If your hands and feet are always freezing even in a warm room, and you are exhausted on top of it, that is not poor circulation by accident. It is your body rationing energy and sacrificing the periphery to protect the core. Here is the real mechanism, and the readout you can track yourself.
If you have Long Covid and you are cold all the time, with a thermometer reading in the 96 to 97.8 range, that is not a quirk. A subnormal body temperature is one of the disease's two defining fingerprints, and it points straight at the real problem.
If your body temperature keeps landing in the 97s and you are cold and exhausted while your thyroid labs come back normal, that gap is not nothing. Here is what a chronically low temperature actually measures, how to track it properly, and the functional fix.
Your TSH is fine. Your T4 is fine. You are freezing cold, exhausted, foggy, and your doctor says your thyroid is "perfect." You are not imagining this. The deficiency is real, it is just happening inside your cells where the blood test cannot reach.
If your basal body temperature runs below 98°F and you have classic hypothyroid symptoms but normal thyroid labs, you may be in the cohort that Wilson's Temperature Syndrome describes. This article covers the framework, the slow-release T3 protocol, and why it works when standard treatment fails.