Acute effects of moderate intensity exercise on uric acid excretion in underexcretion hyperuricemia

Uric acid excretion insufficiency is a major etiology of Hyperuricemia (HUA). While exercise intervention serves as a non-pharmacological uric acid-lowering strategy, acute exercise may cause transient serum uric acid (SUA) elevation, posing risks to HUA patients. This pilot study investigated the acute effects of a single bout of moderate-intensity continuous training (MICT) on SUA and uric acid excretion indices in young men with underexcretion hyperuricemia, aiming to characterize the acute physiological responses, with a focus on potential safety implications. This was a pilot study using a self-controlled pre-post design. Prior to the experiment, 24-hour urine collection and fasting venous blood sampling were conducted. Patients were classified based on 24-hour urinary uric acid (UUA) excretion and fractional excretion of urate (FE_UA). A total of 18 patients with Underexcretion Hyperuricemia were finally included in the acute MICT intervention. Blood/urine samples were collected pre-intervention, post-intervention, and 30 min post-intervention. No statistically significant changes were observed in SUA or UUA following the acute exercise intervention (P > 0.05). Notably, key uric acid excretion indices increased significantly at 30 min post-intervention: fractional excretion of urate (FE_UA, P < 0.001), UUA/creatinine ratio (UUA/UCr, P < 0.01), and Simkin index (P < 0.001) were all markedly higher than pre-intervention levels. Additionally, blood lactate was significantly elevated immediately post-intervention (P < 0.01), and serum creatinine (SCr) increased significantly both immediately and 30 min post-intervention (both P < 0.05). MICT did not induce a statistically significant acute increase in SUA in this pilot cohort, while uric acid excretion indices increased after exercise. Although no apparent large acute SUA surge was observed within the post-exercise window, these findings are preliminary, and confirmatory controlled trials in larger and more diverse populations are required.