Inflammation
The immune response to injury or stress: protective when acute, damaging when chronic.
Inflammation is the immune system's response to injury, infection or stress: blood flow rises, immune cells arrive, and signalling molecules coordinate the clean up and repair. Acute inflammation is not damage, it is the mechanism of healing, and without it wounds would not close.
The problem is the chronic version. Low grade inflammation that persists for years, without an infection to fight, is associated with cardiovascular disease, insulin resistance, some cancers and the general decline that ageing research now often frames in inflammatory terms.
Training is an interesting case because it is both. A hard session produces a transient inflammatory response, and regular training over months lowers baseline inflammatory markers. The acute spike is part of how the adaptation happens, which is why blunting it aggressively can be counterproductive.
That is the practical catch with recovery tools. Anti-inflammatory drugs taken routinely around training, and cold water immersion soon after resistance work, can reduce soreness while also reducing the adaptive signal. Use them when you need the recovery more than the adaptation, not by default.
The measurable version in a blood test is usually hs-CRP, a general marker that rises with infection, injury, obesity and smoking alike. It is informative in context and meaningless on its own, since a cold last week will move it.
What lowers chronic inflammation is unglamorous: regular exercise, losing excess visceral fat, sleeping enough, not smoking, and a diet with enough fibre and unsaturated fat. Anti-inflammatory supplement lists mostly sell mechanisms rather than outcomes.
In practice, treat a raised marker as a prompt to look at those inputs and, if it stays raised without explanation, to see a doctor rather than to buy turmeric.