PMID 34747202

Research
All papers

Divergent serum metabolomic, skeletal muscle signaling, transcriptomic, and performance adaptations to fasted versus whey protein-fed sprint interval training

Aird TP, Farquharson AJ, Bermingham KM, O'Sulllivan A, Drew JE, Carson BP

Question

How do fasted, whey protein concentrate-fed, and whey protein hydrolysate-fed conditions affect acute and 3-week metabolic and performance adaptations to sprint interval training?

Summary

In recreationally active but aerobically untrained men, 3 weeks of Wingate sprint interval training improved mitochondrial enzyme activity and aerobic/anaerobic performance regardless of whether sessions were done fasted, after whey protein concentrate, or after whey protein hydrolysate. Protein feeding changed acute amino-acid and muscle-signaling responses and did not blunt training adaptations.

Methodology

  • Twenty-eight healthy recreationally active male participants aged 18-35 years who were aerobically untrained, protein sufficient, and nonobese.
  • 28 participants.
  • Cycle ergometer sprint interval training.
  • Work intervals: 30 s all-out sprint.
  • Recovery: 4 min active recovery.
  • Intensity: All-out against resistance equivalent to 7.5% body mass.
  • 5-min warm-up, sprint/recovery set, 3-min cool-down.
  • Typically 3 sessions/week with 48-72 h between sessions.
  • 9 sessions over 3 weeks.
  • Randomized double-blind parallel-group nutrition and sprint interval training study
  • Serum amino acids and metabolites, Muscle gene expression and signaling, and Performance were tracked.

Outcomes

Amino acids

WPH and WPC increased amino-acid availability versus fasted conditions.

Protein feeding increased 17 amino acids plus total BCAA, EAA, AA, and NEAA tAUC versus FAST (all p<0.05); WPH exceeded WPC for several amino-acid summaries

Improved

Gene expression

Protein did not blunt acute increases in key mitochondrial/metabolic genes; WPH enhanced CD36 response.

PGC-1alpha, PDK4, SIRT1, and PPAR-delta increased after acute SIT independent of nutrition; WPH beneficially altered CD36 mRNA expression

Mixed

Mitochondrial enzymes

Citrate synthase and beta-HAD activity increased after 3 weeks in all nutrition groups.

Authors reported augmented CS and beta-HAD after training with no nutrition-condition effect

Improved

Performance

Aerobic and anaerobic performance improved after 3 weeks regardless of nutrition condition; WPH showed preliminary advantages for some anaerobic components.

Training improved aerobic mean power and Wingate measures within groups; mean-power adaptations did not differ significantly between nutrition groups

Improved

Insights

  • Preexercise whey protein did not compromise short-term SIT performance or mitochondrial enzyme adaptations compared with fasted training.
  • Fasted SIT is not required to preserve acute mitochondrial gene-expression responses in this context.
  • The study is mechanistic and uses invasive measures; practical claims should be modest.

Limitations

  • Small parallel groups and some outcomes had n=8-10 per group.
  • Only healthy young men.
  • Only 3 weeks of training.
  • Some between-group effect sizes suggested limited power.
  • Industry funding from Carbery Food Ingredients.

Safety

  • Across 241 exercise sessions, 10 incidences of gastrointestinal distress were observed.
  • Participants were informed of risks and screened with PAR-Q/7D-PAR.