T M Mäkinen | PubMed Health

PubMed2000

Frostbite: occurrence, risk factors and consequences.

Frostbites affect the civilian northern population more commonly than thought earlier. Cumulative lifetime incidences may be as high as 44-68% for all types of frostbite. Incidences of frostbite have mainly been reported in association with military activities but occur also during occupational duties and in recreational situations. Frostbites often affect the extremities and especially the head region. Several different predisposing factors have been reported in relation to frostbites. These can be divided mainly into environmental, individual, behavioural and occasion-linked factors. Actual risk analyses have been conducted for a limited amount of these predisposing factors. Frostbites very often result in different functional disadvantages, some of which can lead to a temporary or permanent disability to work or carry out military duties, while others may impact negatively on occupational activities, or cause hospitalization and invalidity to varying degrees. Further, frostbites often cause sequelae lasting from a few weeks to a lifetime.

Absenteeism↗

PubMed1998

Submaximal exercise in the cold: does cooling potentiate the development of muscle injuries in the rat?

To test the effect of low ambient temperature on muscular strain and possible development of muscle injuries, male Sprague-Dawley rats (n = 35) were exercised at a speed of 15 m min-1 on a treadmill at a 6 degrees inclination for 1.5 h in a warm (22 degrees C) or a cold (-10 degrees C) environment. Blood and tissue samples were collected 0 and 48 h postexercise. Blood glucose, lactate, pyruvate, cortisol, epinephrine (E) and norepinephrine (NE) were determined to investigate the effect on energy metabolism. To estimate the degree of physical strain, possible muscle injury and regenerative processes of muscles in response to exercise in the cold, serum creatine kinase (CK), lactate dehydrogenase (LDH), muscle beta-glucuronidase and prolyl-4-hydroxylase (PH) activities were measured. In addition, histology of the hindlimb muscles m. soleus and m. tibialis anterior was examined. In general, the circulating level of metabolic substrates during exercise were unaffected by the exercise and independent of ambient temperature. Plasma cortisol increased significantly during exercise (P < 0.01), but was unaffected by the thermal strain. Of the myocellular enzymes, serum CK increased by 100% (P < 0.01) and LDH by 93% (P < 0.05) during exercise in the cold compared with exercise in warm, indicating a higher physical strain. However, exercise in the cold did not result in muscle injuries as judged by the unaltered muscular beta-glucuronidase, PH levels and muscle morphology. It is concluded that the exercise type and intensity used caused stress that was independent of the ambient temperature. In addition, the rats were able to maintain unaltered circulating levels of energy substrates also in the cold. Finally, exercise in the cold increased muscular strain but did not result in muscle injuries.

Animals↗