Fatigue-related biomarkers in operators of special operations forces and their correlation with occupational specialties: a pilot study

Abstract

Objective To investigate the status of fatigue in the army special operations forces (SOF) and its relationship with occupational specialties. Methods A total of 203 operators at special positions were recruited from SOF divisions. Their fast venous blood and urine samples were collected in the next morning after regular military training. Hemoglobin (HB), blood urea nitrogen (BUN), urea acid (UA), creatine (CRE), creatine phosphokinase (CPK), lactic dehydrogenase (LDH) and microscale albuminuria (MAU) were measured and evaluated according to medical reference ranges and suitable restored limits recommended by National Bureau of Sports, so as to reflect the status of fatigue. The levels in the SOF group were compared to our data of HB, CRE, CPK and LDH levels in 162 non-SOF soldiers collected 7 years ago. The differences of the 7 biomarkers among the different SOF positions, and the correlation of these biomarkers with the occurrence of training-related injuries (strain and laceration) were analyzed. Results In the SOF operators, 17.2%, 2.5%, 34.0%, 0%, 78.3%, 14.3% and 21.1% of them had abnormalities when compared with the medical reference ranges for HB, BUN, UA, CRE, CPK and LDH, respectively, and even 32.5%, 0.0%, 57.1% and 11.3% of them separately had their HB, BUN, CPK and LDH values beyond the restored values in professional athletes after exercise. There were more SOF operators having abnormal HB and UA values than the soldiers from non-SOF force (proportions beyond medical reference ranges for HB: 1.3% and UA: 6.8%, and 12.3% of them beyond the restored value)(P < 0.001). Significant differences were seen in the CPK, LDH and MAU values among the operators of different SOF positions, and scouts had higher levels in multiple biomarkers. The CPK level was positively correlated with UA (P=0.013), LDH (P < 0.001) and MAU (P=0.015), and that of CRE was with BUN (P < 0.001) and UA (P < 0.001). Among the SOF operators with repetitive strain or laceration injuries, they had higher proportions of CPK and LDH abnormalities (both P < 0.05). Conclusion There are large proportion of the SOF operators having abnormal multiple biomarkers for fatigue status when compared with the medical references and the returned values in professional athletes after exercise. The fatigue status of scouts is at a high level in all specialties, and CPK and LDH may have potential to monitor the fatigue status in them.

Keywords

• special operation
• training injury
• fatigue
• military training
• biomarkers