# Effect of High-Intensity Interval Training on Body Composition, Cardiorespiratory Fitness, Blood Pressure, and Substrate Utilization During Exercise Among Prehypertensive and Hypertensive Patients With Excessive Adiposity

PMID: 33192554
Journal: Frontiers in Physiology
Published: 2020-10-19
Authors: Delgado-Floody P, Izquierdo M, Ramírez-Vélez R, Caamaño-Navarrete F, Moris R, Jerez-Mayorga D, Andrade DC, Álvarez C

## Question

What are the effects of 16 weeks of HIIT on body composition, blood pressure, cardiorespiratory fitness, and exercise substrate utilization in adults with excessive adiposity and normal, prehypertensive, or hypertensive blood pressure?

## Summary

Physically inactive adults with overweight or obesity completed 16 weeks of supervised cycling HIIT, grouped by baseline blood pressure. The program improved VO2max and reduced systolic blood pressure across blood-pressure groups, with particularly relevant changes among hypertensive participants, but the study lacked a non-exercise control group.

## Population

- Physically inactive adults with overweight or obesity, distributed by baseline blood pressure into normotensive, prehypertensive, and hypertensive groups.
- Sample size: 42
- Age: H-CG 40.7 +/- 11.0, H-PreHTN 37.6 +/- 12.0, H-HTN 47.7 +/- 12.0 years
- Sex: 21 female and 21 male
- Fitness level: Physically inactive; not meeting low/moderate or vigorous physical-activity recommendations
- Health status: BMI 25-39.9 kg/m2; normotensive, prehypertensive, or clinically hypertensive; medically authorized for exercise

## Methodology

- Pragmatic interventional study with groups defined by baseline blood-pressure status
- 16 weeks
- Supervised in-person exercise intervention using a magnetic resistance static bicycle

## Protocol

- Cycling HIIT.
- Modality: Magnetic resistance static bicycle.
- Work intervals: 1 minute.
- Recovery: 2 minutes passive recovery on the bicycle without pedaling.
- Sets or repetitions: 10 repeated intervals per session.
- Intensity: Maximum-intensity cycling corresponding to 80-100% HRmax and modified Borg 8-10.
- Session duration: About 30 minutes of intervals/recovery per session, with 10 minutes effective work and 20 minutes passive recovery.
- Frequency: 3 sessions per week.
- Program length: 16 weeks.
- Progression: Participants completed 3 familiarization sessions; workload was individualized by HR and Borg intensity rather than fixed watts.

## Outcomes

### VO2max
Status: improved
VO2max improved in all blood-pressure groups, with the largest numerical gain in hypertensive participants.

H-CG +3.34, H-PreHTN +3.63, H-HTN +5.92 mL/kg/min; time x group p=0.083.

### Systolic BP
Status: improved
Systolic blood pressure decreased in all groups.

H-HTN -8.70 mmHg, H-CG -7.14 mmHg, H-PreHTN -5.11 mmHg; intergroup p=0.566.

### Diastolic BP
Status: mixed
Diastolic blood pressure decreased most clearly in normotensive participants.

H-CG -5.43 mmHg; H-CG decrease was significantly greater than H-HTN, p=0.032.

### Body composition
Status: improved
Body mass decreased in all groups, with body fat reduction reported in hypertensive participants.

Body mass: H-CG -1.76 kg p=0.032, H-PreHTN -1.99 kg p=0.010, H-HTN -2.79 kg p=0.002; body fat H-HTN -1.38%, p=0.015.

### Fuel use
Status: no clear change
RER and carbohydrate oxidation did not significantly change; fat oxidation increased only in the normotensive group without group interaction.

RER and CHOox p>0.05; FATox H-CG +11.65% but time x group p=0.910.

### Correlations
Status: mixed
Most BP, fitness, and substrate changes were not correlated, except SBP versus VO2max in hypertensive participants.

H-HTN SBP change versus VO2max change R2=-0.444, p=0.045; otherwise no significant correlations.

## Practical Insights

- A simple 1-minute hard, 2-minute passive recovery cycling format can improve fitness and blood pressure over 16 weeks in inactive adults with excess adiposity.
- The protocol used only 10 minutes of high-intensity work per session but required supervised cycling and clinical screening.
- Blood-pressure benefits should not be presented as definitively caused by HIIT alone because there was no non-exercise control group.

## Limitations

- Not randomized.
- No true non-exercise control group.
- Nutritional habits were not evaluated; participants were only reminded to maintain baseline dietary habits.
- IPAQ score was screened but not incorporated in analyses.
- No vascular function test was included.
- Indirect calorimetry was used for estimating fat and carbohydrate oxidation instead of more accurate tracer methods.

## Safety And Adherence

- The article reported medical authorization, ECG and dyspnea/cardiac exclusions, and exclusion for adherence below 80%.
- No explicit adverse-event results were provided.

## Original Sources

- [PubMed](https://pubmed.ncbi.nlm.nih.gov/33192554/) (pubmed)
- [DOI](https://doi.org/10.3389/fphys.2020.558910) (doi)
- [PMC full text](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7604322/) (full text)

## Agent Guidance

Preserve the paper-level scope of this note. Do not generalize beyond the population, protocol, measured outcomes, and limitations above.