Aging, Resistance Training, and Diabetes Prevention

Table 1

Randomized controlled trials >1 month in duration investigating the effect of resistance training on diabetes-related outcomes among nondiabetic middle-aged and older adults^†.

Source	Study design	Study duration	RT protocol	Study population	Primary findings
Traditional Weight Training only*
Iglay et al. [27]	RCT (𝑛=36): RT + 0.9/g/kg/d protein intake, 𝑛=16; RT + 1.2 g/kg/d, 𝑛=16	3 months	3x week, 8 machine exercises, 2 sets 8 reps + one set to voluntary fatigue at high intensity	Healthy individuals, aged 60–62 yrs.	↓ glucose OGTT AUC 25–28% with RT, no differences between diet groups.
Onambélé-Pearson et al. [110]	RCT (𝑛=30): LI (~40% 1RM), 𝑛=18; HI (~80% 1RM), 𝑛=12	3 months	3x week, 6 exercises using therabands, progressing from 8–11 reps and 2–4 sets, different intensity groups: HI versus LI	Sedentary individuals, aged 55–80 yrs.	↑ fasting plasma glucose (4.8 ± 0.19 to 5.51 ± 0.08 mmol/L) in HI group, no change in plasma glucose for LI, no change in plasma insulin for either group.
Zachwieja et al. [31]	RCT (𝑛=15): RT + GH injections,; 𝑛=6; RT only, 𝑛=9	4 months	4x week, 9 machine exercises, 4 sets, 4–10 reps at high intensity.	Healthy men, aged 64–75 yrs.	↑ in glucose disappearance rate (3.0 ± 0.3 to 4.0 ± 0.4 mg/100 mL/min minimal model of glucose kinetics, IVGTT) with RT only
RT + AT (either alone or combined)
Ahmadizad et al. [79]	RCT (𝑛=24): AT, 𝑛=8; RT, 𝑛=8; Control, 𝑛=8	3 months	3x week, circuit weight training, 11 machine exercises, 4 sets, 12 reps, at moderate intensity with 30 sec. rest between exercises.	Healthy men, aged 35–48 yrs.	↓ HOMA-IR 35.7 and 38.5% after AT and RT respectfully; no differences between groups.
Smutok et al. [109]	RCT (𝑛=37): RT, 𝑛=14; AT, 𝑛=13; Control, 𝑛=10	4.5 months	3x week, 11 machine exercises, 2 sets, 12–15 reps at moderate intensity.	Men at risk for CHD with either abnormal glucose tolerance, dyslipidemia, or hypertension, aged 41–59 yrs.	↓ plasma glucose at 60, 90, and 120 minutes after glucose ingestion with RT; ↓ plasma glucose at 90 and 120 min after glucose ingestion with AT. ↓ fasting glucose with RT, no changes with AT. Insulin OGTT AUC ↓ 24% for AT and 21% for RT, no changes in control.

*Traditional Weight Training= any muscle strengthening exercises using resistance training machines/equipment, free weights (e.g., dumbbell, barbell) or therabands.
^†Abbreviations used: AT: Aerobic training, AUC: Area under curve, GH: Growth Hormone, HI: High intensity, HOMA: Homeostasis model assessment, IVGTT: Intravenous glucose tolerance test, IR: Insulin Resistance, LI: Low intensity, OGTT: Oral glucose tolerance test, Reps: Repetitions, RCT: Randomized controlled trial, RT: Resistance training.