A claim you hear on longevity podcasts

Can strength training and HIIT reverse insulin resistance?

The claim checked: Strength training and HIIT have a huge impact on reversing insulin resistance Hear it at 4:07

What do the studies say?

Leaning for

Most studies found resistance training lowered HbA1c, a long-term blood sugar measure, by 0.57 points in one pooled analysis; another called its effect small.

Computed from 10 studies that test this point, each judged by two readers, in full. 10 more studies are waiting for a full read and do not count yet.

What was said on the podcast?

“also exercise is really key if you exercise particularly strength training and high interval intensity training which is go really fast and then slow that has a huge impact on reversing insulin resistance”
Mark Hyman, The Dr. Hyman Show · 8 Strategies to Reverse Skinny-Fat Syndrome · 4:07 on YouTube
Comes up in 18 episodes of the show.
Point 1 of 2 Leaning for

Strength training has a huge impact on reversing insulin resistance

Agree 3

controlled trial · 2002 · landmark

“In conclusion, appropriately prescribed and supervised high-intensity resistance training proved both feasible and effective among high-risk older adults with type 2 diabetes, resulting in improved gylcemic and metabolic control.”

A randomized controlled trial of resistance exercise training to improve glycemic control in older adults with type 2 diabetes. Diabetes Care
Who: 62 community-dwelling Latino older adults (>55 y, mean 66) with type 2 diabetes of at least 3 years
PMID 12453982

other primary study · 2012

“The present study demonstrated that a short-term PRT leads to clinically important improvements in glycemic control, muscle strength and reduction of WC in middle-aged T2D subjects of Asian Indian ethnicity.”

Resistance Training Leads to Clinically Meaningful Improvements in Control of Glycemia and Muscular Strength in Untrained Middle-aged Patients with type 2 Diabetes Mellitus. N Am J Med Sci
Who: 48 untrained middle-aged (35-55 y, mean 44.7) Asian Indian adults with type 2 diabetes in New Delhi (35 men, 13 women)
PMID 22912941

controlled trial · 2024

“Twelve weeks of AT and RT induced large and very large training effects in FGF-21 responses.”

A Randomized Controlled Trial to Determine the Impact of Resistance Training versus Aerobic Training on the Management of FGF-21 and Related Physiological Variables in Obese Men with Type 2 Diabetes Mellitus. J Sports Sci Med
Who: 36 sedentary obese men aged 40-45 with type 2 diabetes (BMI >30, HbA1c >=6.5%, on metformin) in China
PMID 39228768

Partly agree 7

trial or observed group · 2004 · landmark

“In summary, we have reported that strength training, like endurance training, enhances insulin action in skeletal muscle in patients with type 2 diabetes.”

Strength training increases insulin-mediated glucose uptake, GLUT4 content, and insulin signaling in skeletal muscle in patients with type 2 diabetes. Diabetes
Who: 10 Caucasian patients with type 2 diabetes and 7 healthy men, ~61-62 y; one leg trained, other leg control
PMID 14747278

controlled trial · 2023 · landmark

“This study found that strength training led to a larger reduction in HbA1c levels (−0.44 percentage points) than aerobic training alone (−0.24 percentage points).”

Strength training is more effective than aerobic exercise for improving glycaemic control and body composition in people with normal-weight type 2 diabetes: a randomised controlled trial. Diabetologia
Who: Adults aged 18-80 with normal-weight type 2 diabetes (BMI <25, HbA1c 6.5-13.0%), median age 59, 60% men, 83% Asian, San Francisco Bay Area
PMID 37493759

controlled trial · 2015

“HOMA-IR improved significantly only after high intensity interval training, by -0.83 (95% confidence interval [CI], -1.45, -0.20), equal to 17%, with between-group difference (p = 0.014).”

Effects of High Intensity Interval Training and Strength Training on Metabolic, Cardiovascular and Hormonal Outcomes in Women with Polycystic Ovary Syndrome: A Pilot Study. PLoS One
Who: Women aged about 27 with polycystic ovary syndrome (BMI 26.7 +/- 6.0), not regularly training
PMID 26406234

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other primary study · 2019

“After the 16‐week intervention of LST training, HbA1c tended to decrease from 7.06 ± 0.46% to 6.82 ± 0.41% (P = 0.07; Table 2).”

Effects of low-intensity resistance training on muscular function and glycemic control in older adults with type 2 diabetes. J Diabetes Investig
Who: 10 older adults with treated type 2 diabetes (mean age 68.2 ± 9.7, 50% women), Tokyo; 9 completed
PMID 30175458

pooled analysis · 2011 · landmark

“Four articles (261 patients) demonstrated that structured resistance exercise training was associated with a decline in absolute HbA1c of 0.57% (95% CI, −1.14% to −0.01%; I2, 92.5%; P for heterogeneity <.001) as compared with control.”

Physical activity advice only or structured exercise training and association with HbA1c levels in type 2 diabetes: a systematic review and meta-analysis. JAMA
Who: adults with type 2 diabetes (mean ages about 52-69 y) in RCTs of at least 12 weeks
PMID 21540423

systematic review · 2018 · landmark

“Integrating the currently available data, our network meta-analysis indicated that combined exercise was as effective in reducing HbA1c as supervised aerobic and supervised resistance forms of exercise.”

Exercise training modalities in patients with type 2 diabetes mellitus: a systematic review and network meta-analysis. Int J Behav Nutr Phys Act
Who: Adults with type 2 diabetes (mean age 55-72) in RCTs
PMID 30045740

pooled analysis · 2022 · landmark

“We found a small significant effect of RT on HbA1c relative to control (WMD=−0.390, 95% CI −0.60 to −0.18, I 2 =69.20, p<0.001), with moderate-to-high heterogeneity (I 2 =69.198).”

Effect of resistance training on HbA1c in adults with type 2 diabetes mellitus and the moderating effect of changes in muscular strength: a systematic review and meta-analysis. BMJ Open Diabetes Res Care
Who: Adults with type 2 diabetes mellitus in RCTs across 19 countries
PMID 35273011

Disagree 0

None.

Point 2 of 2 Leaning for

HIIT has a huge impact on reversing insulin resistance

Most trials found interval training raised insulin sensitivity, by 17.6% in one; one found no gain, and one saw it fade after 4 days without exercise.

Computed from 10 studies that test this point, each judged by two readers, in full. 10 more studies are waiting for a full read and do not count yet.

Agree 5

controlled trial · 2008 · landmark

“In our study, AIT promoted insulin sensitivity and β-cell function more than CME.”

Aerobic interval training versus continuous moderate exercise as a treatment for the metabolic syndrome: a pilot study. Circulation
Who: Adults with WHO-defined metabolic syndrome (mean age 52.3 years, VO2max 34 ml/kg/min)
PMID 18606913

systematic review · 2019

“High-intensity interval training by adults, especially those with overweight and obesity classification, can improve insulin sensitivity, blood pressure, and body composition, comparable to those resulting from moderate-intensity continuous training.”

High-Intensity Interval Training for Cardiometabolic Disease Prevention. Med Sci Sports Exerc
Who: Adults with group mean ages ~20 to ~77, varied weight and health status, including overweight/obese and metabolic syndrome/type 2 diabetes
PMID 31095079

controlled trial · 2015

“However, in the T2D-group, HOMA-IR was significantly (p = 0.03) decreased (Fig 4) and HOMA-%β was significantly (p = 0.03) increased (Fig 5).”

High Intensity Interval Training Improves Glycaemic Control and Pancreatic β Cell Function of Type 2 Diabetes Patients. PLoS One
Who: 10 inactive type 2 diabetes patients (56±2 yrs) on oral agents and 13 matched healthy controls
PMID 26258597

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controlled trial · 2015

“The present study resulted in significant improvements in fasting blood glucose and IN sensitivity following three weeks interval training.”

High-intensity interval training: Modulating interval duration in overweight/obese men. Phys Sportsmed
Who: 25 overweight/obese men (BMI 25-45, age 38.3±11.5), without untreated diabetes
PMID 25913937

controlled trial · 2018

“High intensity training has stronger beneficial effects on physical fitness, basal respiratory exchange ratio and insulin sensitivity compared to continuous aerobic training in overweight/obese men.”

High intensity interval training is associated with greater impact on physical fitness, insulin sensitivity and muscle mitochondrial content in males with overweight/obesity, as opposed to continuous endurance training: a randomized controlled trial. J Musculoskelet Neuronal Interact
Who: 16 sedentary men with overweight/obesity at risk for type 2 diabetes, aged 42-57, BMI 28-36, HbA1c < 6.5%
PMID 29855444

Partly agree 4

controlled trial · 2020 · landmark

“However, when trained participants abstained from exercise for 4 days, insulin sensitivity returned to pretraining levels in both groups.”

Moderate-Intensity Exercise and High-Intensity Interval Training Affect Insulin Sensitivity Similarly in Obese Adults. J Clin Endocrinol Metab
Who: Inactive, otherwise healthy adults with obesity (age 31 ± 6 y, BMI 33 ± 3), weight held stable
PMID 32492705

controlled trial · 2015

“We found no significant difference between HIIT and MIT, but did demonstrate an overall 17.6% increase in insulin sensitivity from baseline to post-exercise training in all participants.”

High Intensity Interval- vs Moderate Intensity- Training for Improving Cardiometabolic Health in Overweight or Obese Males: A Randomized Controlled Trial. PLoS One
Who: Sedentary overweight or obese young men aged 17-22 (BMI 25-35) with normal fasting glucose
PMID 26489022

controlled trial · 2023

“Therefore, despite clinically meaningful improvements, severe insulin resistance persisted.”

High-Intensity Interval Training is Safe, Feasible and Efficacious in Nonalcoholic Steatohepatitis: A Randomized Controlled Trial. Dig Dis Sci
Who: 14 inactive adults aged 18-70 with biopsy-confirmed NASH (mean age 56, BMI 39, 64% with type 2 diabetes)
PMID 36538276

Show 1 more Show fewer

pooled analysis · 2025

“Results showed that LV-HIIT with reduced intensity and extended intervals was effective in improving glucose control, however FPI and insulin resistance measured by HOMA-IR were not improved.”

Effects of practical models of low-volume high-intensity interval training on glycemic control and insulin resistance in adults: a systematic review and meta-analysis of randomized controlled studies. Front Endocrinol (Lausanne)
Who: adults 18+ who were not trained athletes (normal weight, overweight/obese, pre-diabetic and type 2 diabetic; mean age 20-58), in randomized controlled studies of low-volume HIIT vs no-exercise control or moderate continuous training
PMID 39917538

Disagree 1

controlled trial · 2017

“Neither intervention significantly improved OGTT-derived measures of insulin sensitivity, glycaemic control measured using continuous glucose monitors, blood lipid profile or body composition.”

A comparison of the health benefits of reduced-exertion high-intensity interval training (REHIT) and moderate-intensity walking in type 2 diabetes patients. Appl Physiol Nutr Metab
Who: 16 men with type 2 diabetes (age 55 ± 5 y, BMI 30.6 kg/m2), not on insulin; 21 recruited, 5 dropped out
PMID 28121184

What else was said but not tested?

  • Exercise in general is key for skinny-fat syndrome

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