I recently listened to a webinar hosted by the Canadian Longitudinal Study on Aging. Dr. Russell Hepple is the director of McGill Research Centre for Physical Activity and Health. Dr. Hepple did a great job discussing age-related changes to muscle, how this is different in master athletes and links to cognitive function, which I’ve summarized below.
Muscle changes with age
As we age, our muscle mass decreases and is replaced with connective tissue and fat. All muscle fibres atrophy as we age, leading to decreased mobility, ADL ability and coordination.
Some of this is due to not just muscle fibre atrophy, but the replacement of lost muscle fibres with angular muscle fibres. These denervated muscle fibres drive muscle atrophy and lead to decreased stability in the neuromuscular junction. “Denervation” is the interruption of nerve function AND “The neuromuscular junction” is the connection between the nervous system and muscular system (i.e. motor neuron talks to muscle fibre).
We not only see a decrease in muscle mass, and changes to muscle fibres, but also a loss of motor units themselves. Motor units are “systems” in the muscle that comprise a motor neuron and all the muscle fibres it innervates (it was we were measuring in the latest Parkinson’s research project I was involved in! pics HERE). As we age, we see a progressive deterioration, about 1/3 loss between 27 and 66 years, and another 1/3 loss between 66 and 82 years. This leads to changes in coordination and activation patterns of the muscle and changes to the muscle itself (i.e. sarcopenia). Dr. Hepple mentioned that in your 60’s is a critical year to build muscle mass before accelerated age-related declines set in.
But, does everyone age at the same rate?
NO, there are different ways in which we age!
Look at Nancy Reagan, compared to master athlete Olga Kotelko – both 92yrs old.
And, what about Ed Winlocks? He is a marathoner who completed the TO marathon in 3:15.54 in 2011, a record in the 80+years category!
What allows Ed and Olga to maintain impressive athletic ability and age optimally?
In a study looking at 80yr old master athletes, Dr. Hepple found preservation of: maxVO2 (similar to persons 60years younger!), number of muscle mitochondria, number of motor units and preserved muscle fibre size and type.
Balance is also preserved in master athletes, which is important since balance tests take into consideration proprioception, coordination and functions in the cerebellum; representing integrative measure of the entire neuromuscular system. This is a relevant finding highlighting the importance of balance! (*cough *cough … balance is improved with yoga!)
Linking muscle and brain function as we age
Physical fitness is also important because physical frailty parallels cognitive impairment (Boyle et al. 2010). Linking how we age in our bodies with how we age in our brains! Master atheletes show increase verbal and learning memory, cognitive processing speed, and may suggest protection of temporal and frontal lobes (regions of the brain succeptible to aging!); preservation of both muscle and brain health!
BDNF may be link between preservation brain and muscle function. BDNF responds to muscle contraction and (what does it do in the brain). See more on what BDNF is and how it relates to brain function and exercise in a previous post HERE.
Great information, not only implications for our ability to climb stairs, but complete the Sunday crosswords too! Much love.