During the third or fourth decade of one’s life, a strength decline occurs that is relatively consistent as the individual continues to age. Resistance training is an effective way to delay this process. It is essential for reducing limitations related to both functional tasks and activities of daily living, each taking place with aging. More details on resistance training will be discussed in a later section.
It is unclear surrounding the causes of age-related muscle loss, but it might be connected to hormonal changes, motor unit changes, or programmed cell death. Aging brings about a decrease in testosterone and growth hormone, which is possibly responsible for the loss of muscle mass, particularly in men. Over further time, the selective loss of type II motor units is a factor. A motor unit is composed of a motor neuron and the skeletal muscle fibres it activates. Often working together in groups, they coordinate the contractions of a single muscle. Type II motor units are referred to as the fast-twitch type, due to their quick response times. The selective loss of these results in a greater proportion of type I motor units and lower muscle mass and strength overall. This kind of motor unit develops a low peak force, which is sustained for relatively long periods of time.
The most popular explanation for age-related muscle loss is believed to be a consequence of programmed cell death. Caspases are enzymes responsible for breaking down and degrading proteins as well as DNA. Their activation and effect on DNA will alter the muscle’s ability to regenerate itself. These caspases can be initiated by some of the elements that are involved with muscle fatigue. Apoptosis-inducing factor also ties in with programmed cell death, and it has been shown to destabilize the nucleus, causing the cell impacted to die.
What is Sarcopenia?
Age-related loss in muscle mass and strength is known as sarcopenia. It affects adults under 70 years of age but is observed to a higher extent in adults over the age of 80 years. The decline in strength can vary, although it is more apparent regarding the lower body. This is troublesome because lower body functionality is crucial for maintaining one’s ability to perform actions of daily living (such as walking, rising from a chair, or using stairs).
Following age 30, each decade can cause up to a 3-5% reduction in an individual’s muscle mass, if they are physically inactive. Even in the case of an active lifestyle, some muscle loss will still be seen. No test exists or a specific level of decrease has been proposed that diagnoses sarcopenia. This is partly due to the understanding that loss of muscle to any degree is important to be aware of, as it influences strength and mobility. In addition, it plays a role in the likelihood of falls and fractures that older adults sometimes face. Symptoms of sarcopenia can manifest as weakness and loss of stamina, which may get in the way of exercise. If activity lessens though, muscle mass will decline further.
Physical activity is the main treatment for sarcopenia, especially in terms of strength training or resistance training. By using weights or resistance bands, these forms of exercise will help increase one’s muscle strength and endurance. Resistance training can support the health of an individual’s neuromuscular system and the function of their hormones. It can also enhance the conversion of protein into energy, in as little as two weeks, within an older adult’s body. The appropriate amount, intensity, and frequency of resistance training are significant elements to consider when planning workout routines. This is because what works well for one person might look different compared to someone else’s exercise patterns, and it is key for older adults to strive for the most benefit from their physical activity with the least risk of injury. Reaching out to an experienced trainer or physical therapist is recommended to create a personalized plan that is both suitable and motivating.
According to HealthLinkBC (linked here), the following is a collection of tips centred around resistance training for older adults:
- “Activities for healthy, strong muscles and bones should be done at least twice a week. Rest for at least 2 days between sessions.”
- “Do at least 8 to 10 exercises that include all the major muscle groups.”
- “Each exercise should be done for 10 to 15 repetitions. Repetitions are the number of times you do an activity (for instance, lifting a weight 8 times).”
- “Start with one set of each exercise. As you become stronger, do 2 sets. Rest for a minute between sets so your body has time to recover.”
- “A full-body activity session should take 20 to 30 minutes.”
Other sources of information for this article are WebMD, as well as Jennifer L. Kuk (Ph.D.), Michael Riddell (Ph.D.), and Angelo Belcastro (Ph.D.). Click here to read a related Amintro article, a great closer look at strength training for the older population.