PMID 29618979

Research
All papers

Improvements in Attention and Cardiac Autonomic Modulation After a 2-Weeks Sprint Interval Training Program: A Fidelity Approach

de Sousa AFM, Medeiros AR, Benitez-Flores S, Del Rosso S, Stults-Kolehmainen M, Boullosa DA

Question

Does a 2-week sprint interval training program improve attention and cardiac autonomic modulation, and do responses differ by protocol fidelity?

Summary

In healthy university students, a 2-week cycle sprint-interval program improved estimated VO2max, skinfold sum, and some attention/autonomic measures. Participants who reached the target heart-rate fidelity more often showed clearer accuracy and heart-rate-variability changes.

Methodology

  • Healthy young university students allocated to sprint interval training or control
  • 91 participants.
  • Cycle ergometer.
  • Work intervals: 30 s all-out sprint.
  • Recovery: 3-4 min active no-load recovery at 60 rpm.
  • Intensity: All-out at 7.5% body mass; fidelity criterion >90% estimated HRmax.
  • 12-24 min.
  • 3 sessions/week.
  • 2 weeks.
  • Randomized controlled intervention with post hoc fidelity grouping
  • Attention, Cardiac autonomic modulation, Aerobic fitness, and Body composition were tracked.

Outcomes

VO2max

Both high- and low-fidelity sprint groups improved estimated VO2max versus baseline.

HIGH 36.9 +/- 8.6 to 41.5 +/- 6.4; LOW 38.7 +/- 9.1 to 43.5 +/- 9.7; p < 0.05 time effects

Improved

Skinfolds

Sprint groups, but not control, reduced skinfold sum.

HIGH and LOW improved skinfold sum and mean warm-up HR; control did not

Improved

Attention

Conflict effect improved in both sprint groups; accuracy improved only in the high-fidelity group.

Conflict HIGH 152.5 +/- 63.3 to 121.7 +/- 44.7; LOW 131.2 +/- 48.9 to 106.97 +/- 36.79; accuracy HIGH 96.2 +/- 6.5 to 98.5 +/- 2.6

Improved

HRV

Autonomic measures changed, with clearer resting complexity and vagal-modulation changes in the high-fidelity group.

Significant HR/HRV time effects; HIGH showed significant HR and HRV complexity changes at rest

Mixed

Insights

  • Very short all-out cycling sprint programs can move fitness and some cognitive/autonomic markers quickly.
  • Protocol fidelity matters: achieving target intensity may change which outcomes improve.
  • A low-volume sprint plan still had time and intensity demands that caused some withdrawals for lack of time.

Limitations

  • Aerobic fitness was estimated indirectly
  • Incidental physical activity and diet were not controlled
  • Training/sport background was not fully described
  • Estimated HRmax was used for fidelity classification
  • Short intervention

Safety

  • The article did not clearly report adverse-event incidence.
  • Seventeen intervention participants and one control withdrew because of lack of time.