It is estimated that as much as half the world, including more than 40% of Americans, have low levels of vitamin D (≤20 ng/mL). People with darker skin and people who seldom go unprotected under the sun are especially at risk.
Low levels of vitamin D have been associated with depression. The decrease in vitamin D production caused by reduced sunlight during the winter months may be a factor in seasonal affective disorder (SAD).
If your vitamin D levels are not low, supplementation isn’t likely to benefit your mood. If they are low, supplementation is more likely to help if you suffer from major depression.
If you suspect your vitamin D levels are low, you can have them assessed through a 25-hydroxyvitamin D blood test. Assessing your vitamin D levels twice in a year — in midsummer and midwinter, when there is the most and least sunlight — is an efficient way of estimating what your levels are around the year.
Here is a piece from Doug Kelsey on the strength required for running:
World class long distance runners are not built like sprinters.
But both are strong.
When they run, they seem light-footed, have a slight bounce in their step. Compare this to a runner who you can hear coming a hundred yards away because of how hard his feet hit the ground.
Runners who excel at their sport have, what I call, a strong “Suspension System”. And because of this, they minimize the risk of injury (they can’t eliminate it of course but can reduce the risk).
The Suspension System consists of muscle, connective tissue (fascia, tendons) and the joint surface (cartilage) of the ankle, knee, and hip.
When a muscle contracts, it produces a force within that muscle but the force spreads beyond the local attachments via the myofascial sling – fascial sheaths connecting muscles to each other as well as to tendons and bones.
A well developed biologic Suspension System is a tensegrity structure.
Tensegrity refers to the balanced tension among various members to create structural integrity. The tensegrity concept is used in architecture for bridges and buildings. The combined tension among cables and beams makes the structure remarkably strong yet lighter weight than steel beams.
Inadequate muscle strength creates an inadequate and imbalanced myofascial sling network and in turn, can overload the knee joint. For example, hip weakness is linked with knee pain.1)
If your knee hurts, there’s no question that strengthening the quadriceps muscle helps – if you can do it. One of the challenges with knee pain is that it often interferes with the strengthening of muscle since the force required to fatigue the muscle is often greater than what the knee joint can withstand.
But, the knee serves at the pleasure of the hip and foot (and you can argue that the trunk is in there too). You have to strengthen the entire chain for long-term success.
The next time you go for a run, check your “springiness”. If you find yourself lacking a bit of it, it likely means that some part of your Suspension System needs attention.
That’s all I have for now.
Thanks for reading.