Table 3 HIIT studies in cardiovascular disease

Bailey et al. (2018) [47]

Frequency: Single session

Intervals: 12 intervals at 70% PPO for 1 min

Rest: 1-min recovery at 10% PPO

Modality: Cycle ergometer

Brachial artery FMD increased after MCT and decreased after HIIT in both AAA and healthy cohorts.

Not given

Currie et al. (2012) [48]

Frequency: Single session

Intervals: 10 intervals at 80% PPO for 1 min

Rest: 10% PPO for 1 min

Modality: Cycle ergometer

Mean HR and total work performed were higher in MCT compared to HIIT. In spite of this, there was no significant difference between the two interventions in the increase of brachial artery FMD 60 min post-exercise (absolute or relative values).

Compliance: All completed HIIT; 2 could not complete MCT due to volitional fatigue.

Currie et al. (2013) [49]

Frequency: 2×/week for 12 weeks

Intervals: 10 intervals at 89% PPO for 1 min

Rest: recovery at 10% PPO for 1 min

Modality: Cycle ergometer

Relative increase in FMD and improved VO_2peak post-training in both groups with no significant difference between groups.

Dropouts: 4 (not included in results): 3 had changes to beta-blockers and one was put on calcium channel blocker.

AEs: None in either group

dos Santos et al. (2018) [50]

Frequency: Single session

Intervals: 4 intervals at 85–90% HRR for 4 min

Rest: 2-min active recovery at 50% HRR

Modality: Cycle ergometer

The HIIT session promoted a greater systolic hypotensive effect compared to the MCT session. There was no significant difference in post-exercise diastolic hypotension between groups.

Dropouts: Of 39 participants recruited, 20 did not attend one of the exercise sessions (not mentioned which one), 4 did not reach target zone for the exercise and were excluded.

Acceptance of protocol: Participants subjectively reported that their comfort level was higher in HIIT than in MCT.

Guiraud et al. (2009) [51]

4 SIT protocols:

A) 15-s intervals (15-s passive rest: 0% MAP)

B) 15-s intervals (15-s active rest: 50% MAP)

C) 60-s intervals (60-s passive rest: 0% MAP)

D) 60-s intervals (60-s active rest: 50% MAP)

Frequency: Single session

Intervals: 100% MAP

Time: As long as tolerated or 35 min maximum

Modality: Cycle ergometer

All protocols had similar time spent above 80% VO_2peak. Protocol A had a significantly lower rating of perceived exertion at the end of the session. Significantly, 63% of participants were able to complete the entire duration of this exercise (compared to 16%, 42%, and 0% of protocols B, C, and D, respectively. 18 out of 19 participants rated protocol A as both the preferred protocol.

Dropouts: 1 due to injury due to recreational activity and not included in results

AEs: 2 patients had vagal episodes after one HIIT protocol. 3 subjects presented myocardial ischemia and developed mild angina during the SIT exercises. Maximal ST-depression never exceeded 2mm. Symptoms and ST-depression resolved during passive recovery.

Helgerud et al. (2009) [52]

8-weeks of plantar flexion HIIT (alternating legs, 4-min intervals at 80%Wmax) followed by 8 weeks of treadmill HIIT:

Frequency: 3×/week for 8 weeks

Intervals: 4 intervals at 90–95% HR_peak for 4 min

Rest: 3-min active rest for recovery

Modality: Treadmill

Aerobic capacity and CV function were improved after plantar flexion training (plantar flexion VO_2peak increased 14.8%, treadmill VO_2peak increased 16.8%, time to exhaustion increased 58.5%, PPO increased 61.4%). These changes were increased by further treadmill training (additional treadmill VO_2peak increase by 9.9%, time to exhaustion increased 16.1% and Q and SV increased by 33.4% and 25.1%, respectively).

Compliance: Participants excluded from results if they did not attend at least 85% of training sessions.

Moore et al. (2020) [53]

Frequency: ≤ 40 sessions in 10 weeks

Interval: ≤ 40 min targeting 70–85% HR_max

Rest: Breaks as needed

Modality: Stepping

Average steps per day in HCT (5777 ± 2784) were significantly greater than during usual care (3917 ± 2656; p < 0.001). Statistically different and clinically meaningful changes in self-selected speed (0.39 ± 0.28 versus 0.16 ± 0.26 m/s) and fastest gait speed (0.47 ± 0.41 versus 0.17 ± 0.38 m/s; both p < 0.001) were observed following HCT vs usual care.

Intensity achieved: HCT participants on average maintained the target intensities for over 30% of each session.

AEs: Falls outside of therapy were most commonly reported (9 in control and 11 in HCT). During usual care only there was a report of infection and 7 transfers to acute care for medical issues, syncope, and unknown reasons.

Nepveu et al. (2017) [54]

Frequency: Single session

Intervals: 3 intervals at 100% Wpeak for 3 min

Rest: recovery at 25% Wpeak for 2 min

Time: 15 min

Modality: Recumbent stepper

Motor task skill learning and retention was higher in HIIT group (9% improvement vs 4% decay in control). A maximal graded exercise test did not result in significant changes in corticospinal excitability.

Dropouts: Out of 22 participants included in the study: data were lacking for 1 retention test and for 2 transcranial magnetic stimulation tests.

Reichert et al. (2016) [55]

Frequency: 2×/week for 28 weeks

Intervals: 6–12 intervals at Borg scale 15–18 for 2–4 min

Rest: recovery for 0.5–1 min

Modality: Deep water running

Similar and significant improvement seen in both groups post-exercise in measures of functional fitness: foot up-and-go (12% in both groups), flexibility of lower limbs and strength in upper and lower limbs (number of repetitions improved by over 40% in both groups), and 6 min walk test (12% in HIT group, 4% in MCT group). Both systolic and diastolic BP was significantly decreased in both groups post-training. This change was similar between both groups for systolic pressure but greater in diastolic pressure after continuous training.

Dropouts: HCT: 1 allergy, 1 surgery, 2 discontinued, 1 refused to participate in the assessments; from HIIT: 2 excessive absence, 3 abandoned the study.

Compliance: Samples that did not obtain at least 80% frequency in the sessions were excluded.

Sosner et al. (2016) [56]

Frequency: Single session

Intervals: 15 s at 100% PPO

Rest: 15-s passive recovery

Time: 2× 10-min sets

Modality: Cycle ergometer (on dryland or immersed in water)

Similar decrease in systolic BP was seen in all groups 4 h after exercise. 24-h ambulatory BP was significantly decreased post-exercise only in HIIT groups, with increased change seen in immersed (compared to dryland) protocol.

Not given

Tew et al. (2017) [57]

Frequency: 3×/week for 4 weeks

Intervals: 8 or 4 intervals at the Rate of Perceived exertion for legs: 5, or the Rate of Perceived exertion for chest/breathlessness: 7 for 2 or 4 min

Rest: active recovery for 2 min

Modality: Cycle ergometer

Primary—see feasibility and tolerability. Secondary—No significant change in cardio-respiratory fitness was seen between groups. Difference in post-op morbidity, mortality, and quality of life between groups was trivial to small.

Dropouts: Rate of screening: 100%; Eligibility of participants: 43.2%; Recruitment: 22.1%; Retention: 91%; Outcome completion: 79–92%

Compliance: Overall attendance: 75.8%. Exercise intensity was generally lower than what had been intended.

AEs: One participant experienced prodromal symptoms on 4 occasions when power output increased over 80 W. Symptoms resolved by decreasing workload.

Acceptance of protocol: The program was scored as “enjoyable.”

Windsor et al. (2018) [58]

Frequency: Single session

Intervals: 12 intervals at 70% PPO for 1 min

Rest: 1-min recovery at 10% PPO

Modality: Cycle ergometer

Healthy subjects had higher mean power outputs in both MCT and HIIT groups. Greater anti-inflammatory response was seen in HIIT compared to MCT groups. This was further augmented by AAA. Post-MCT, there was a modest and transient increase in IL-6 and MMP-9 in healthy and AAA patients. 90 min post-HIIT, there was a decrease in MMP-9 in both populations and lower TNF-α in AAA group.

Not given