Some gout sufferers have experienced this: after exercise, it’s easy to fall asleep on the sofa, but then the gout came. Originally you wanted to improve gout by exercising and taking a break in time, but it didn’t work out. Gout got worse instead. What happened? In fact, this is the effect of urate crystal.
Urate may cause gout only after crystalline deposition. The higher uric acid concentration in the blood, if no crystalline deposition is present in the joints, the gout will not be induced. Therefore, to study and recognize gout, we must understand the crystal deposition of urate. In addition to the central nervous system, uric acid salts can crystallize and deposit in all parts of the body. The deposition and crystallization of uric acid salts in joints and surrounding tissues are the initiating factors of gout attack. The formation of uric acid crystals is affected by uric acid level, temperature, pH, proteoglycan, and the balance of various inhibitors and promoters affecting crystal nucleation and growth.
The solubility of urate is also related to temperature. At 37 ℃, the solubility of urate is 408 mol/l, at 30 ℃, the solubility of urate is 268 mol/l, at 25 ℃, the solubility of urate is reduced by about half, only 200 mol/l. It can be seen that the lower the temperature, the poorer the solubility of urate. When exercising, the body’s blood circulation speeds up, so the body temperature rises; when sleeping, the body temperature will gradually drop. From a relatively high body temperature to a gradual drop in body temperature, the solubility of uric acid salt becomes worse, coupled with the movement of lactic acid accumulation caused by changes in acidity and basicity, it is easier to form uric acid crystals.
Some scholars have specially studied the relationship between uric acid crystallization and body fluid pH and temperature. The results show that under the same temperature, the amount of uric acid crystallization increases with the decrease of pH (meta-acid), the amount of uric acid crystallization increases with the decrease of temperature under the same pH, and the amount of uric acid crystallization increases with the decrease of temperature when temperature and pH are the same. The number of uric acid crystals increased significantly at the same time. This suggests that lower temperatures and lower pH are beneficial to the formation of uric acid crystals. When the two factors work together, the concentration of uric acid in the blood decreases significantly, because most of the uric acid will precipitate in the joints as crystals (which may also explain why the concentration of uric acid in the blood decreases during gout attacks).
In addition, uric acid crystals generally appear around the solid particles from the liquid phase to the initial stage of nucleation. If this particle exists in the plane that makes uric acid molecules easy to aggregate, the crystallization process proceeds faster. Cartilage fragments or synovial debris produced by joint injuries may provide and become such seeds. Exercise is an important cause of joint injury, especially the first metatarsophalangeal joint, which often has the tendency of chronic damage. It is the largest force on the unit area of the joint in the whole body during walking. This is one of the reasons why the first metatarsophalangeal joint is the most frequently involved joint in the first onset and course of gout.
Summary: After exercise sleep, it is easy to appear lactic acid accumulation, body temperature drop, joint peripheral blood circulation slowdown, joint injury, etc., resulting in accelerated crystallization of urate deposition. Acute gout attacks are often caused by newly formed urate crystals in the joints, or by exfoliated microurate crystals, not by the old crystalline sediments that have long been formed and are structurally stable. Therefore, during exercise, we should control the amount of exercise and the time of exercise. At the same time, after exercise, more attention should be paid to the warmth of joints.