We hear time and time again that we lose strength as we age, but why is this? Why is common to see older people look more frail, less muscular, and, dare I say…. a bit wilted?
As we grow older, our skeletal muscles tend to wither and weaken, a phenomenon known as sarcopenia. Strength peaks around 25 years of age, plateaus through 35 or 40 years of age with sarcopenia appearing at around age 40. We continue to lose strength and muscle with 25% loss of peak force by the age of 65? Why?
Several factors account for why we lose strength
One reason is that muscle accumulates more fatty tissue with age. If you were to look at the muscles from an older person, you’d see that it has significantly more fat and connective tissue as the muscle of a youthful person. What causes this? Studies show that this change is partially brought on by hormonal changes including the decrease of testosterone, estrogen and the increase of the stress hormone called cortisol.
Another reason why we lose strength has to do with the reduction of fast-twitch muscle fibers. Muscles are made up of 2 types: fast-twitch & slow-twitch muscle fibers. Slow-twitch fibers are often called endurance fibers. Interestingly, they are resistant to fatigue and they do NOT require a lot of force to contract. These are the fibers you mainly use when you walk or do a high number of reps with light weights.
Fast-twitch muscle fibers, conversely, fatigue quickly but contract with more force. They are the speed and power fibers, the ones you recruit when you sprint, do a power move, or lift heavy weights.
So it seems that the way to prevent muscle loss and to not lose strength is to strength train our fast-twitch muscle fibers: lift heavy weights and do power moves such as snatches, kettlebell swings, and tire flips.
So do people lose strength because their muscles decrease with age?
Although common sense tells us that strength and muscle size are correlated, what exactly is this relationship? It may not be what you think!
According to a 2011 study conducted by Andrew R. Marks, M.D., chairman and professor of physiology and cellular biophysics, the Clyde and Helen Wu Professor of Medicine, and director of the Wu Center for Molecular Cardiology at Columbia University Medical Center (CUMC,) it is suggested that sarcopenia occurs when calcium leaks from a group of proteins in muscle cells called the ryanodine receptor channel complex. These leaks then trigger a chain of events that ultimately limits the ability of muscle fibers to contract in mice.
However, when the mice were treated with a chemical that prevented the leaking of this group of proteins in their muscle cells, (the same proteins that leak in cases of muscular dystrophy,) these 4-month-old mice–roughly the equivalent of 70-year-old humans– showed significant improvements in both muscle force and exercise capacity, compared with untreated controls. The mice ran farther and faster during voluntary exercise. When their muscles were tested, they were about 50 percent stronger. (Science Daily, August 3, 2011)
Do we lose strength because we lose muscle?
An increase in muscle mass is not necessarily accompanied by an increase in muscle function because the mice treated with the chemical that prevented calcium leakage enhanced muscle strength without increasing muscle size. Maybe this is why doctors tell us to take calcium supplements as we age! So even though there is a strong relationship between muscle mass and strength, the former does not necessarily cause the decline of the latter.
So where does that leave us and the inevitable changes that will occur as we age?
The bottom line is that living a healthy lifestyle should include clean eating with a good amount of lean proteins, complex carbohydrates and exercise, including both cardio and strength training. This is the blueprint for anyone wanting to live a healthy life. The research is pretty clear: a sedentary lifestyle with a fat-laden diet is certainly not the way to go. Mindful living includes taking care of yourself, preserving muscle mass (even if it’s simply to carry out daily tasks like lifting your groceries or picking up your grandkids,) to eat “right,” and to get enough sleep.
And transforming into the wilted, elderly gym person is certainly preventable!