WHAT EXACTLY IS SARCOPENIA?
“Sarcopenia is the age-related loss of muscle mass, strength and/or physical performance, which can lead to weakness, slower mobility, metabolic problems and increased risk of falls,” explained Associate Professor Reshma Merchant, the head and a senior consultant with National University of Singapore’s Division of Geriatric Medicine, Department of Medicine.
The muscle loss that Assoc Prof Merchant referred to affects your skeletal muscle, the type of muscle that attaches to the bones and is responsible for movement and posture – or letting you catch the bus and preventing you from tripping when you miss a step. (There are two other primary types of muscles: Cardiac muscle in the heart and smooth muscle that line the walls of internal organs such as the intestines and blood vessels.)
“Skeletal muscle is the largest endocrine organ in the body, comprising about 40 per cent of our body mass,” said Assoc Prof Merchant. This means that losing your skeletal muscle can affect your basal metabolic rate (how many calories you burn at rest), insulin sensitivity and how effectively your body uses glucose. In other words, muscle loss is not just about movement and balance but also the middle-age spread and metabolically linked diseases such as diabetes, cardiovascular disease and fatty liver.
Much like your bones, your skeletal muscle is constantly broken down and rebuilt. In fact, it undergoes protein turnover at roughly 1.5 per cent each day, according to Assoc Prof Merchant. Muscle loss occurs when muscle protein breakdown (MPB) consistently exceeds muscle protein synthesis (MPS), leading to sarcopenia.
All is well and good in your younger days when your body is able to keep muscle protein synthesis ahead of muscle protein breakdown.
But with age comes a stumbling block in the form of anabolic resistance. This is when “the body shows a blunted MPS response to protein intake and regular exercise, making it harder to gain or maintain muscle mass”, explained Assoc Prof Merchant. In men, anabolic resistance commonly emerges between mid-40s and early 50s; in women, during perimenopause, she added.
WHY SHOULD YOU BE CONCERNED ABOUT SARCOPENIA?
You want to reduce your risk of falling in your senior years, which is the top factor for admission at the A&E among geriatric patients, said Lim. What are very likely to result are fractures of the spine, wrist, elbow and particularly hip, as well as head injuries, reduced mobility and long-term admissions, he said.
Fear from a previous fall can also lead to anxiety, self-imposed activity restriction, social isolation, depression and a reduced quality of life, Lim pointed out. “Eventually, the senior becomes inactive, resulting in even weaker muscles and a never-ending cycle of recurrent falls.”
Lim said: “It is always easier to maintain muscle function than trying to get back it back after it’s lost”. Physiological changes that occur with age can also limit the effectiveness of your fitness training programme, reminded Lim. “These include a slower metabolism, hormonal changes, reduced flexibility, decreased coordination and reflexes, as well as diminished nerve function – all of which can contribute to slower recovery and lower peak heart rates.”
But all is not lost for seniors. “Many studies have indicated that the potential to regain muscle is not lost, even in old age, when the training programme is appropriate,” said Lim. “Some research even shows no significant difference in muscle mass gain between young and older adults as long as they follow a consistent regime at a moderate intensity.”
