# Acute effects of resistance-type and cycling-type high-intensity interval training on arterial stiffness, cardiac autonomic modulation and cardiac biomarkers PMID: 38212817 Journal: BMC sports science, medicine & rehabilitation Published: 2024-01-11 Authors: Wang T, Mao J, Bo S, Zhang L, Li Q ## Question Do cycling-type and resistance-type HIIT sessions with similar duration and intensity produce different acute effects on arterial stiffness, cardiac autonomic modulation, systolic blood pressure, and cardiac biomarkers in healthy young men? ## Summary In a randomized crossover study, 11 healthy active young men performed both cycling-type HIIT and resistance-type HIIT. Both protocols used 10 one-minute work intervals with one-minute recoveries after a 10-minute warmup. Resistance-type HIIT used loaded back squats and cycling-type HIIT used a cycle ergometer. The squat-based protocol reduced cardio-ankle vascular index more immediately after exercise, while both protocols produced similar temporary changes in heart-rate variability and cardiac biomarkers that returned or moved toward baseline by 30-35 minutes. ## Population - Eleven healthy active young male undergraduate physical education students from Beijing, China. - Sample size: 11 - Age: 21.36 +/- 2.46 years - Sex: Men only - Fitness level: Active; at least two systematic training sessions per week; VO2max 46.06 +/- 9.29 mL/kg/min - Health status: Healthy young men ## Methodology - Randomized crossover acute exercise trial - Acute single-session comparison with at least one-week washout between HIIT modes - Laboratory at Capital University of Physical Education and Sports, Beijing, China - Randomized and controlled study design. ## Protocol - R-HIIT. - Modality: Behind-the-neck barbell back squats. - Work intervals: 60 seconds. - Recovery: 60 seconds. - Sets or repetitions: 10 intervals, up to 30 squat repetitions per work interval. - Intensity: 20% bodyweight barbell load; metronome 60 beats/min; eccentric phase 1 second and concentric phase as fast as possible; RPE-matched to C-HIIT. - Session duration: 10-minute warmup plus 19-minute exercise intervention. - Frequency: Single acute session. - Program length: Single acute bout. - Progression: None. - C-HIIT. - Modality: Cycle ergometer. - Work intervals: 60 seconds at 90% peak power output. - Recovery: 60 seconds active recovery at 25% peak power output. - Sets or repetitions: 10 intervals. - Intensity: 90% PPO during work; 25% PPO during recovery; cadence 60-65 rpm. - Session duration: 10-minute warmup plus 19-minute exercise intervention. - Frequency: Single acute session. - Program length: Single acute bout. - Progression: None. ## Outcomes ### Average CAVI Status: improved Both protocols reduced CAVI immediately and 30 minutes after exercise; R-HIIT produced a larger immediate reduction than C-HIIT. Time x group interaction P = 0.019, partial eta squared 0.182; time main effect P < 0.001, partial eta squared 0.729; immediate R-HIIT versus C-HIIT difference -0.60 +/- 0.30, P = 0.043, d = 0.924 ### Systolic blood pressure Status: mixed SBP changed acutely over time after both HIIT modes and returned near baseline by 30 minutes, with no significant mode difference. Interaction P = 0.179; group P = 0.580; time P = 0.001, partial eta squared 0.304 ### Heart-rate variability Status: mixed lnHF and lnRMSSD decreased and LF/HF increased immediately after both protocols; parasympathetic markers remained below baseline at 30 minutes, with no significant mode differences. lnHF time P < 0.001, partial eta squared 0.782; lnRMSSD time P < 0.001, partial eta squared 0.693; LF/HF time P = 0.001, partial eta squared 0.302; no significant interactions or group effects ### Cardiac troponin-T Status: mixed cTnT increased 5 minutes after both protocols and was not different from resting value by 35 minutes; no mode difference was observed. Interaction P = 0.293; group P = 0.804; time P = 0.023, partial eta squared 0.193 ### NT-proBNP Status: mixed NT-proBNP increased 5 minutes after both protocols and was not different from resting value by 35 minutes; no mode difference was observed. Interaction P = 0.208; group P = 0.789; time P = 0.001, partial eta squared 0.334 ## Practical Insights - A 10 x 60-second, 1:1 work-rest HIIT structure can be delivered through both cycling and resistance exercise, but acute vascular responses may differ by mode. - Squat-based loaded R-HIIT may not be a broadly safe default despite favorable acute CAVI response in healthy young men. - Brief HIIT can temporarily suppress HRV recovery markers; programming should allow recovery after intense sessions. - Acute biomarker findings in healthy active men should not be used as clinical safety claims for higher-risk users. ## Limitations - Acute-only intervention - Very small sample - All participants were healthy active young men - No long-term training outcomes - Only one R-HIIT exercise mode was tested - No longer cTnT follow-up beyond 35 minutes - No explicit adverse-event reporting found ## Safety And Adherence - No explicit adverse-event results were found in the extracted full text. - Cardiac biomarkers increased transiently after both HIIT modes and returned to non-different-from-baseline values by 35 minutes. - HRV parasympathetic markers were still below baseline at 30 minutes after exercise. - The authors cautioned that the behind-the-neck squat R-HIIT protocol may cause lower-body overexertion. ## Original Sources - [PubMed](https://pubmed.ncbi.nlm.nih.gov/38212817/) (pubmed) - [DOI](https://doi.org/10.1186/s13102-024-00806-8) (doi) - [PMC full text](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10785405/) (full text) ## Agent Guidance Preserve the paper-level scope of this note. Do not generalize beyond the population, protocol, measured outcomes, and limitations above.