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STILL IN MOTION
Because slowing down isn’t in the plan.
THIS WEEK'S STORY
I had a routine blood panel done a few years ago that included a 25-hydroxyvitamin D measurement — the standard marker for vitamin D status. I expected to be fine. I exercised outdoors regularly. I ate reasonably well. I was not someone who spent all day indoors.
My level was 22 ng/mL. Insufficient by any clinical standard. Not severely deficient, but substantially below the threshold associated with optimal muscle function, bone metabolism, and immune competence.
I was surprised. Most people are. Vitamin D deficiency is so prevalent in the adult population that researchers have called it a pandemic of its own. Estimates suggest 40 to 70 percent of adults over 60 in the United States have insufficient vitamin D levels, depending on geography, skin pigmentation, time outdoors, and dietary patterns.
The consequences of this insufficiency are not subtle when you understand what vitamin D actually does in the body. It is not primarily a bone nutrient. It is a hormone precursor with receptors in virtually every tissue in the body — including muscle, brain, immune cells, and the cardiovascular system.
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THE MAIN MESSAGE
Vitamin D insufficiency (defined as serum 25-OH-D below 30 ng/mL) and deficiency (below 20 ng/mL) are associated with specific measurable consequences relevant to active adults over 60:
Muscle weakness and reduced muscle function: vitamin D receptors in muscle tissue regulate protein synthesis and muscle fiber composition. Deficiency is associated with reduced type II muscle fiber function — the fast-twitch fibers most important for power, balance reactions, and strength. This is a direct sarcopenia accelerant.
Bone mineral density reduction: vitamin D is required for calcium absorption in the intestine. Without adequate D, calcium cannot be incorporated into bone regardless of dietary or supplemental calcium intake. This directly undermines the bone density work from Issue #30.
Immune function: vitamin D modulates the innate and adaptive immune response. Deficiency is associated with increased susceptibility to respiratory infections and impaired recovery from illness — both of which disrupt training consistency.
Mood and cognitive function: vitamin D receptors in the brain modulate serotonin synthesis. Multiple studies associate vitamin D deficiency with depression, cognitive decline, and reduced motivation. Restoring levels to sufficiency has documented effects on mood in deficient adults.
Testosterone synthesis: vitamin D is a co-factor in testicular testosterone synthesis in men. Studies in deficient men show significant testosterone increases with vitamin D restoration to sufficiency.
Target serum level: 40 to 60 ng/mL is the range most consistently associated with optimal outcomes in the research. Standard supplemental dose to achieve this in most adults: 2,000 to 5,000 IU of D3 daily, taken with a fat-containing meal. Have levels tested before and after supplementation — the blood test is the only way to know where you actually are.
Stretch of the Week: Standing Thoracic Side Bend with Lateral Reach
Why: A standing variation of the thoracic lateral mobility work that adds full-body integration — the reaching arm creates a longitudinal pull through the entire lateral chain from the hand through the lat, oblique, QL, and hip. Distinct from the seated version in Issue #41.
How to do it:
Stand with feet hip-width apart, right arm extended overhead
Keeping both feet planted, reach the right arm up and over to the left as far as comfortable
Let the left hand slide down the left thigh for balance and as a guide for the lateral lean
Hold 3 seconds at end range, feeling the stretch from the right hand to the right hip
Return to upright, switch sides
8 to 10 reps each side, 2 rounds
Tuesday expands with three vitamin D-related mobility connections and the sun exposure protocol that supports vitamin D synthesis without excessive UV risk.
Strength Move of the Week: Dumbbell Lateral Raise
Purpose: Strengthens the middle deltoid through shoulder abduction — a movement pattern not specifically targeted by any previous SIM60 strength exercise. Important for overhead reach capacity, shoulder width stability, and the rotator cuff support that lateral deltoid strength provides.
How to do it:
Stand or sit, a light dumbbell in each hand at the sides, elbows very slightly bent
Raise both arms out to the sides until the hands reach shoulder height — not higher
Lead with the elbows, not the hands — the elbow should be slightly higher than the wrist at the top
Hold 1 second at shoulder height, lower slowly over 3 seconds
12 to 15 reps, 3 sets — use a weight lighter than you think is necessary
The common error: raising the arms above shoulder height, which compresses the subacromial space and loads the impingement zone. Shoulder height is the end range for this exercise, and stopping there is both safer and more effective for middle deltoid targeting.
Thursday covers three shoulder abduction progressions and the specific connection between vitamin D status and shoulder muscle function.
Suggested Equipment: Vitamin D3/K2 Supplement + 25-OH-D Blood Test
Vitamin D3 (cholecalciferol) is the form that most effectively raises serum levels. K2 (as MK-7) directs the calcium that vitamin D makes available into bone rather than arterial walls. The combination is covered in Issue #30 from the bone density perspective — here the rationale extends to muscle function and immune health. The 25-hydroxyvitamin D blood test is the standard measurement, available through any physician order or, in many states, through direct-to-consumer testing services without a doctor’s visit.
Saturday covers the complete vitamin D optimization toolkit and the testing approach.
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THE TAKEAWAY
Vitamin D is not a bone supplement. It is a hormone precursor that regulates muscle function, immune response, mood, and bone metabolism simultaneously. Deficiency in any of these systems is measurable and correctable. A blood test and a few dollars of D3 per month is the most cost-effective health investment most adults over 60 have not yet made.
YOUR TURN
Have you had your vitamin D level tested? If yes, where was it, and did you supplement? If no, is it something you’ve considered? Reply and tell me. I’m curious how widespread this deficiency is in this specific community.
Still moving forward,
— The SIM60 Team
simsixty.com · Because slowing down isn't in the plan.
Educational content only. Not medical advice. SIM60 is not a medical provider and does not diagnose or treat any condition. Consult your physician or a licensed physical therapist regarding your specific symptoms before beginning any exercise described here.
