Acute effect of 30 min of accumulated versus continuous brisk walking on insulin sensitivity in young Asian adults

The present study compared the acute effect of 30 min of accumulated versus continuous brisk walking on insulin sensitivity estimated in the fasted state and after an oral glucose tolerance test (OGTT) in young, healthy Asians. Twenty-five healthy participants (12 males) were provided an OGTT the morning after: (i) accumulating three 10 min bouts of walking the previous evening; (ii) walking continuously for 30 min the previous evening or; (iii) resting the previous evening. Blood samples were taken in the fasted state and for 2 h post-OGTT. Insulin sensitivity was estimated from fasting blood glucose and insulin using the quantitative insulin sensitivity check index (QUICKI) and in response to the OGTT using an insulin sensitivity index (ISI-Matsuda). Fasting insulin was lower after continuous (P = 0.006) but not accumulated (P = 0.371) walking versus rest and did not differ between walking trials (P = 0.554). Similarly, QUICKI [Accumulated 0.381 (0.026) vs. Continuous 0.388 (0.029) vs. Rest 0.371 (0.031)] improved only with continuous (P = 0.006) and not accumulated walking (P = 0.255) compared with rest. There was a significant difference in ISI-Matsuda among groups [Accumulated 7.07 (3.04) vs. Continuous 7.29 (2.81) vs. Rest 6.14 (2.46), P = 0.050] with a Bonferroni t test suggesting this was between continuous walking and rest (P = 0.081). These findings demonstrate that 30 min of brisk walking is sufficient to improve insulin sensitivity in healthy, young Asians but only continuous and not accumulated walking provides this benefit. Further studies are needed to determine if accumulated and continuous exercise have different chronic effects on insulin sensitivity.