Changes in Salivary and Plasma Markers during and Following Short-Term Maximal Aerobic Exercise Assessed during Cognitive Assessment

This study assessed multiple salivary and plasma markers before and after incremental short-term maximal aerobic exercise and in a non-exercising control in conjunction with cognitive testing. Subjects: Apparently healthy 18 - 30 years old low CVD risk females participated (n = 19). Methods: Subjects completed two conditions: 1) exercise: short maximal treadmill exercise and cognitive assessment pre- and post-exercise and, 2) non-exercise: with cognitive assessment timed to match testing in the exercising condition. Non-stimulated, timed salivary samples and venous blood were collected before and after exercise and after recovery. Results: Saliva: Over time α-amylase increased in both exercise and non-exercising conditions. Exercise had increases in α-amylase at time matched control points up to 36% greater than the non-exercising conditions. Following exercise and recovery from exercise α-amylase in-creased compared to baseline (ranging from 47% to 290%). Baseline cortisol was 33% higher than post-exercise and 59% higher than recovery irrespective of exercise. Plasma: NEFA was 50% higher at post-exercise and recovery compared to baseline without exercise and 36% higher at post-exercise and recovery compared to baseline with exercise. Glucose and lactate were, 18% and 50% higher respectively, after exercise compared to baseline and recovery with exercise. Post-exercise glycerol was 11% higher than recovery. Differences between Conditions: Post-exercise glucose and lactate were 20% and 40% higher respectively with exercise. Glycerol was 11% lower after exercise. Conclusions: We demonstrated that acute exercise coupled with cognitive task increased α-amylase levels, but not cortisol, potentially due to a differential stress response, but most likely due to the timing of sample collection.