Sweat Science: How Different Exercises Dramatically Alter Your Blood Sugar

Exploring the glycemic impact of strength training, high-intensity resistance training, and HIIT

10 min read October 2023 Exercise Science

The Glucose Rollercoaster

Your bloodstream is a busy highway where glucose vehicles transport essential energy to your cells. In type 2 diabetes, the off-ramps become clogged, leaving too many glucose vehicles idling in traffic.

This metabolic gridlock affects over 422 million people worldwide, with numbers projected to reach 552 million by 2030 3 . For decades, doctors have prescribed exercise as a primary treatment to unclog these metabolic off-ramps.

Did You Know?

Not all exercise is created equal when it comes to blood sugar management. Recent scientific investigations have revealed fascinating differences between various exercise modalities.

Research now shows dramatic variations in how strength training, high-intensity resistance training, and high-intensity interval training impact our glucose metabolism. The results might surprise you and could revolutionize how we approach exercise prescription for metabolic health.

Understanding the Glucose-Exercise Connection

What Is Diabetes Really?

Type 2 diabetes isn't just about "high blood sugar"—it's a complex metabolic disorder characterized by:

  • Insulin resistance (cells don't respond properly to insulin) 7
  • Pancreatic β-cell dysfunction (body can't produce enough insulin)

This impaired insulin action leads to elevated blood glucose levels that damage organs and tissues throughout the body.

The Exercise Prescription

Exercise improves glucose metabolism through multiple mechanisms:

  1. Immediate effects: Muscle contractions stimulate glucose uptake independent of insulin 7
  2. Long-term adaptations: Regular exercise increases muscle mass and improves insulin sensitivity
  3. Metabolic efficiency: Exercise enhances mitochondrial function and metabolic flexibility

The American Diabetes Association recommends at least 150 minutes per week of moderate-to-vigorous aerobic exercise plus two sessions of resistance training 3 .

Spotlight on a Groundbreaking Case Study

A 2021 study published in the journal Anthropology directly compared the acute effects of three different exercise modalities on glycemic behavior in a type 2 diabetic individual 1 .

Participant Profile
  • Age 57 years
  • Body Mass 83 kg
  • BMI 26.2 kg/m²
  • Diabetes Duration 32 years
Study Protocols
1
Strength Training (ST)
3 sets of 8-12 reps at 60% 1RM
2
High-Intensity Resistance Training (HIRT)
3 sets of 6 reps at 80% 1RM with 20s rest
3
High-Intensity Interval Training (HIIT)
4 intervals of 30s cycling with 4min rest

Methodological Breakdown

The researchers employed a meticulous approach to ensure reliable results. The study followed a six-visit protocol over several weeks 1 :

Visit 1

Informed consent, medical history review, and anthropometric measurements

Visit 2

10-repetition maximum testing to establish baseline strength levels

Visit 3

HIIT protocol familiarization

Visits 4-6

Implementation of the three different exercise protocols in random order

Final visit

Follow-up measurements

Revealing Results: HIIT Emerges as Champion

Glycemic Reduction Data

The results demonstrated clearly divergent effects among the three exercise modalities. While all three approaches reduced blood glucose levels, the magnitude and timing of these reductions varied substantially 1 :

Strength Training (ST)
23.63%

Maximum glucose reduction at 30 minutes post-exercise

HIRT
14.95%

Peak reduction at 20 minutes followed by a slight rebound

HIIT
38.89%

Maximum reduction at 20 minutes with sustained effects

Comparative Analysis

What makes these findings particularly significant is that HIIT produced superior results despite requiring less total time commitment. The HIIT protocol involved just 2 minutes of intense exercise dispersed over approximately 23 minutes including rest periods, while the resistance training protocols required longer engagement periods 1 .

This time efficiency addresses a critical barrier in exercise adherence—the perceived lack of time—suggesting that HIIT might offer a practical solution for those struggling to meet traditional exercise recommendations .

Practical Applications: From Lab to Life

Implementing Exercise for Metabolic Health

Based on the accumulating evidence, including the featured case study, here are practical recommendations for using exercise to improve glycemic control:

  • Prioritize intensity over duration: Brief, vigorous exercise appears particularly effective
  • Consider timing: Post-meal exercise may help blunt glucose spikes 2
  • Combine modalities: While HIIT appears superior, resistance training provides important long-term benefits
  • Find practical opportunities: Bodyweight HIIT can be performed anywhere
  • Progress gradually: Build intensity gradually over weeks to adapt and reduce injury risk
Sample HIIT Protocol Based on Research
Warm-up

3-5 minutes light activity

Intervals

4-10 reps of 30-60s high intensity

Recovery

1-4 minutes light activity between intervals

Cool-down

2-3 minutes gentle movement

Conclusion: Moving Toward Better Metabolic Health

The compelling case study provides a microcosm of the broader scientific understanding about exercise and metabolic health.

While all exercise benefits glucose metabolism, high-intensity interval training emerges as particularly potent for acute glucose reduction—a finding consistent across multiple study designs and populations 1 3 4 .

These findings don't diminish the value of other exercise forms but suggest that incorporating some high-intensity intervals might provide disproportionate metabolic advantages relative to time invested.

Knowing that just 10 minutes of interval training can lower my blood sugar as much as 30 minutes of continuous walking changes everything—I can always find 10 minutes.

As research continues to evolve, we move closer to personalized exercise prescriptions optimized for each unique metabolism. For now, the evidence strongly suggests that when it comes to blood sugar management, how you exercise may be just as important as how much you exercise.

References