Effect of a low-carbohydrate diet on plasma and sweat ammonia concentrations during prolonged nonexhausting exercise

Abstract

The purpose of this investigation was to examine the effect of low body glycogen stores on plasma ammonia concentration and sweat ammonia excretion during prolonged, nonexhausting exercise of moderate intensity. On two occasions seven healthy untrained men pedalled on a cycle ergometer for 60 min at 50% of their predetermined maximal O2 uptakes (VO2max) firstly, following 3 days on a normal mixed diet (N-diet) (60% carbohydrates, 25% fat and 15% protein) and secondly, following 3 days on a low-carbohydrate diet (LC-diet) (less than 5% carbohydrates, 50% fat and 45% protein) of equal energy content. Blood was collected from the antecubital vein immediately before, at 30th and at 60th min of exercise. Sweat was collected from the hypogastric region using gauze pads. It was shown that plasma ammonia concentrations after the LC-diet were higher than after the N-diet at both the 30th and 60th min of exercise. Sweat ammonia concentration and total ammonia loss through the sweat were also higher after the LC-diet. The higher ammonia concentrations in plasma and sweat after the LC-diet would seem to indicate an increased ammonia production, which may be related to reduced initial carbohydrate stores.

A Review of the Literature on the Application of Blood Ammonia Measurement in Sports Science

“…Czarnowski, Langfort, Pilis, & Gorski (1995) used an incremental exercise test (5 min of exercise interspaced with 5 min of rest) on a cycle ergometer to study the effect of diet on exercise ammonia at various exercise in-…”

Sweat Lactate, Ammonia, and Urea in Rugby Players

“…trogen loss is important during exercise, playing a role in preventing excessive elevation of ammonia in body fluids [8,10,23]. Urea is produced in liver tissue from ammonia and carbon dioxide and sweat has also been shown to contain considerable amounts of urea coming from the plasma [9].…”

Influence of ambient temperature on plasma ammonia and lactate accumulation during prolonged submaximal and self-paced running

“…However, Czarnowski et al (1995) have shown that rapid rates of [NH 4 ] accumulation are unlikely to be due to low glycogen stores. In exercising muscles of patients with glycogen storage disease there was an enhanced purine metabolism in the absence of any change in [La ± ] accumulation (Mineo et al 1985).…”