Evidence of histamine release in response to both aerobic and resistance exercise: histamine metabolites as biomarkers

Histamine released within skeletal muscle facilitates sustained postexercise vasodilation and contributes to the development of training adaptations. Quantifying the histamine response is challenging because histamine is rapidly broken down and metabolized. Thus, we explored the use of histamine’s metabolites, 1-methylhistamine and 1-methylimidazole acetic acid, as biomarkers of the histamine response to exercise. We hypothesized that plasma concentrations and urinary production of these metabolites would increase following aerobic and resistance exercise. Twelve (1 female, 11 male) participants (VO 2peak : 51.9±6.9 mL·kg -1 ·min -1 ; back squat 1-repetition maximum, 1-RM: 1.59±0.26 kg/bodyweight) completed two separate exercise sessions: Aerobic (30 min of cycling at 70% VO 2peak ) and resistance (6 sets of 10 repetitions of back squats at 10-RM). Femoral artery blood flow was measured, and blood samples were obtained before, immediately after, and throughout 2 h of postexercise recovery. Urine was collected 24 h before exercise, from the start of exercise until 2 h after exercise, and for 24 h after exercise. Plasma concentrations of 1-methylhistamine and 1-methylimidazole acetic acid increased following both exercise sessions ( p<0.05). Likewise, urine production rates of 1-methylhistamine and 1-methylimidazole acetic acid increased following both exercise sessions ( p<0.05). Further, receiver operating characteristic analysis for 1-methylimidazole acetic acid found strong evidence that urine production rates correctly discriminate between conditions (likelihood ratio 12, p<0.01; area under the curve 0.80, p<0.01). Thus, urine production rates of 1-methylhistamine and 1-methylimidazole acetic acid demonstrate utility as a biomarker of the histamine response to exercise.