A-15P Free Communication/Poster Obesity
Training with multiple short bouts of exercise may be effective for improving some measures of health and fitness. Little is known about the acute effects of fractionalized exercise.
We compared the effects of continuous vs fractionalized exercise (Ex) on insulin, blood pressure (BP) and heart rare (HR) responses in lean (L) and obese (O) young males (n = 8 L, age = 23.3 yr; ht = 179.5 cm; wt = 76.3 kg, BMI = 23.7, VO2 peak = 38.3 ml/kg/min; n = 8 O, age = 30.6 yr; ht = 177.3 cm; wt = 103.6 kg, BMI = 33.3, VO2 peak = 28.5 ml/kg/min).
Subjects were admitted to the General Clinical Research Center on 3 randomly assigned occasions: control (C), one 30 min bout of Ex (0900–0930h, 1X30) and three 10 minute bouts of Ex (0920–0930h, 1320–1330h, 1520–1530h, 3X10) (Ex intensity = 50% of the difference between lactate threshold and peak). Identical meals were served at 1000h, 1400h, and 1800h. Insulin was measured at 0700h (fasting), hourly from 0900–2100h and at 0700h the next day (fasting). BP and HR were measured hourly from 0900 h-2100h. Data were analyzed with 2 way REANOVA with multiple comparison adjustment.
O had higher insulin concentrations than L throughout the day and a greater insulin response post-prandially (P < 0.05). Ex had no effect on insulin concentrations. HR was higher immediately prior to and 30 min after Ex (P < 0.05). No other HR differences were observed. The morning bouts of Ex had no effect on BP. The 3×10 Ex at 1320–1330h resulted in a reduction in BP for 2-h post exercise in both L and O (P < 0.05). The 3×10 Ex at 1520–1530h resulted in an initial reduction in BP in both L and O followed by a continued reduction in L and an elevation over time in O (2-way interaction, P < 0.05).
Fractionalized Ex may have utility for BP reduction in some young males. Changes in BP after fractionalized exercise may be related to an interaction between obesity status and the diurnal variation in BP. Supported in part by a NIH grant to the GCRC RR00847