintenance and repair is optimally 1.5 grams/kg of body weight.  That translates to 80 grams for a 120 lb. person and 110 grams for a 160 lb. person.

Putting the above figures into understandable terms for a 120 lb. person, for example, could get there with an 8 oz chicken breast (43 grams) at one meal and 8 oz salmon (40 grams) at another.  Many older adults may find that challenging and would do their best augmenting meals with a protein powder in a smoothie.  Whey protein is highest in the amino acid leucine which is perhaps the most crucial amino acid in muscle health.  Other sources such as pea protein or brown rice protein are options to those sensitive to dairy.

The second factor for muscle is creatine.  We generally produce about 1-2 grams of creatine per day, which muscle needs for energy, from sources such as meat and fish. This often diminishes with age, making supplementation helpful. Several studies have found that supplementing creatine enhances exercise benefits regarding muscle strength and endurance with aging. (3)  Optimal supplementation for older adults is 5 grams per day. 

Leucine is metabolized as beta-hydroxy-beta-methyl butyrate or HMB which is what muscle actually uses for repair.  The diagram shows the pathway by which leucine is converted to HMB.  As digestion and absorption of protein diminishes with age, it can be helpful to directly supplement with HMB daily.

The reality of healthy aging is that it takes more work than it did at age 30 years.  An important part of that work is supporting muscle which supports bone.  Fortunately, the science of the contribution of muscle to healthier aging is much better understood currently.  Putting that to work pays healthy dividends.

1. Zhou X, Yang N, Xi C, Ji J and Xu T.  A network meta-analysis of the effects of different aerobic exercise prescriptions on bone density in osteoporosis patients. Front. Endocrinol, 2026; 17:1828031.
2. Moreira-Velasco et al. Beyond Calcium and Vitamin D: Exploring Creatine, β-Hydroxy-β-methylbutyrate, Prebiotics and Probiotics in Osteosarcopenia. Nutrients. 2025; 17(14):2332.
3. Candow et al.  Effectiveness of Creatine Supplementation on Aging Muscle and Bone: Focus on Falls Prevention and Inflammation. J Clin Med. 2019 Apr 11;8(4):488.