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Exercise
Int J Sport Nutr Exerc Metab 2001 Jun;11(2):248-57
The effect of low-carbohydrate diet on the
pattern of hormonal changes during incremental, graded exercise in
young men.
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Langfort
JL, Zarzeczny R, Nazar K, Kaciuba-Uscilko H.
Department of Applied Physiology, Medical Research Centre, Polish Academy of
Sceinces, 5 Pawinskiego Str., PL-02-106 Warsaw, Poland. |
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purpose of this study was to discover whether severe dietary carbohydrate
(CHO) restriction modifies the relationship between exercise intensity
and hormonal responses to exercise. Changes in the plasma adrenaline
(A), noradrenaline (NA), growth hormone (hGH), testosterone (T),
and blood lactate (LA) during an incremental exercise performed
until volitional exhaustion were determined in 8 physically active
volunteers after 3 days on low CHO (< 5% of energy content;
L-CHO) and isocaloric mixed (M) diets. Following L-CHO diet, the
basal plasma A, NA, and hGH concentrations were increased, whilst
T and LA levels were decreased. During exercise all the hormones
increased exponentially, with thresholds close to that of LA. Neither
the magnitude nor the pattern of the hormonal changes were affected
by L-CHO diet except the NA threshold, which was lowered. Blood
LA response to exercise was diminished and LA threshold was shifted
towards higher loads by L-CHO diet. It is concluded that restriction
of CHO intake (a) does not affect the pattern of changes in plasma
A, hGH, and T concentrations during graded exercise but lowers
NA threshold, indicating increased sensitivity of the sympathetic
nervous system to exercise stimulus; (b) alters the basal and exercise
levels of circulating hormones, which may have an impact on the
balance between anabolic and catabolic processes and subsequently
influence the effectiveness of training. |
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| PMID:
11402256 [PubMed - indexed for MEDLINE] |
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