Immunoendocrine responses of male spinal cord injured athletes to 1-hour self-paced exercise: pilot study

This study examined the effect of a 1 h, self-paced handcycling time trial on blood leukocytes, mucosal immunity, and markers of stress in paraplegic athletes. Nine male paraplegic athletes (spinal injury level thoracic 4-lumbar 2) performed 1 h of handcycling exercise on a standard 400 m athletics track. Heart rate (HR) was measured continuously during exercise, and a retrospective rating of perceived exertion (RPE) was obtained immediately after. Venous blood and saliva samples were collected immediately before exercise (Pre-Ex), after exercise (End-Ex), and 1 h postexercise (1-h Post). The athletes completed mean +/- standard error of mean 22.4 +/- 1.1 km cycling at HR 165 +/- 2 beats/min, RPE 15 +/- 1, and blood lactate 7.9 +/- 2.5 mmol/L. Total leukocytes increased 72% and neutrophils increased 74% End-Ex; both remained elevated at 1-h Post (both p < 0.05). Lymphocytes increased 53% and natural killer cells increased 175% End-Ex (both p < 0.05), but returned to near baseline levels 1-h Post. Increases (p < 0.05) were observed End-Ex in alpha-amylase activity (p < 0.05), which returned to baseline at 1-h Post, but there was no significant change in saliva flow rate, salivary immunoglobulin A, or cortisol. These data confirm that 1 h of handcycling exercise elevated circulating leukocytes but had a minimal effect on mucosal immunity. These changes appear to be associated with alpha-amylase rather than cortisol.