A preview of this full-text is provided by Wiley-VCH.
Content available from ChemElectroChem
This content is subject to copyright. Terms and conditions apply.
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
Relationship Between Sweat and Blood Lactate Levels
During Exhaustive Physical Exercise
Elena V. Karpova,[a] Aleksey I. Laptev,[b] Egor A. Andreev,[a] Elena E. Karyakina,[a] and
Arkady A. Karyakin*[a]
In contrast to the generally accepted view, that sweat lactate is
irrelevant to blood, we report on the suitability of sweat lactate
for diagnostics. We demonstrate a significant increase in lactate
concentration in sweat from the working muscle area simulta-
neously with the rise of blood lactate content during exhaustive
physical exercise. The variation rates of lactate concentration in
sweat from working and latent muscle areas correlate positively
with blood lactate levels (r>0.8 and r=0.7, respectively), thus
offering the prospect of a non-invasive approach for the
monitoring of sportsperson training. Moreover, sweat lactate,
being the faster indicator of muscle metabolism, would be even
more important for sports medicine than the nowadays-used
blood lactate.
l-Lactate, being the end product of anaerobic glucose metabo-
lism (glycolysis), has become one of the most important
metabolites in clinical analysis. Besides lactic acidosis,[1] its
increase in blood is induced by physical exercises[2] up to 10–15
times,[3] allowing to control training level of sportsmen, for
example, calculating lactate anaerobic thresholds.[3b,4] However,
lactate monitoring is not involved in everyday sports training
because collection of blood samples is not convenient and safe.
Non-invasive monitoring of sports training through analysis
of sweat is extremely attractive because the latter is excreted
spontaneously during physical exercises. However, after the first
paper reporting a significant increase of sweat lactate level
upon exhaustive physical exercise,[5] the reports on no signifi-
cant relationship appeared.[6] Considering these unsuccessful
correlations and the report that sweat lactate was derived
metabolically from blood glucose rather than from blood
lactate,[7] the negative conclusion on the possibility for non-
invasive diagnostics on the basis of sweat lactate was made.[8]
This raises a doubt concerning usefulness of the recently
reported sweat lactate sensors and monitors.[9]
We note that, firstly, the relationship between sweat and
blood lactate levels can be dependent on the skin area from
which the sweat samples have been collected (either working
or latent muscle area). The supposition is based on the fact that
lactate content in sweat samples taken from different skin areas
varies significantly.[10] .Secondly, the sufficient requirement for
diagnostics would be a positive correlation between blood and
an excretory liquid (sweat) in variation rate of metabolite
content rather than of its absolute concentration.[11] Indeed,
considering lactate production rate, the significantly improved
correlation between muscle lactate and blood lactate was
reported.[12] We report here on positive correlation in variation
rates of lactate concentration in blood and in sweat as from
working, as from latent muscle areas.
Since for diagnostics the correlation in variation rate rather
than in absolute metabolite concentration is required (above),
the exhaustive incremental cycle ergometer exercise has been
chosen in order to cause the raise in blood lactate. The
sweating stimulation through electrophoresis of pilocarpine has
been chosen because, first, it does not change the sweat lactate
content during the exercise[8] and, second, after such activation
lactate concentration in sweat is independent of the rate of
sweating.[13] Moreover, using continuous diabetes monitor
reported in,[11] we have shown that after pilocarpine activation
the rate of sweating retains at a constant level within 30
minutes (Figure S1, Supporting Information), which is enough
for the exhaustive incremental exercise.
Ten healthy human volunteers were subjected to the
exercise, simultaneously blood samples were taken from their
fingers and sweat samples were collected from both working
and latent muscle areas. For this aim sweat collectors were
placed on their leg (thigh) and arm, respectively.
Sweat analysis is hardly possible with commercial clinical
analyzers, because their biosensors are based on platinum as
electrocatalyst for hydrogen peroxide oxidation. On the con-
trary, as we have shown already in,[14] Prussian Blue based
hydrogen peroxide sensor is practically independent of the
presence of platinum harming sweat components. Accordingly,
sweat samples diluted 1000 times have been analyzed using
flow-injection analyzer (FIA) equipped with Prussian Blue (nano-
zymes “artificial peroxidase”[15]) based lactate biosensor. The
dynamic range of the FIA system prolongs from 1 μM to 1 mM
of lactate concentrations (Figure S2, Supporting Information).
Sweat analysis does not affect the biosensor response; the
typical responses to 1000 times diluted sweat samples after
calibration with lactate containing model solution are displayed
in the Figure S3, Supporting Information). Since sweat samples
[a] E. V. Karpova, Dr. E. A. Andreev, Dr. E. E. Karyakina, Prof. A. A. Karyakin
Chemistry faculty
M.V. Lomonosov Moscow State University
Leninskie gory, 1, build. 3, 119991 Moscow, Russia
E-mail: aak@analyt.chem.msu.ru
[b] Dr. A. I. Laptev
Institute of Sports and Sports Medicine
Russian State University of Physical Education, Sports, Youth and Tourism
Moscow, Russia
Supporting information for this article is available on the WWW under
https://doi.org/10.1002/celc.201901703
Communications
DOI: 10.1002/celc.201901703
191ChemElectroChem 2020,7, 191– 194 © 2020 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Wiley VCH Donnerstag, 02.01.2020
2001 / 155492 [S. 191/194] 1
