TSAC Report 33 | Page 9

VERY LONG TRAUMATIC BRAIN INJURY EFFECTS OF MILD ARTICLE TITLE GOES HERE AND TAKES UPEXERCISE, AND RECOVERY ON ANABOLIC HORMONES, LOTS AND LOTS OF ROOM anabolic processes such as protein synthesis and glycogen uptake (28). Thus, reduced GH concentrations will likely have a negative impact on the concentration of circulating IGF-1 (27). Like GHD, suppressed testosterone concentrations have been reported to occur in those who have suffered a TBI (16). Testosterone is an anabolic hormone that modulates lean body mass, physical performance, and recovery (19). Additionally, testosterone also functions to increase protein synthesis, regulate body composition, improve muscle strength, and increase bone density (7,10). Further, low testosterone concentrations have been reported to either transiently or permanently occur in contact sport athletes following TBI. A case study by Tanriverdi et al. detailed a transient decrease in testosterone of an amateur kick boxer after suffering a head trauma (34). Another case study by Auer et al. detailing hypogonadism in a 27-year-old soccer player further suggests that multiple mTBIs adversely affect testosterone concentrations, and that pituitary evaluation is warranted in athlete populations that have suffered mild, but frequent, repeated head trauma (2). Chronic suppression of GH and testosterone concentrations in tactical athletes may have deleterious consequences on exercise capacity and recovery and will likely impact performance of physically demanding occupational tasks. Tactical athletes must be physically prepared to perform occupational tasks, underscoring the importance of prescribing an appropriate physical training program, performing ongoing physical assessments, and monitoring recovery status. Highintensity exercise programs place a great amount of physiological stress on tactical athletes and frequent exercise bouts with limited recovery will result in plateaued or reduced performance (18). Thus, adequate recovery is essential for exercise progression, injury mitigation, and expeditious return to duty—necessitating careful monitoring of recovery status by the tactical facilitator (4). However, exercising too soon following an mTBI injury is contraindicated, and can result in re-injury and/or delayed recovery whereby concussion symptoms return (13). Once mTBI symptoms have resolved, a graded resumption of premorbid activity is widely cited in the athletic and military literature as the recommended approach to re-establishing exercise routines following mTBI. However, this timeframe is highly individualized, ranging from days to months and should only begin after the tactical athlete has been cleared by a license