Table 3. Comparison of amino acid concentrations in sweat from the “Low”, “Intermediate” and “High” SFLAA clusters compared with the post-exercise composition of plasma.

	Post-exercise plasma amino acid concentrations (P) (μM ± SE)	Sweat amino acid concentrations per SFLAA cluster (μM ± SE)			Sweat—Plasma concentrations (μM)
Amino acid	Primary group (n = 10)	Low (L) Total amino acids <4 000 (n = 8)	Intermediate (I) Total amino acids 4,000 to 10,000 (n = 7)	High (H) Total amino acids >10,000 (n = 4)	L-P	I-P	H-P
Serine	49 ± 4	582a ± 135	1,160b ± 111	2,410d ± 359	533	1,111	2,361
Glycine	193 ± 84	349a ± 36	682b ± 78	1,590c,d ± 146	156	489	1,397
Alanine	499 ± 23	235a ± 28	457 b ± 40	1,170c,d ± 73	-264	-42	671
Histidinee	48 ± 2	212a ± 54	1,010 b ± 379	3,300d ± 986	164	962	3,252
Ornithine	34 ± 2	151a ± 33	1,340 b ± 352	2,150d ± 530	117	1,306	2,116
Aspartate	0	119a ±18	251 ± 33	322 ±130	119	251	322
Lysinee	142 ± 6	104 ± 31	414 b ± 152	1,340d ± 352	-38	272	1,198
				Sub-totals	787	4,349	11,317
Threoninee	89 ± 5	117 ± 27	212 ± 33	250 ± 108	28	123	161
Valinee	258 ± 12	99a ± 8	190 b ±27	445c,d ±24	-159	-68	187
Leucinee	120 ± 4	87 ± 20	212 b ± 51	477d ± 74	-33	92	357
Glutamic acid	39 ± 3	68 ± 23	196 b ± 24	378c,d ± 67	29	157	339
Proline	207 ± 9	59a ± 8	93 ± 9	156d ± 38	-148	-114	-51
Glutamine	380 ± 19	58a ± 16	42 ± 16	163 ± 71	-322	-338	-217
Phenylalaninee	49 ± 2	48 ± 10	122 b ± 29	277d ± 41	-1	73	228
Isoleucinee	61 ± 2	47 ± 8	114 b ± 21	288d ± 35	-14	53	227
Tyrosinee2	1 ± 1	34a ± 13	72 ± 36	103 ± 59	33	71	102
Asparagine	32 ± 2	20 ± 6	60 b ± 9	114c,d ± 19	-12	28	82
Tryptophane	31 ± 2	11a ± 6	52 b ± 17	215d ± 57	-20	21	184
α-aminoadipic acid	3 ± 1	9 ± 5	27 ± 10	153d ± 36	6	24	150
Hydroxylysine	0	2 ± 1	23 b ± 10	171d ± 36	2	23	171
Hydroxyproline	2 ± 1	0	14 ± 6	3 ± 2	-2	12	1
				Sub-totals	-613	157	1,921
Total Amino Acid Concentrations in Post-exercise Plasma and Sweat (mM)	2.2 ± 0.15	2.4 ± 0.26	5.9b ± 0.63	15.2c,d ± 1.6
				Sub-totals	0.2	3.9	13.0
Resting Total Amino Acid Concentrations in Plasma (mM)		2.45 ± 0.25	2.39 ± 0.09	2.24 ± 0.11
Estimated total sweat volume per hour exercise period, L/hour, (n = 11)	Primary Group	2.3 ± 0.30 (n = 4)	1.8f ± 0.33 (n = 3)	1.5g ± 0.1 (n = 3)
Estimated total amino acids lost/hour exercise period, mmoles, (n = 11)	Primary Group	5.1	10.6	22.8

^a The concentrations of amino acids in sweat for the “Low” cluster were significantly different compared with corresponding levels in the plasma (P < 0.05). The sweat parameters were assessed by Tukey’s HSD for unequal N where

^b Intermediate > Low

^c High >Intermediate

^d High > Low (P<0.05)

^f Intermediate<Low

^g High<Low.

^e Essential amino acids

^e2Tyrosine can be synthesised from phenylalanine and cysteine (within cystine) can be synthesised from methionine and serine.