Marked Increase in Urinary Bicarbonate and pH Caused by Heavy Muscular Exercise wih Dynamic Knee Extension.

Abstract

In order to estimate the physiological responses to heavy muscular exercise with dynamic knee extension, the levels of urinary variables such as bicarbonate, urinary pH and blood lactate were studied before and after the exercise. Nine male volleyball players aged 19 or 20 years were involved in the present study. They performed 10%, 30% and 80% 1 repetition maximum (RM) knee extension. The levels of urinary bicarbonate and urinary pH did not change for 2.5 hours after cessation of the exercise with 10% 1 RM load, compared with the baseline levels. When 30% 1 RM loading was given, urinary bicarbonate and pH moderately increased for 2.5 hours. When 80% 1 RM loading was given, both urinary bicarbonate and pH increased immediately after cessation of the exercise, for 2.5 hours. Levels of blood lactate increased extensively within 1 minute after cessation of the exercise in the subjects with 80% 1 RM load, but no significant increase was seen in subjects with 10% 1 RM load. The changes in urinary bicarbonate and pH could be explained by the continuous production of CO2 in the muscular tissues involved in the exercise with a submaximal load where excess postexercise oxygen consumption is accelerated. It is also possible that the liver and muscle where blood lactate is aerobically metabolized could be the cause of these changes. It was also suggested that the measurement of urinary bicarbonate and pH may be useful for the estimation of events in the body after submaximal exercise loading.

Effect of exercise on fluoride metabolism in adult humans: a pilot study

“…The renal clearance of F is directly associated with the pH in the renal tubules; a more alkaline urine is likely to increase F excretion. Therefore, the reported increase in urinary bicarbonate and pH with increasing exercise intensity 34 implies a higher urinary F excretion. On the other hand, exercise increases sympathetic nervous system activity which might result in a 50% reduction in gastrointestinal secretion and blood flow 35 .…”

Significance of Post-Exercise Increment of Urinary Bicarbonate and pH in Subjects Loaded with Submaximal Cycling Exercise

“…We previously showed that urinary bicarbonate and pH markedly increased immediately after locally loaded heavy muscular exercise with dynamic knee extension (Moriguchi et al 2002a), and suggested that CO2 produced by the muscles involved in extreme submaximal loading exercise was converted to HCO3 − in the blood. As a result, the excessive amount of HCO3 − was discharged into urine because of rapid sedation of ventilation.…”

The Impact of Diet and Exercise on Drug Responses

“…Exercise affects renal excretion, for instance, by a shift to a higher urinary pH. As mentioned before, this leads to neutralization of weakly basic drugs, limiting their excretion, while acidic drugs are ionized and are thus, more easily excreted [ 170 ]. Biliary excretion also changes with exercise.…”