Blood lactate threshold and type II fibre predominance in patients with exertional heatstroke

Yaw Don Hsu, Wei Hwa Lee, Ming Key Chang, Shang Der Shieh, Wen Long Tsao

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23 Citations (Scopus)


Objectives - Severe damage to skeletal muscle is usually seen in patients with exertional heatstroke. Thirty seven young military recruits with exertional heatstroke in Taiwan from 1992 to 1995 were studied to evaluate changes in muscle pathology and blood lactate with exercise. Methods - A biopsy sample of the vastus lateralis was taken from recruits within 10 days of the initial presentation. Results were compared with those from 15 controls matched for age and sex. During the recovery period, 90-150 days after exertional heatstroke, 29 patients participated in a constant work load test on the treadmill to assess their blood lactate threshold, and a second biopsy sample was taken. Each biopsy was examined histologically for pathology, distribution of fibre types, and fibre diameter. Results - Twenty four of the 37 patients with exertional heatstroke developed rhabdomyolysis and 18 of these had type II fibre predominance in their muscle biopsy. The patients with type II fibre predominance had a higher tendency to develop rhabdomyolysis (χ2 = 6.84, P < 0.01). The time required to reach a blood lactate threshold during a constant treadmill work load after recovery was significantly shorter in the patients with exertional heatstroke who had type II fibre predominance (P < 0.01). There was a positive correlation between the highest value of blood lactate and the percentage of type II fibres in all tested subjects (r = 0.82, P < 0.01). Conclusion - Patients with type II fibre predominance are more susceptible to exertional heatstroke and tend to have a higher blood lactate concentration and a shorter time to reach blood lactate threshold under a treadmill load test.

Original languageEnglish
Pages (from-to)182-187
Number of pages6
JournalJournal of Neurology Neurosurgery and Psychiatry
Issue number2
Publication statusPublished - Feb 1997
Externally publishedYes


  • Blood lactate threshold
  • Exertional heatstroke
  • Type ii fibre predominance

ASJC Scopus subject areas

  • Clinical Neurology
  • Psychiatry and Mental health
  • Surgery


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