What happens to muscle mass as you age?

After the age of 30, you gradually start losing muscle mass and it becomes important to find ways to retain or build optimal muscle mass. Loss of muscle mass can have a significant impact on your quality of life as you get older.

If left unchecked, reduced muscle mass can lead to an increased risk of reduced mobility and independence, frailty and falls, self-confidence and chronic diseases¹. Muscle mass is not only associated with strength, mobility and physicality. Muscle mass increases your metabolism, providing you with energy and helping you burn fat, whilst reducing your risk of metabolic conditions, such as insulin resistance and Type 2 Diabetes.

Sarcopenia is the medical term for loss of muscle mass, strength and function and is usually associated with age. Typically, the loss of muscle mass picks up pace after the age of 75. However, this can vary depending on factors such as genetics, lifestyle and dietary behaviours.

Physically, loss of muscle tone and definition indicates sarcopenia, but over time you will notice a decline in strength, stamina, balance and energy levels. What you could easily do in your 20s and 30s becomes more of a concerted effort.

What causes sarcopenia?

The cause of sarcopenia is not well understood but is thought to be the result of several changes that occur as you age. Hormone levels, physical activity and nutrition contribute to this condition.

At the cellular level, the contributing factors include a reduction in the number of muscle cells. Muscle contraction time and force is reduced, and this is likely associated with a reduction in muscle cells and in the cellular components that store and pump calcium into the cells to support this process². The total number of muscle fibres declines as you age, but also the distribution of muscle fibres changes, with an increased proportion of type 1 (slow twitch) fibres compared to type 2 (fast twitch) fibres³.

Testosterone and growth hormone levels influence muscle mass and strength. As men get older, the amount of testosterone production reduces, and levels start to fall from around the age of 40. Although oestrogen and progesterone levels are the focus of hormonal changes in women at menopause, women also produce androgen hormones, such as testosterone. The decline of oestrogen is associated with reduced bone density, but it is not linked to reduced muscle mass. Like men, women’s muscle mass is influenced, albeit to a lesser degree, by testosterone³.

Physical activity and appetite levels often decrease as you age and can be a contributor to sarcopenia. Physical activity levels generally decline as you age, and older adults may have less energy or motivation to cook, and this can lead to malnutrition. Nutrients such as protein, vitamin D and calcium are needed to build healthy muscles. As you age, the body’s ability to synthesis vitamin D and utilise protein can become impaired, compounding the impact of nutrition and activity levels.

What can you do maintain muscle mass?

Aging is influenced by your dietary and lifestyle behaviours, and introducing healthy behaviours can positively influence muscle mass and strength:

• Strength and resistance training – there are many options to choose from and this can vary from using weights to using your own body weight. Swimming, yoga, and walking are all good options, which can be enjoyed at any age.

• Nutrition – when it comes to protein, it is important to choose high quality protein from lean meat, or a combination of plant proteins. The recommended intake of protein varies from 0.8 to 1.8 grams per kg of your body weight, depending on your activity levels, age and whether you are looking to maintain or build muscle. A person weighing 70kgs would be aiming for between 56 and 126 grams of protein. Sardines, almonds, and green leafy vegetables are all great sources of calcium.

• Sunlight – as little as 15 minutes of daily exposure to direct sunlight is sufficient for healthy vitamin D levels. This should be balanced with protecting your skin and, so it is recommended to get your sun exposure before 10am or after 3pm.

• Supplements – as your skin ages and your body becomes less capable of utilising protein from sun exposure and diet alone, supplementation is needed to support healthy levels of protein and vitamin D in the body. Supplements such as HMB and vitamin D are helpful to support healthy muscles. You can read more about HMB here.

 

Suzy Walsh 

BBA (Hons)., BNat., mNMHNZ

Registered Naturopath & Medical Herbalist

References:

¹ Wilkinson, D., Piasecki, M., & Atherton, P. (2018). The age-related loss of skeletal muscle mass and function: Measurement and physiology of muscle fibre atrophy and muscle fibre loss in humans. Ageing Research Reviews, 47, 123-132. doi:10.1016/j.arr.2018.07.005

² Volpi, E., Nazemi, R., & Fujita, S. (2004). Muscle tissue changes with aging. Current Opinion in Clinical Nutrition and Metabolic Care, 7(4), 405-410. doi:10.1097/01.mco.0000134362.76653.b2

³ Siparsky, P. N., Kirkendall, D. T., & Garrett, W. E. (2013). Muscle changes in aging. Sports Health: A Multidisciplinary Approach, 6(1), 36-40. doi: 10.117/1941738113502296