Effect of One and Two Split Aerobic Exercise Sessions on Circadian Rhythm of Heart Rate and Blood Pressure

The present study investigated the circadian rhythm variations of heart rate and blood pressure due to 1 (60 minutes) and 2 split exercise sessions (2 × 30 minutes) a day. Fourteen healthy students from the University of Tabriz volunteered to participate in current study. Two groups of subjects in a crossover design were randomly allocated as group I (one session per day, twice a day) and vice versa for group II. Having completed the test (treadmill running with an intensity of 70 per cent of Maximum Heart rate), heart rate and blood pressure (both systolic and diastolic) were measured every two hours for 24 hours. Repeated measure (ANOVA) was used for analysis. Each of variables showed normal circadian rhythm. Compared to two split exercise sessions a day, one session a day demonstrated that the level of heart rate circadian rhythm has been set at a rate of five percent below. Circadian rhythm of systolic and diastolic blood pressure in the two split sessions compared with one session a day tended to be set at a lower level and higher level respectively. One aerobic exercise session compared to two split sessions a day with the same total time of exercise a day may decrease systolic blood pressure and heart rate within 24 hours following aerobic treadmill running exercise. Split exercise session could be an appropriate approach for increasing more calories and lowering blood pressure among health seekers while it may delay recovery for the next day training or competition for professional athletes.