The Study
Plasma Sulphur-Containing Amino Acids, Physical Exercise and Insulin Sensitivity in Overweight Dysglycemic and Normal Weight Normoglycemic Men
This study found that when men exercised for 12 weeks, their blood chemicals changed at the same time their bodies got better at using sugar. But it doesn't prove that the chemical changes caused the improvement — they just happened together.
Analysis score
Maximum 90 for a randomized controlled trial.
Where the score came from
When men exercised regularly for 12 weeks, their bodies got better at using insulin to soak up sugar from the blood. This happened at the same time as some blood chemicals changed — especially a drop in cysteine and glutathione.
Where does this study sit?
Reviews of RCTs (Meta-analyses)
Max 100Randomized Trials
Max 90Reviews of Cohort Studies
Max 85Cohort Studies
Max 72Reviews of Case-Control Studies
Max 63Case-Control Studies
Max 58Cross-Sectional & Case Series
Max 50Expert Opinion
Max 559 / 100
Quality score
Participants are randomly assigned to treatment or control groups, minimizing bias. The gold standard for testing whether an intervention causes an effect.
Key takeaways
Summary
Based on the study abstract and findings.
- 1Yes — better insulin sensitivity means lower risk of type 2 diabetes, even in people already showing early signs of metabolic trouble.
- 2Insulin sensitivity improved by 45% on average; plasma cysteine dropped significantly and was the strongest predictor of improvement; mitochondrial genes in muscle and fat increased.
Score breakdown, methodology, conflicts of interest, evidence analysis & raw study data
Publication
Journal
Nutrients
Year
2018
Authors
Sindre Lee, T. Olsen, K. Vinknes, H. Refsum, H. Gulseth, K. Birkeland, C. Drevon
Related Content
Claims (6)
In men, consistent long-term exercise is linked to lower levels of plasma glutathione, alongside higher insulin sensitivity and increased activity of mitochondrial genes in muscle and fat tissue.
In men, a single session of intense physical activity causes a temporary rise in the blood levels of homocysteine, cystathionine, cysteine, glutathione, and taurine, reflecting immediate biochemical activity in the transsulfuration pathway and glutathione production during oxidative stress.
In men with overweight and impaired glucose metabolism or normal weight and normal glucose metabolism, a 12-week program of combined endurance and strength exercise is associated with higher insulin sensitivity, lower levels of cysteine and glutathione in the blood, and higher levels of glutamine in the blood.
In men who perform 12 weeks of combined endurance and strength exercise, a decrease in plasma cysteine levels is the most strongly linked change to improved insulin sensitivity, suggesting that sulfur amino acid metabolism is involved in the body's metabolic response to exercise.
People who engage in regular physical exercise maintain stable insulin sensitivity across the entire day, regardless of when they eat meals.
In men, regular exercise increases the activity of mitochondrial genes in muscle and fat tissue, and these changes occur alongside measurable shifts in sulfur-containing amino acids in the blood.
Not medical advice. For informational purposes only. Always consult a qualified healthcare professional before making health decisions.