Star Trek's Mr Spock, who was characterised by his faith in science and logic would probably be happy with the twist on the Vulcan greeting of “Live long and prosper”, as it is based on sound science and it is a simple solution to a significant and worsening public health epidemic. Over recent decades as the average age of western populations has steadily risen, so too has the incidence of a wide range of illnesses and disorders. These include type II diabetes, respiratory issues, cardiac conditions, circulatory problems and a range of mental ill health issues. Researchers have understandably spent considerable time and resources investing some of the links between aging populations and increasing ill health burdens and one modifiable factor seems to relate to reduced muscle mass. It has been known for some time that a process called sarcopenia occurs as the body ages. Sarcopenia is an age related reduction in the volume of skeletal muscle with associated strength loss. Muscle strength declines in a linear fashion from around the age of 40 and by the 8th decade of life, 50% of the body's mature adult muscle mass may have vanished (1). This not only results in reduced strength and increased frailty, but it impacts on a number of metabolic systems with the result that the medical disorders listed above become more prevalent.
There are probably multiple factors which contribute to sarcopenia, but hormonal, dietary and physical issues are probably the most significant.
Reductions in testosterone levels have been identified as a cause of sarcopenia (2). Testosterone levels naturally reduce with age and don't need to be addressed with medical supplementation in the vast majority of cases. So in most scenarios this cause of sarcopenia is classed as non modifiable and for most people, isn’t an issue when it comes to implementing strategies to counter sarcopenic changes..
Building skeletal muscle requires sufficient dietary protein and the ability to metabolise it. It has been suggested that building muscle mass can best be achieved by combining strengthening exercises with a diet that supplies sufficient protein (3, 4).
A major reason for reducing amounts of muscle mass in older populations is simply a significant reduction in exercise. It’s a question of if you don’t use it, then you lose it. Reduced exercise and activity levels can of course be due to many factors. Feeling less energetic and developing painful joint conditions such as osteoarthritis are common reasons for people to reduce or give up exercise completely as they get older. The irony here is that regular exercise has been shown to reduce feelings of fatigue and strengthening exercises have been shown to be very effective at reducing chronic pain, including arthritis related joint pain (5, 6)
It is never too late to build muscle. The right type of exercise performed regularly can slow down or even reverse the effects of sarcopenia (7,8). The positive effects of regular strengthening exercises can bee seen in figure 1 which shows the cross sectional thigh muscle volume in 2 age matched 66 year olds with that of a 24 year old male. The summary of the average exercise levels of the 66 year olds is clearly reflected in their muscle volumes.
Health benefits of Strength Training
Strength training has been shown to reverse type II diabetes (along with an appropriate diet) (9) and can reduce hypertension (high blood pressure) (10). It is also associated with a reduction in a range of heart and lung disorders (11). Some of these improvements in cardiac health could be related to the positive changes that strengthening exercise has on blood lipid profiles (13, 14). If strength training was a drug, then it would be hailed as some kind of miracle cure as it has even been shown to be effective at improving mental health (15).
1 Walston J.D. “Sarcopenia in older adults” Current Opinion in Rheumatology. 24(6):623–627, Nov 2012
2 Shin MJ, et al. ”Testosterone and Sarcopenia” World J Mens Health. 2018 Sep;36(3):192-198
3 Martone A.M. et al. “Exercise and Protein Intake: A Synergistic Approach against Sarcopenia” BioMed Research International Vol 2017, Article ID 2672435
4 Phillips S.M. “Nutritional Supplements in Support of Resistance Exercise to Counter Age-Related Sarcopenia” Adv Nutr. 2015 Jul; 6(4): 452–460.
5 Hayden J.A. et.al. “Systematic review: strategies for using exercise therapy to improve outcomes in chronic low back pain.” Ann Intern Med. 2005 May 3;142(9):776-85.
6 Pelland L et. al. “Efficacy of strengthening exercises for osteoarthritis (Part I): A meta-analysis” Physical Therapy Reviews, Volume 9, 2004 - Issue 2
7 Michael McLeod M et. al. “Live strong and prosper: the importance of skeletal muscle strength for healthy ageing” Biogerontology. 2016; 17: 497–510.
8 Reid K.F. et. al. “Lower extremity power training in elderly subjects with mobility limitations: a randomized controlled trial” Aging Clin Exp Res. 2008 Aug;20(4):337-43.
9 Hagerman F. et. al. “Effects of high-intensity resistance training on untrained older men. I. Strength, cardiovascular, and metabolic responses” J Gerontol A Biol Sci Med Sci. 2000 Jul;55(7):B336-46.
10 Flack K.D. et al. “Aging, resistance training, and diabetes prevention.” J Aging Res. 2010 Dec 15;2011:127315.
11 Cornelissen V.A. “Effect of resistance training on resting blood pressure: a meta-analysis of randomized controlled trials” J Hypertens. 2005 Feb;23(2):251-9.
12 Shaw B.S. et al “Resistance exercise is medicine: Strength training in health promotion and rehabilitation” International Journal of Therapy and Rehabilitation 22(8):385-389 · August 2015
13 Kelley GA. et. al. “Boyden T.W. et al “Resistance exercise training is associated with decreases in serum low-density lipoprotein cholesterol levels in premenopausal women”. Arch Intern Med. 1993 Jan 11;153(1):97-100.
14 Kelley GA. et al. “Impact of progressive resistance training on lipids and lipoproteins in adults: a meta-analysis of randomized controlled trials”. Prev Med. 2009 Jan;48(1):9-19
15 O’Connor P. J. et. al. “Mental Health Benefits of Strength Training in Adults”. American Journal of Lifestyle Medicine, 2010 4(5), 377–396.
16 Gordon B.R. et. al. “The Effects of Resistance Exercise Training on Anxiety: A Meta-Analysis and Meta-Regression Analysis of Randomized Controlled Trials.” Sports Med. 2017 Dec;47(12):2521-2532