Sweat Facilitated Amino Acid Losses in Male Athletes during Exercise at 32-34°C

Abstract

Sweat contains amino acids and electrolytes derived from plasma and athletes can lose 1-2L of sweat per hour during exercise. Sweat may also contain contributions of amino acids as well as urea, sodium and potassium from the natural moisturizing factors (NMF) produced in the stratum corneum. In preliminary experiments, one participant was tested on three separate occasions to compare sweat composition with surface water washings from the same area of skin to assess contributions from NMF. Two participants performed a 40 minute self-paced cycle session with sweat collected from cleansed skin at regular intervals to assess the contributions to the sweat load from NMF over the period of exercise. The main study investigated sweat amino acid composition collected from nineteen male athletes following standardised endurance exercise regimes at 32–34°C and 20–30% RH. Plasma was also collected from ten of the athletes to compare sweat and plasma composition of amino acids. The amino acid profiles of the skin washings were similar to the sweat, suggesting that the NMF could contribute certain amino acids into sweat. Since the sweat collected from athletes contained some amino acid contributions from the skin, this fluid was subsequently referred to as “faux” sweat. Samples taken over 40 minutes of exercise showed that these contributions diminished over time and were minimal at 35 minutes. In the main study, the faux sweat samples collected from the athletes with minimal NMF contributions, were characterised by relatively high levels of serine, histidine, ornithine, glycine and alanine compared with the corresponding levels measured in the plasma. Aspartic acid was detected in faux sweat but not in the plasma. Glutamine and proline were lower in the faux sweat than plasma in all the athletes. Three phenotypic groups of athletes were defined based on faux sweat volumes and composition profiles of amino acids with varying relative abundances of histidine, serine, glycine and ornithine. It was concluded that for some individuals, faux sweat resulting from exercise at 32–34°C and 20–30% RH posed a potentially significant source of amino acid loss.

Physiology of sweat gland function: The roles of sweating and sweat composition in human health

“…pyrrolidone carboxylic acid, urocanic acid, serine, histadine, ornithine, glycine, alanine, aspartic acid, lysine) a NA NA Secretory mechanisms are unknown [6]. Present in sweat but varied in concentrations perhaps because of contamination [15] Natural skin moisturizers, maintain barrier integrity of skin [206,207] Skin surface contamination, both of epidermal origin and residual amino acids in the sweat gland lumen [15,136,207] Proteolytic enzymes a NA NA Derived from eccrine sweat gland [10,456] and/ or epidermis [423]. Concentrations increase with increasing sweating rate [457].…”

The atmospheric chemistry of indoor environments

“…[42][43][44][45][46] -Humans: ammonia, amino acids, small VOCs such as isoprene and lactic acid, unsaturated oils such as squalene, triglycerides, and fatty acids, personal care products such as siloxanes. [29][30][31][47][48][49][50][51] -Microbes: VOCs. 52 -Consumer products: phthalates and many others, including volatile chemical products (VCPs).…”

Diverse characteristics of the urinary excretion of amino acids in humans and the use of amino acid supplementation to reduce fatigue and sub-health in adults

“…High levels of exercise activity would increase the requirement for protein intake and for protein turnover in order to offset the increased losses of free amino acids arising from demands for energy metabolism, tissue repair and recovery processes [8, 9] as well as excretory losses via sweating [10, 11]. Similar increased demands for amino acids would be seen during illness and recovery from trauma.…”

“…It has been shown that the levels of several key amino acids including serine, glycine, histidine, alanine and ornithine are present in sweat at much higher concentrations than occur in the plasma [10, 11, 14, 15]. It was proposed that these levels of amino acids in sweat, as has been found to be the case with sweat electrolytes [16], could be achieved by a process of leaching of the amino acids from the natural moisturising factor in the stratum corneum of the skin to combine with the quantities excreted in sweat [10, 11, 15].…”

“…It was proposed that these levels of amino acids in sweat, as has been found to be the case with sweat electrolytes [16], could be achieved by a process of leaching of the amino acids from the natural moisturising factor in the stratum corneum of the skin to combine with the quantities excreted in sweat [10, 11, 15]. The majority of amino acids which constitute the natural moisturising factor are thought to be derived from the protein filaggrin which is primarily composed of glutamine/glutamic acid, arginine/ornithine, serine, proline, glycine, histidine, and aspartic acid/alanine [17].…”