Table 2.

Sweat sodium concentrations and losses with physical activity^a

First author (reference)	N	Sex	Mean age (y)	Country	Temp (°C)	Relative humidity (%)	Physical activity			Sweat Na concentration		Mean sweat Na loss [g (mmol)]
							Levela	Type	Duration (min)	Mean [g/L (mmol/L)]	Range [g/L (mmol/L)]
Gibson (50)	34	F	16	Canada	10	63	Elite	Soccer	90	1.1 (48)	0.6–1.6 (27–68)	0.7 (30)
Kurdak (82)	22	M	20	Turkey	34	64	ND	Soccer	90	0.9–1.1 (43–46)	0.6–1.4 (25–59)	3.2 (137–140)
Horswill (62)	14	M	24	United States	29–32 (WGBT)	ND	ND	Football	132	0.9–1.2 (38–53)	ND	ND
Kilding (78)	13	F	23	New Zealand	6–14	71–74	International	Soccer	90	1.0–1.1 (44–46)	ND	0.7–0.8 (32–35)
Maughan (101)	9	M	19	Canada	36 (27 water)	ND	Trained elite	Swimming	105	1.0 (44)	ND	ND
Maughan (101)	8	F	21	Canada	36 (27 water)	ND	Trained elite	Swimming	105	0.9 (39)	ND	ND
Palmer (117)	44	M	18	Canada	14	66	Elite	Ice hockey	60	1.2 (54)	0.6–2.0 (27–88)	2.3 (98)
Shirreffs (131)	92	M	18	Tunisia	25–28	ND	After 3-w trainingb	Soccer	60–70	0.4–0.5 (17–20)	0.1–1.2 (6–50)	0.7 (28–29)
Hashimoto (54)	7	M	47	Japan	ND	ND	ND	Badminton	180	2.1 (91)	1.2–2.9 (52–126)	2.8 (122)
Hashimoto (54)	5	F	50	Japan	ND	ND	ND	Badminton	180	0.9 (41)	0.4–1.6 (18–68)	ND
Maughan (102)	20	M	21	England	6–8	50–60	Premier league	Soccer	95	1.4 (62)	0.6–2.1 (25–90)	2.4 (104)
Shirreffs (130)	26	M	26	Seven countriesc	32 (22 WGBT)	20	International professional	Soccer	90	0.7 (30)	0.4–1.5 (16–66)	1.5 (67)

^aAbbreviations: F, female; M, male; N, number of participants; ND, no data or not determined; WBGT, wet bulb globe temperature, an index used for the assessment of heat stress.

^bLevel of athletes as reported by the investigators. In Shirreffs & Maughan (131), the level is not reported, but measures of sweat were started after three weeks of training among athletes living together in a residential facility.

^cAthletes from seven countries; countries are not listed (130).