The First Lactate Threshold Is a Limit for Heavy Occupational Work.

Autor:	Fasching P; Private Clinic Maria Hilf, Radetzkystraße 35, 9020 Klagenfurt, Austria.; Center for Occupational Medicine AMEZ, Hergottwiesgasse 149, 8055 Graz, Austria., Rinnerhofer S; Center for Occupational Medicine AMEZ, Hergottwiesgasse 149, 8055 Graz, Austria., Wultsch G; Center for Occupational Medicine AMEZ, Hergottwiesgasse 149, 8055 Graz, Austria.; Medical University of Graz, Auenbruggerplatz 2, 8036 Graz, Austria., Birnbaumer P; Institute of Human Movement Science, Sport and Health, University of Graz, Max-Mell-Allee 11, 8010 Graz, Austria., Hofmann P; Institute of Human Movement Science, Sport and Health, University of Graz, Max-Mell-Allee 11, 8010 Graz, Austria.
Jazyk:	angličtina
Zdroj:	Journal of functional morphology and kinesiology [J Funct Morphol Kinesiol] 2020 Aug 25; Vol. 5 (3). Date of Electronic Publication: 2020 Aug 25.
DOI:	10.3390/jfmk5030066
Abstrakt:	Long-term heavy physical work often leads to early retirement and disability pension due to chronic overload, with a need to define upper limits. The aim of this study was to evaluate the value of the first lactate threshold (LTP 1 ) as a physiological marker for heavy occupational work. A total of 188 male and 52 female workers performed an incremental cycle ergometer test to determine maximal exercise performance and the first and second lactate (LTP 1 ; LTP 2 ) and ventilatory thresholds (VT 1 ; VT 2 ). Heart rate (HR) recordings were obtained during one eight-hour shift (HR 8h ) and oxygen uptake was measured during 20 minutes of a representative work phase. Energy expenditure (EE) was calculated from gas-exchange measures. Maximal power output (P max ), maximal oxygen consumption (VO 2 max ) and power output at LTP 1 and LTP 2 were significantly different between male and female workers. HR 8h was not significantly different between male and female workers. A significant relationship was found between P max and power output at LTP 1 . HR 8h as a percentage of maximum HR significantly declined with increasing performance (P max :r = -0.56; p < 0.01; P LTP1 :r = -0.49; p < 0.01). Despite different cardio-respiratory fitness-levels; 95.4% of all workers performed their usual work below LTP 1 . It is therefore suggested that LTP 1 represents the upper limit for sustained heavy occupational work; which supports its use to determine work capability and assessing the limits of heavy occupational work.
Databáze:	MEDLINE
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