There are instances when a picture can really help tell a story. Case in point, with the photo shown here. This is one of the best photos for showing what muscle and fat actually look like (via a cross-sectional view from an MRI scan). Secondly, it can be used as a great motivational tool for showing the difference between an active and sedentary person’s muscles and the effect exercise can have on it. We will take a deeper dive into these three photos but let’s first set the stage.
You are probably aware that to get a muscle larger and stronger many variables need to come into play. To build muscle you must consistently overload that muscle to the point of momentary muscular failure. If this continues to happen consistently over time, with a progressive overload, the muscle fibers will increase in size, this is known as muscle hypertrophy. As muscles increase in size, you’re able to generate more force and power. As a result you typically see an increase in strength level and among other things, your bones also become stronger. You can build strength and muscle size at any age but it becomes more difficult as one gets older. Both muscle strength and size increase up to age 25-35 and typically maintained to around 50-years old dependent upon on activity level. If you do not strength train and stay active there is an increase likelihood that sarcopenia will set in. Sarcopenia is the loss of muscle mass as a result of advancing age. It is possible to lose 8-10% of your muscle mass between the ages of 40 and 50 and this number could potentially increase to 15% per decade after age 75 if an inactive lifestyle is followed.
Wroblewski and colleagues performed a study (2011) on forty Masters athletes (age 40-70+), evenly split between the sexes, all were triathletes working out 4-5 times a week. This particular set of MRI scans show three different cross-sectional shots of a quadriceps muscle (thigh) from test subjects. The top photo is of a 40-year old triathlete, the middle photo belongs to a 74-year old sedentary man while the bottom photo is that of a 70-year old triathlete. The white area constitutes adipose tissue (fat) and the darker colored area is the good stuff, metabolically active lean muscle tissue. The first thing that I want you to notice is the similarity between the top and bottom photos. There is a 30-year age difference between these individuals but the lean muscle and body fat levels look almost identical. The scans are both of Masters athletes and there is not a better photo that demonstrates the validity of the use it or lose it principle.
The final point I want to make is you have a choice in the matter of how well you age, if you take the sedentary road, you may end up looking like the middle photo of the sedentary 74-year old. Otherwise, your goal should be to continue taking that magic pill to prevent the loss of both muscle and functionality. If not, activities of daily living like getting up a flight of stairs or getting into a car will become maximal efforts and eventually, assistance will be needed. That pill by the way is exercise with an emphasis on strength training. The great thing about strength training is you don’t need to do it everyday; just 2-3 times a week will keep you looking and feeling years younger.
Credit: MRI scans of the quadriceps of a 40-year-old triathlete, a 70-year-old triathlete and a 74-year-old sedentary man is from Wroblewski et al. and their research paper can be read here. Chronic Exercise Preserves Lean Muscle Mass in Masters Athletes, Andrew Wroblewski, Francis Amati, et al. The Physician and Sports Medicine, 39(3):172-178, 2011. A second paper on Masters athletes that you may want to read, Endurance Exercise in Masters Athletes can be found here Journal Physiology 586(1):55-63, 2008.