ABSTRACT
The purpose of this study was to determine the effect of melatonin ingestion on cardiopulmonary indices during rest, exercise and recovery period in female athletes. Heart rate [HR], blood pressure [BP] and maximal oxygen consumption [VO[2] max] were measured before and after ingestion of melatonin during exercise. Ten female basketball players [age 21.8 +/- 1.135 year, height 171.1 +/- 1 cm.676, weight 61.3 +/- 1.693kg], who were playing in Shiraz basketball league, were selected for this study based on the regularity of their menstrual cycle in the last 3 month. They all were homogenized according to their chronotype and had not any kind of disease. They performed the protocol at luteinizing phase of their menstrual cycles in two separate days with 72 hours interval at 11: 30 min in the morning. HR, BP and VO[2] max were measured at the first day. To assess their VO[2] max and other factors under study during exercise, they performed Bruce treadmill protocol to exhaustion and all above factors were measured during exercise either. At the second stage, 72 hrs after the ingestion of 10 mg melatonin, the HR, BP and VO[2] max were measured 30 minutes after ingesting supplement. The same procedure followed for exercise and recovery stages. Paired-samples T test used for data analysis [alpha = 0.05]. HR decreased significantly after ingesting melatonin during exercise [p=0.0001]. Ingesting melatonin did not affect resting BP but it significantly decreased BP during exercise and recovery. Furthermore, ingesting 10 mg of melatonin before exercise led to significant increase of subjects VO[2] max [p=0.0001]. The finding of this study shows that ingesting melatonin decreases HR, BP and BT during rest, exercise and recovery moreover it increases VO[2] max. In other term it increases endurance performance especially in warm environments. Then, athlete and coaches could use melatonin ingestion as a method to pre-cooling, modulating applied stresses to cardio respiratory system during exercise in warm environments, improve their endurance performance and increase efficacy of recovery period