Table 2.
Studies investigating the effects of physical activity and exercise on insulin in elderly subjects.
| Authors | Study Year | Sample Size | Age | Gender | Intervention | Main Findings |
|---|---|---|---|---|---|---|
| Seals et al. [33] | 1984 | 11 | 63 ± 1 y | Male and female | 12 months of endurance training (low-versus high-intensity program) | Improved insulin sensitivity and reduction in total AUC for insulin by 8–23% (by 8% after the low-intensity training program and by 23% after the high-intensity training program) |
| Seals et al. [61] | 1984 | 12 | 62 ± 1 y | Male | Self-reported physical activity | Lean older subjects had similar insulin levels when compared to younger subjects and statistically lower than the older untrained individuals |
| Hollenbeck et al. [62] | 1985 | 20 (13 inactive versus 7 active subjects) | 60–75 y | Male | Self-reported physical activity level | Better insulin resistance profile in older trained subjects |
| Craig et al. [42] | 1989 | 9 (cases versus 6 young controls) | 62.8 ± 0.7 y | Male | 12 weeks of progressive high-resistance training (weight lifting program with a three set, six to eight repetition protocol: 45–60 min of isotonic weight-conditioning exercise on Nautilus equipment and leg press, leg extension, leg curl, torso extension, bench press, pull down, pull over and horizontal arm adduction) | Reduction in insulin levels |
| Tonino [70] | 1989 | 11 | 60–80 y | Male | 12 weeks of physical training | Decrease in peripheral insulin resistance |
| Kahn et al. [34] | 1990 | 13 | 61–82 y | Male | 6 months of intensive endurance exercise training | Decrease of insulin levels |
| Increase of insulin sensitivity by 36% | ||||||
| Broughton et al. [63] | 1991 | 13 (cases versus 14 young controls) | 60 y and older | Male | Self-reported physical activity level | No significant differences |
| Poehlman and Danforth [71] | 1991 | 19 | 64 ± 1.6 y | Male | 8 weeks of endurance training program (cycling exercise) | No changes in insulin levels |
| Kirwan et al. [32] | 1993 | 12 | 65 ± 1 y [60–70 y] | Male | 9 months of endurance training | Reduction in fasting insulin |
| Improved insulin activity | ||||||
| Cononie et al. [75] | 1994 | 9 | 60–80 y | Male | Seven days of 50 min of exercise at 70% VO2max | Fasting plasma insulin levels and plasma insulin responses to an oral glucose challenge were reduced by 15% and 20% |
| DiPietro et al. [60] | 1998 | 16 (7 of which serving as controls) | 73 ± 1 y | Male and female | Moderate-intensity aerobic training, four times a week for 60-min sessions | Improvement in insulin resistance and glucose tolerance |
| Chadan et al. [54] | 1999 | 7 | 62–69 y | Female | Four bouts of physical activity on separate occasions at either a low (heart rate = 100 bpm) or moderate intensity (heart rate = 120 bpm) for either 25 or 50 min | Decrease by 35% in all experimental conditions |
| Evans et al. [35] | 2005 | 10 | 80.3 ± 2.5 y, 77–87 y | Male (n = 8) and female (n = 2) | 10–12 months of program (for a total of 108 exercise sessions) consisting in a supervised endurance exercise training comprising of 2.5 sessions/week, 58 min/session, at an intensity of 83% of peak heart rate | Improvement in insulin activity |
| Goulet et al. [36] | 2005 | 8 versus 14 younger controls | 62.3 ± 4.7 y | Female | Aerobic training (25–60 min sessions of running at 60–95% of maximal heart rate) three days per week during 6 months, with insulin resistance measured 3–5 days after the last training bout | No improvement in insulin resistance |
| DiPietro et al. [66] | 2006 | 25 | 73 ± 10 y | Female | Random allocation to high-intensity [80% peak aerobic capacity (VO2peak)] aerobic training, moderate-intensity (65% VO2peak) aerobic training, and low-intensity (stretching) placebo control (50% VO2peak) groups | Significant improvements only in the high-intensity training group |
| Bassami et al. [76] | 2007 | 13 | 60 y and older | Male | Three 30-min trials on a cycle ergometer at 50%, 60% and 70% VO2max and two other trials at 60% and 70% VO2max in which the total energy expenditure was equal to that for 30 min at 50% VO2max | No significant differences between groups |
| Fujita et al. [55] | 2007 | 13 | 70 ± 2 y | Male (n = 10) and female (n = 3) | Bout of aerobic exercise (45-min treadmill walk, 70% heart rate max) | Improvement in insulin resistance |
| Kodama et al. [56] | 2007 | 56 | 64 ± 6 y | Male (n = 14) and female (n = 42) | Low-intensity and low-volume exercise training (12-week exercise program, comprising of aerobic training and resistance training) | Decrease in insulin resistance by 21% |
| Dipietro et al. [37] | 2008 | 20 | 74 ± 5 y | Female | Random allocation into a high-volume, moderate-intensity aerobic (n = 12) and a lower-intensity resistance training (n = 8) groups 4 times per week for 45 to 60-min sessions over nine months | Not statistically significant changes in insulin levels in both groups |
| Dela et al. [72] | 2011 | 42 (20 of which serving as controls) | 60 y and older | Male and female | 12 weeks of alpine ski training | Decrease in insulin concentration, decreased insulin resistance |
| Lira et al. [57] | 2011 | 14 | 70.32 ± 0.72 y | Male | Moderate training for 60 min/d, 3 day/w for 24 weeks at a work rate equivalent to the ventilatory aerobic threshold | Improvement in insulin concentration and insulin resistance |
| Mikkelsen et al. [64] | 2013 | 27 versus 22 young controls | NR | Male | Self-reported physical activity (n = 15 trained, n = 12 untrained) | Better insulin profile in trained subjects |
| Gando et al. [59] | 2014 | 807 | 58-59 y | Male and female | Physical activity was measured using a triaxial accelerometer worn for 28 days and summarized as light intensity (1.1–2.9 METs) or moderate to vigorous intensity (≥ 3.0 METs) | Light physical activity inversely associated with insulin resistance |
| Hwang et al. [67] | 2016 | 51 (16 of which serving as controls) | 65 ± 1 y [55-79 y] | Male and female | Randomly allocated to high-intensity interval training (n = 17) or to moderate intensity continuous training (n = 18) | Insulin resistance decreased by 26% only in the high-intensity interval training group |
| Chen et al. [68] | 2017 | 26 | 60–76 y | Male | Randomly allocated to the eccentric training or concentric training group (n = 13 per group), performing 30–60 eccentric or concentric contractions of knee extensors once a week. The intensity of the training program was progressively increased over a period of 12-weeks from 10% to 100% of maximal concentric strength for eccentric training and from 50% to 100% for the concentric training program | Statistically significant improvement of insulin sensitivity only after eccentric training |
| Herbert et al. [23] | 2017 | 22 (cases) versus 17 (controls) | 62 ± 2 y | Male | 6 weeks of high-intensity interval training | Moderate reduction in insulin levels |
| Robinson et al. [73] | 2017 | 26 | 60 y and older | Male (53.8%) | 12 weeks of high-intensity aerobic interval, resistance, and combined exercise training | Increased insulin activity and sensitivity, with effects more marked in the high-intensity aerobic interval group |
| Banitalebi et al. [74] | 2018 | 40 (12 of which serving as controls) | 67.35 ± 1.40 y | Female | Randomly allocated to a resistance followed by endurance training program (n = 12), endurance training followed by resistance training (n = 12), interval resistance-endurance training (n = 12) | No differences among the groups and no difference between before and after the intervention |
| Lithgow and Leggate [53] | 2018 | 14 | 64 ± 2 y | Male and female | Single bout of high intensity intermittent exercise | Insulin concentration during an OGTT elevated at 60 min when compared to the control trial |
| McGregor et al. [58] | 2018 | 1,454 | 65–79 y | Male and female | Light-intensity physical activity and moderate to vigorous intensity physical activity assessed during the Canadian Health Measures Survey | 2,000 steps/d can be sufficient to preserve insulin activity and sensitivity |
| Park et al. [65] | 2018 | 2,325 | 60–74 y | Male (n = 862) and female (n = 1,463) | Self-reported physical activity level | OR of developing insulin resistance 0.55 [95%CI 0.34–0.87] in men and 0.68 [95%CI 0.47–0.98] in women |
| Søgaard et al. [77] | 2018 | 22 | 63 ± 1 y | Male (n = 11) and female (n = 11) | High-intensity interval training three times/w for 6 weeks on a bicycle ergometer | Statistically significant improved insulin sensitivity |
| Ihalainen et al. [38] | 2019 | 92 randomly assigned to a group performing strength training one-, two-, or three-times-per-w and a non-training control group | 65–75 y | Male and female | Whole-body strength training using 2–5 sets and 4–12 repetitions per exercise and 7–9 exercises per session for 6 mo | No differences between groups and between before and after the intervention |
Abbreviations: AUC (area under the curve); CI (confidence interval); d (day); MET (metabolic equivalent task); min (minute); mo (month); NR (not reported); OGTT (oral glucose tolerance test); OR (odds-ratio); w (week); y (years).