AEROBIC FITNESS AND THE DIURNAL RHYTHM OF BLOOD-PRESSURE IN ADOLESCENTS

We examined the effects of aerobic fitness and race on the diurnal rhythm of blood pressure of 17S healthy adolescents who performed a cycle ergometer maximal exercise test while oxygen consumption was measured. A median split of maximum oxygen consumption for boys and girls separately classified them as either “more-fit” or “less-flt” subjects. Ambulatory blood pressure recordings were also performed, and the data were analyzed for means while subjects were awake and asleep. Less-fit black boys had higher systolic pressures than more-fit black boys while awake (124 vs. 115 mm Hg; <0.009) and asleep (117 vs. 109; p<0.001). Less-flt black boys also had higher systolic pressures than less-flt white boys while awake (114; p <0.002) and asleep (105; p< 0.001), and they had higher systolic pressures than more-fit white boys while asleep (105; p<0.01). Less-fit black girls had higher systolic pressures than more-fit black girls while awake (116 vs. 109; p<0.004) and asleep (109 vs. 100;p<0.001). Less-fit black girls also had higher diastolic pressures than more-fit black girls while awake (71 vs. 66; p<0.002) and asleep (66 vs. 61; p< 0.001). In addition, less-fit black girls had higher systolic pressures than more-fit white girls while asleep (104; p<0.05), higher diastolic pressures than more-fit white girls while awake (68; p<0.05) and asleep (60; p<0.006), and higher diastolic pressures than less-flt white giris while asleep (61; p <0.001). These findings indicate that fitness influences ambulatory blood pressure profiles, particularly in black adolescents. © 1990 American Heart Association, Inc.