PMID 25626864

Research
All papers

Age related vascular endothelial function following lifelong sedentariness: positive impact of cardiovascular conditioning without further improvement following low frequency high intensity interval training

Grace FM, Herbert P, Ratcliffe JW, New KJ, Baker JS, Sculthorpe NF

Question

Can cardiovascular conditioning and then low-frequency HIIT improve age-related endothelial function in lifelong sedentary older men?

Summary

In older sedentary men, 6 weeks of supervised cardiovascular conditioning improved vascular endothelial function, while adding low-frequency HIIT afterward improved aerobic capacity but did not further improve flow-mediated dilation. Lifelong exercisers served as a comparison group and maintained high vascular function.

Methodology

  • Older men classified as lifelong sedentary or lifelong exercisers.
  • 44 participants.
  • Wattbike cycling.
  • Work intervals: 30 seconds.
  • Recovery: 3 minutes active recovery at low resistance.
  • Intensity: 40%-50% peak power; target peak HR >90% HRR.
  • 150 minutes/week target during conditioning.
  • Once every 5 days.
  • 6 weeks.
  • Prospective nonrandomized cohort intervention with lifelong exerciser comparison group
  • Flow-mediated dilation, Aerobic capacity, and Vascular biomarkers were tracked.

Outcomes

FMD

Sedentary men improved FMD after conditioning.

SED phase A to B p<0.001.

Improved

FMD

Low-frequency HIIT did not further improve FMD after conditioning.

SED phase B to C p=1.0.

No clear change

Aerobic capacity

Low-frequency HIIT improved aerobic capacity in both groups.

About +8.3% SED and +7.4% LEX.

Improved

Insights

  • For older sedentary users, build conditioning before HIIT.
  • Low-frequency HIIT may improve aerobic capacity even if vascular FMD gains have already occurred with conditioning.

Limitations

  • Nonrandomized cohort design.
  • No negative control for the second 6-week phase.
  • Men only.
  • Biomarker analyses were not the primary powered endpoint.

Safety

  • Applicants required GP approval and PAR-Q screening; three applicants were advised to withdraw before enrollment because of risk.
  • Sedentary participants completed 6 weeks of conditioning before low-frequency HIIT.
  • Low-frequency HIIT had 100% adherence after conditioning and was described as well tolerated; no adverse events or injuries were reported.