The same chemistry that turns bread into toast is also at work inside aging muscle.
Sugar molecules in the bloodstream latch onto collagen and form what researchers call advanced glycation end-products, according to work published in the Journal of Applied Physiology. These byproducts act like tiny welds, cross-linking the collagen fibers that wrap every muscle. Welded collagen does not glide. It resists, so you feel stiff. The effect builds over decades, and it runs faster when blood sugar stays high for years, as in poorly controlled diabetes. A dessert here and there isn't the problem.
That is a big part of why stiffness in the hands, shoulders and legs is not the same problem as arthritis. The joints may be fine. It is the muscle and the connective tissue around it that have lost their give. Muscle fibers also shrink and thin with age, a process called sarcopenia, leaving less elastic tissue behind, according to research in Frontiers in Physiology.
Sitting makes it worse fast. Two hours in a chair holds the hip and leg muscles in a shortened position, slows circulation and lets tissue settle. Standing up then feels like pulling against an anchor.
Movement usually does loosen things, but not always. Ordinary stiffness eases within a few minutes of walking around. Stiffness that does not ease, or morning stiffness in the shoulders and hips that drags on past 45 minutes, is a different animal. It can point to polymyalgia rheumatica, an underactive thyroid or a reaction to statin drugs, according to the Cleveland Clinic.
Cramps follow their own rules. Roughly a third of adults over 60 get night leg cramps regularly, and dehydration, low magnesium or potassium, and common prescriptions — diuretics, blood pressure medicines, some antidepressants — are frequent culprits, the Cleveland Clinic reports. Standing on a cold floor and shifting weight onto the cramping leg stretches the muscle and usually breaks the spasm.
Rick Good spent ten years in the newspaper business, including with The News & Observer (Raleigh, NC) and The Greenville News (Greenville, SC). He co-wrote, with Melinda Coleman, Rutledge to Riley: Governors of South Carolina, 1776–Present (Published by The Greenville News), and is the author of Mind Games Trivia #1 (Amazon). He has recently spent 15 years creating original trivia content through Sounds Good Mobile Entertainment and continues that with his new company, SGME Software. He edits The Smart Reader’s money, real estate, and business coverage.