MUSCLE is a matter of HEALTH

Health, July 15, 2021

Muscle is not just for moving you - it is far more important for wellbeing and longevity than you realise.

Muscle (when combined) is the largest endocrine organ in the body, this means they produce hormones. The loss of muscle mass is linked to many major disease states as well as loss of function. It is the key to functional, healthy longevity! We need to switch the initial conversation about being overfat (the external issue) to being undermuscled. This can be less confronting for people. It's time the medical world focused on the solution rather than the problem - we need to be more muscle centric in our education. Muscle is not just for moving us around it's our metabolic currency. It's the largest site for glucose disposal (up to 80% of glucose disposal - almost everything you eat), muscle is also a large site for fatty acid oxidation, and the reservoir for our amino acids. Muscle is excellent at utilising and creating energy - it's the mitochondria in the muscle cells that are the literal power plants. When muscle is replaced with adipose (fat) tissue you have less ability to produce energy with less mitochondria. Muscle cells contain more and better quality mitochondria than fat cells as they have to release large amounts of energy quickly. Generally there is a positive correlation between cell activity and the number of mitochondria. 


There are several studies of that show that the usual massive decline in mitochondria (usual is 50-70% loss of mitochondrial capacity from ages 20 to 70) DOES NOT happen in people who are life long exercises. It's a combination of resistance work (keeping the muscle fibre robust and healthy) plus the aerobic work to enhance the oxidative capacity. It is NOT just one or the other. As a society we need to prolong health span and function with more muscle and not rely solely on pharmaceutical agents and excessive 'rest' home care for just life span. Maybe we need to re-brand rest homes as activity villages! Quality and optimising life should always be our health goal just just prolonging it.  We can't keep losing functionality later in life as a result of physical weakness and lack of cardiovascular fitness.

The more muscle (to a point - too much still creates excessive weight for joints), the less overall mortality. When you contract muscle you secrete myokins which help combat many disease states. They protect our bones, brains, heart and liver. There are many myokins. There is BDNF which goes to the brain. Interleukins, including interleukin-6 (also secreted by macrophages) which is part of the immune system and up-regulated to boost immunity in response to infection. 

You could be the same weight at 65 as 25 but have more fat and less muscle. As we age we acquire anabolic resistance - that is our skeletal muscle is not able to respond as well to anabolic stimuli by stimulating protein sysnthesis.  Our biology and hormone cycles are regulated by muscle - if you lose muscle your cortisol and insulin rises and your growth hormone, and testosterone decreases. This is matched with a natural loss of testosterone and growth hormone after we hit 40 years old. We simply can't process the protein we consume as effectively compared to when we were younger. We need to eat more protein as we age. It is the essential building block of everything and all our 20,000 genes produce protein. The lower your kcal intake the higher the protein content should be. Sarcopenia is the term used for muscle loss, and this is getting more prevalent at younger ages in the western world as we become more sedentary, and seeking comfort is associated with wealth and success.   Data drives results - you can't manage what you can't measure. Having a dexa scan or a caliper test is a good way of checking your skeletal muscle percentage and keeping track over time. 


How to optimise muscle? 

1)Proper nutrition - as you age and your growth hormone, and testosterone decrease you have to be more mindful with what your consume. All evidence based diets have overlapping advice - low in saturated fat, low in trans fat, low in ultra processed food and good amounts of fibre. Naturally this leads to plant predominant eating. Have a whole food plant slant. Increasing your protein intake and distributing your protein intake over the day is important as we age. Leucine (branched chain amino acid, BCAA) has shown to be a very important essential amino acid, plant food sources of leucine include soy, pumpkin seeds, lentils, and tempeh.  I look for 1.8g (55mg of leucine) of protein per kg of bodyweight when I'm training 7-10 hrs/wk. I am around 70kg so I will try to get in around 110-120g per day and spread it over 3 meals and a afternoon snack. 

2)Resistance Training - At least 1-2 x a week for 10-20min building up to using weights as we have to change the tissue (compound lifts eg deadlift, squat, and kettlebell swings) and microchunks of body weight activity daily. You manage to brush your teeth twice a day for 90sec so 30-60sec of squats, push ups, lunges, and planks should become part of your full body strength routine. I talk about the three pillars of physical fitness being - i) Cardiovascular fitness, ii) Flexibility/mobility/balance iii) Strength/core/full-body strong

Body composition may be a good predictor of mortality risk. Overall we need more muscle and less fat to create and promote optimal functional wellbeing. So let's reflect this knowledge with daily actions that look after our muscle.