Myth
To stay fit and healthy, mild exercise in the form of a short walk is sufficient for older adults; cardiovascular exercises or resistance training is not necessary.
Introduction
A popular belief among older adults is that a limited form of exercise, such as a short walk without the need for any resistance training or cardiovascular activities, is sufficient to lead a healthy and fit life. The aim of this article is to debunk misinformation and present recommendations on how to manage age-related physical and functional impairment.
What is Sarcopenia?
Sarcopenia is the loss of skeletal muscle mass with age, relating to functional impairment and physical disability, and loss of strength in older persons, particularly in the case of women. It is a potentially reversible cause of morbidity and mortality in older persons (Jannsen, 2002). Muscle weakness is an independent risk factor for high mortality in older adults. Muscle strength is a critical component in maintaining physical function, mobility, and vitality in old age (Goodpaster et al., 2006). Over the age span from 20 years to 80 years, there is approximately, a 30% reduction in muscle mass and a decline in cross-sectional area of about 20% due to a decline in both, muscle fiber size and number (Fielding et al., 2011).
Major factors that contribute to Sarcopenia are:
- Genetic Heritability
- Nutritional status (protein intake, energy intake, and vitamin D status)
- Physical activity
- Hormonal changes (declines in serum testosterone and growth hormone)
- Insulin resistance
Sarcopenia represents a major cause of disability and increased health costs in older persons. It is very common, but like most geriatric syndromes, seldom recognized by physicians (Fielding et al., 2011). No pharmacological treatment exists that can halt the progression of sarcopenia. Likewise, no pharmacological remedies are yet available to prevent the onset of age-related muscle wasting (Calvani, 2013).
Management of Sarcopenia
Older individuals have been shown to present muscle atrophy in conjunction with increased fat fraction in some muscles. The proportion of fat and connective tissue within the skeletal muscle can be estimated from axial B-mode ultrasound images using Echo Intensity (EI). EI was used to calculate the index of muscle quality of the rectus femoris and vastus lateralis of the mid-thigh. Walking, home-based weight-bearing resistance training, and its combinations are considered simple, easy, and practical exercise interventions for older adults. It was concluded that the EI of quadriceps femoris was decreased in both, but it was more in the case of the group with walking combined with resistance training. Thus, these results suggest that training-induced stimulation is associated with a decrease in EI in some thigh regions. Furthermore, the addition of home-based resistance training to walking would be effective for a greater reduction of EI (Yoshiko, 2018).
Strength-trained women increased their total muscle lean tissue cross-sectional area (CSA) of the thigh, quadriceps CSA, quadriceps lean tissue CSA, and the mean Hounsfield unit of the lower leg muscles. The change in quadriceps lean tissue CSA because of strength training was also significant compared with that in the endurance group. Intensive strength training can induce skeletal muscle hypertrophy in elderly women and thereby also reduce the relative amount of intramuscular fat, whereas the effects of endurance training are negligible. (Sipilä, 1985).
Along with resistance training, nutritional intervention can also be a measure for counter-measuring sarcopenia. Rather an adequate protein and energy intake together with physical exercise (resistance, aerobic, or their combination) has been indicated as the most effective strategy currently available to manage sarcopenia.
For a nutritional intervention to be effective against sarcopenia, it should –
- Provide an adequate caloric intake.
- Ensure the provision of appropriate nutrients, taking into account age, sex, metabolic profile, health status, and physical activity level.
- Provide the adequate quality and quantity of nutrients at the right time, that is when there is a physiological need.
- Be extended for a time sufficient to impact muscle health.
Specifically, a daily protein intake of 1g per kg has been identified as the minimum amount required to maintain muscle mass in old age. Amino acid composition of dietary protein is very important, especially Leucine. Also, it is mentioned that low doses of EAA (7g) gave poor response to muscle building in comparison with higher doses of EAA (10-15g) with at least 3g of Leucine. Beef meat, dairy products, whey, soybeans, cowpea, lentils, etc. should be preferred sources of protein by older adults as they have high EAA and higher Leucine. Older adults practicing resistance training may also be advised to ingest supplements of fast proteins (e.g., whey) or amino acids (e.g., leucine-enriched balanced EAA mix) immediately before or 2–3 hours after the training session to enhance exercise-induced muscle hypertrophy.
Consumption of food rich in vitamin D should be encouraged. Sun-dried mushrooms contain variable amounts of vitamin D2 (ergocalciferol). Foods fortified with vitamin D (both D2 and D3) are also available, such as milk, bread, some yogurts, and cheeses (Calvani et al., 2013).
Conclusion
Therefore, as with young adults, senior citizens also benefit significantly from a well-designed resistance training program in combination with nutritional support. While moderate-intensity cardiovascular activities (such as brisk walking) are helpful for the elderly, they may not be sufficient to prevent the loss of skeletal muscle mass.
References
1. Janssen, I., Heymsfield, S. B., & Ross, R. (2002). “Low relative skeletal muscle mass (sarcopenia) in older persons is associated with functional impairment and physical disability”, Journal of the American Geriatrics Society, 50(5), 889-896.
2. Fielding, R. A., Vellas, B., Evans, W. J., Bhasin, S., Morley, J. E., Newman, A. B., … & Zamboni, M. (2011). “Sarcopenia: an undiagnosed condition in older adults. Current consensus definition: prevalence, etiology, and consequences. International working group on sarcopenia”, Journal of the American Medical Directors Association, 12(4), 249-256.
3. Yoshiko, A., Tomita, A., Ando, R., Ogawa, M., Kondo, S., Saito, A., … & Akima, H. (2018). “Effects of 10-week walking and walking with home-based resistance training on muscle quality, muscle size, and physical functional tests in healthy older individuals”, European Review of Aging and Physical Activity, 15, 1-10.
4. Goodpaster, B. H., Park, S. W., Harris, T. B., Kritchevsky, S. B., Nevitt, M., Schwartz, A. V., … & Newman, A. B. (2006). “The loss of skeletal muscle strength, mass, and quality in older adults: the health, aging and body composition study”, The Journals of Gerontology Series A: Biological Sciences and Medical Sciences, 61(10), 1059-1064.
5. Sipilä, S., & Suominen, H. (1995). “Effects of strength and endurance training on thigh and leg muscle mass and composition in elderly women”, Journal of applied physiology, 78(1), 334-340.
6.Calvani, R., Miccheli, A., Landi, F., Bossola, M., Cesari, M., Leeuwenburgh, C., … & Marzetti, E. (2013). “Current nutritional recommendations and novel dietary strategies to manage sarcopenia”, The Journal of frailty & aging, 2(1), 38.
Author – Pratima Trivedi
