TY - JOUR
T1 - A 2-wk reduction of ambulatory activity attenuates peripheral insulin sensitivity
AU - Krogh-Madsen, Rikke
AU - Thyfault, John P
AU - Broholm, Christa
AU - Mortensen, Ole Hartvig
AU - Olsen, Rasmus H.
AU - Mounier, Remi
AU - Plomgaard, Peter
AU - van Hall, Gerrit
AU - Booth, Frank W
AU - Pedersen, Bente K
PY - 2010/5/1
Y1 - 2010/5/1
N2 - US adults take between ∼2,000 and ∼ 12,000 steps per day, a wide range of ambulatory activity that at the low range could increase risk for developing chronic metabolic diseases. Dramatic reductions in physical activity induce insulin resistance; however, it is uncertain if and how low ambulatory activity would influence peripheral insulin sensitivity. We aimed to explore if healthy, nonexercising subjects who went from a normal to a low level of ambulatory activity for 2 wk would display metabolic alterations including reduced peripheral insulin sensitivity. To do this ten healthy young men decreased their daily activity level from a mean of 10, 501 ± 808 to 1, 344 ± 33 steps/day for 2 wk. Hyperinsulinemic-euglycemic clamps with stable isotopes and muscle biopsies, maximal oxygen consumption (V̇o2 max) tests, and blood samples were performed pre- and postintervention. A reduced number of daily steps induced a significant reduction of 17% in the glucose infusion rate (GIR) during the clamp. This reduction was due to a decline in peripheral insulin sensitivity with no effect on hepatic endogenous glucose production. The insulinstimulated ratio of PAktthr308/total Akt decreased after step reduction, with a post hoc analysis revealing the most pronounced effect after 4 h of insulin infusion. In addition, the 2-wk period induced a 7% decline in V̇o2max (ml/min; cardiovascular fitness). Lean mass of legs, but not arms and trunk, decreased concurrently. Taken together, one possible biological cause for the public health problem of Type 2 diabetes has been identified. Reduced ambulatory activity for 2 wk in healthy, nonexercising young men significantly reduced peripheral insulin sensitivity, cardiovascular fitness, and lean leg mass.
AB - US adults take between ∼2,000 and ∼ 12,000 steps per day, a wide range of ambulatory activity that at the low range could increase risk for developing chronic metabolic diseases. Dramatic reductions in physical activity induce insulin resistance; however, it is uncertain if and how low ambulatory activity would influence peripheral insulin sensitivity. We aimed to explore if healthy, nonexercising subjects who went from a normal to a low level of ambulatory activity for 2 wk would display metabolic alterations including reduced peripheral insulin sensitivity. To do this ten healthy young men decreased their daily activity level from a mean of 10, 501 ± 808 to 1, 344 ± 33 steps/day for 2 wk. Hyperinsulinemic-euglycemic clamps with stable isotopes and muscle biopsies, maximal oxygen consumption (V̇o2 max) tests, and blood samples were performed pre- and postintervention. A reduced number of daily steps induced a significant reduction of 17% in the glucose infusion rate (GIR) during the clamp. This reduction was due to a decline in peripheral insulin sensitivity with no effect on hepatic endogenous glucose production. The insulinstimulated ratio of PAktthr308/total Akt decreased after step reduction, with a post hoc analysis revealing the most pronounced effect after 4 h of insulin infusion. In addition, the 2-wk period induced a 7% decline in V̇o2max (ml/min; cardiovascular fitness). Lean mass of legs, but not arms and trunk, decreased concurrently. Taken together, one possible biological cause for the public health problem of Type 2 diabetes has been identified. Reduced ambulatory activity for 2 wk in healthy, nonexercising young men significantly reduced peripheral insulin sensitivity, cardiovascular fitness, and lean leg mass.
U2 - 10.1152/japplphysiol.00977.2009
DO - 10.1152/japplphysiol.00977.2009
M3 - Journal article
SN - 8750-7587
VL - 108
SP - 1034
EP - 1040
JO - Journal of Applied Physiology
JF - Journal of Applied Physiology
IS - 5
ER -
