Effects of Exercise Training Intensity on Pancreatic β-Cell Function
Article Figures & Tables
Figures
- Figure 1
The effects of exercise amount and intensity on changes in DI (A), Si (B), and AIRg (C) are shown. Data are means ± SE. All P <0.10 for group comparisons are reported. For low amount/moderate intensity (n = 57); low amount/vigorous intensity (n = 58); high amount/vigorous intensity (n = 64).
Tables
- Table 1
Exercise prescription adherence by group and substrate use
Low amount/moderate intensity Low amount/vigorous intensity High amount/vigorous intensity n 57 58 64 Prescription and actual exercise dose Intensity (% peak oxygen consumption) 40–55% 65–80% 65–80% Prescription amount (miles/week)* 12 12 20 Prescription amount (kcal/week) 1,220 ± 212 1,230 ± 177 2,020 ± 307 Prescription time (min/week) 201 ± 37 125 ± 28 207 ± 44 Adherence (%) 88 ± 14 90 ± 12 84 ± 15 Actual amount (miles/week)† 10.6 10.8 16.8 Actual time (min/week)‡ 176 ± 36 113 ± 28 172 ± 41 Frequency (sessions/week) 3.5 ± 0.8 2.9 ± 0.5 3.6 ± 0.8 Respiratory exchange ratio 0.907 ± 0.05§ 0.960 ± 0.06 0.961 ± 0.04 Fat utilization Energy from fat (%) 30.2% 12.6% 12.6% kcals from fat (kcal) 368 155 255 -
Data are means ±SD.
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↵*Prescription amount is presented as the approximate number of miles/week that are calorically equivalent to the prescribed kcal/week of 14 kcal · kg body wt−1 · week−1 for the low-dose groups and 23 kcal · kg body wt−1 · week−1 for the high-dose group.
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↵†Actual amount = prescription amount × adherence for each group (therefore no SD).
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↵‡Actual time = prescription time × adherence for each subject. Respiratory exchange ratios were obtained during the submaximal exercise bout that was performed to determine the correct exercise intensity (i.e., 40–55% for the moderate-intensity group and 65–80% for the vigorous-intensity groups).
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↵§Respiratory exchange ratio for the moderate-intensity group was significantly different from both vigorous groups (P < 0.0005).
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- Table 2
Baseline and change scores for DI, AIRg, Si, metabolic variables, body weight, and body composition variables by group
n (men/women) Control Low amount/moderate intensity Low amount/vigorous intensity High amount/vigorous intensity 58 (30/28) 57 (30/27) 58 (33/25) 64 (38/26) Baseline Change P Baseline Change P Baseline Change P Baseline Change P DI (× 10−5 min−1) 1,562 ± 1,444 −65 ± 893 NS 1,270 ± 1,147 742 ± 1,680 0.002 1,533 ± 1,362 255 ± 1,023 0.063 1,305 ± 1,121 255 ± 688 0.004 AIRg (pmol/l) 490.6 ± 431 22 ± 233 NS 457.3 ± 334 −10 ± 207 NS 445.5 ± 353 −43 ± 216 0.14 505.6 ± 427 −77 ± 218 0.007 Si (× 10−5 min/pmol) 3.5 ± 2.1 −0.35 ± 1.7 0.12 3.1 ± 2.2 1.7 ± 2.5 <0.0001 3.7 ± 2.1 0.8 ± 1.8 0.001 3.2 ± 2.5 1.1 ± 2.1 <0.0001 Fasting glucose (mg/dl) 91 ± 11 3.2 ± 8 0.005 94 ± 9 −0.1 ± 9 NS 93 ± 8 1.2 ± 9 NS 94 ± 10 0.5 ± 10 NS Fasting insulin (μU/ml) 8.5 ± 4.3 0.9 ± 3.3 0.04 10.3 ± 8.1 −2.5 ± 5.6 0.002 8.8 ± 5.9 −1.5 ± 4.1 0.008 9.6 ± 5.6 −1.3 ± 3.3 0.002 HOMA (mg/dl × μU/ml) 2.0 ± 1.2 0.28 ± 0.8 0.011 2.5 ± 1.9 −0.58 ± 1.4 0.003 2.1 ± 1.6 −0.36 ± 1.1 0.014 2.3 ± 1.4 −0.30 ± 0.9 0.009 Triglycerides (mg/dl) 147 ± 71 5 ± 43 NS 171 ± 108 −35 ± 76 0.002 143 ± 67 −16 ± 49 0.02 155 ± 84 −21 ± 50 0.002 Body mass (kg) 88 ± 14 0.88 ± 2.4 0.007 87 ± 15 −0.81 ± 2.4 0.012 88 ± 13 −0.96 ± 2.3 0.003 88 ± 13 −0.15 ± 2.7 <0.0001 Visceral fat (cm2) 163 ± 66 13 ± 29 0.003 174 ± 77 −2.1 ± 30 NS 158 ± 56 −4.6 ± 36 NS 168 ± 72 −12 ± 35 0.018 Vo2 peak (ml · kg−1 · min−1) 27 ± 6 −0.7 ± 2 0.03 27 ± 6 1.8 ± 2 <0.0001 29 ± 6 3.4 ± 3 <0.0001 28 ± 5 5.0 ± 3 <0.0001 -
Data are means ± SD. Homeostasis model assessment (HOMA) [(fasting glucose × fasting insulin)/22.5] (indicator of insulin sensitivity during fasting conditions). NS, P > 0.30 and therefore not significant. All other P values (< 0.30) are shown.
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