High-intensity interval training improves myocardial work and cardiac function in women with obesity: a randomized controlled study

Q: What are the key findings of this study?

Both high-intensity interval training and moderate-intensity continuous training improved left ventricular global longitudinal strain in women with obesity, but only HIIT significantly improved myocardial efficiency.

Q: What is the clinical evidence from this study?

Study design: RCT. Population: Obesity (n=25). Intervention: High-intensity interval training (HIIT) vs. Moderate-intensity continuous training (MICT). Primary outcome: Left ventricular global longitudinal strain (GLS) (d = 0.13, p=0.754).

Q: What does this research mean for the field?

Both high-intensity interval training and moderate-intensity continuous training improve myocardial deformation in women with obesity, but only high-intensity interval training improves myocardial efficiency. Novelty: ClaimNovelty.INCREMENTAL. Consensus alignment: ConsensusAlignment.NEUTRAL.

Caroline Ferraz Simões; Higor Barbosa Reck; João Carlos Locatelli; Gustavo Henrique de Oliveira; V.M.F. Mendes; Rogério Toshiro Passos Okawa; Jamie O’Driscoll; Jorge Mota; Wendell Arthur Lopes

doi:10.1038/s41366-026-02158-4

July 10, 2026International Journal of ObesityOpen Access

High-intensity interval training improves myocardial work and cardiac function in women with obesity: a randomized controlled study

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Key result

HIIT uniquely improves myocardial efficiency in women with obesity while matching MICT for GLS benefits.

d = +0.13
P=0.754
n=25

Why the study?

The effects of high-intensity interval training and moderate-intensity continuous training on cardiac function and myocardial work in women with obesity required investigation.

Does high-intensity interval training (HIIT) improve cardiac function and myocardial work compared to moderate-intensity continuous training (MICT) in women with obesity?

Key Points

To compare the effects of 8 weeks of high-intensity interval training (HIIT) versus moderate-intensity continuous training (MICT) on myocardial work and cardiac function in women with obesity.
Twenty-five women with obesity (Age: 28 ± 5 years, BMI: 35.03 ± 3.19 kg/m²) were randomized to 8 weeks of HIIT (n = 11; 4×4-min at 85–95% HR max) or MICT (n = 14; 41-min at 65–75% HR max).
Cardiac mechanics and myocardial strain were assessed using two-dimensional speckle tracking echocardiography, and myocardial work indices were derived from pressure–strain loop analysis.
HIIT significantly improved myocardial efficiency through a reduction in global wasted work (d = 0.64, p = 0.042; Δ = −15.23 ± 41.49 mmHg·%) and an increase in global work efficiency (d = 0.83, p = 0.005; Δ = 2.39 ± 2.43%), whereas MICT showed no significant changes in GWW (p = 0.283) or GWE (p = 0.101).
Both exercise modalities improved left ventricular global longitudinal strain (p = 0.017 for HIIT; p = 0.023 for MICT), left atrial reservoir strain (p = 0.003 for HIIT; p < 0.001 for MICT), conduit strain (p = 0.002 for both), and contraction strain (p < 0.001 for both).
Left atrial stiffness decreased in both groups (HIIT: p = 0.004; MICT: p = 0.031), while significant reductions in body weight (p = 0.002) and systolic blood pressure (p = 0.033) occurred only after HIIT.

Study Design

Type

RCT (n=25)

Blinding

Single-blind

Randomization

Computer-generated randomization sequence (1:1)

Multicenter

No

Structured PICO

Does high-intensity interval training (HIIT) improve cardiac function and myocardial work compared to moderate-intensity continuous training (MICT) in women with obesity?

P

Population

25 women aged 18-35 with grade I or II obesity and no overt cardiovascular disease who completed an 8-week exercise intervention.

I

Intervention

High-intensity interval training (HIIT) consisting of four 4-min bouts at 85-95% HRmax interspersed with 3-min active recovery at 65-75% HRmax, performed 3 times a week for 8 weeks.

C

Comparator

Moderate-intensity continuous training (MICT) consisting of 41 min at 65-75% HRmax followed by a 2-min cool-down, performed 3 times a week for 8 weeks.

O

Outcome

Cardiac function and myocardial work (MW) indices (including global longitudinal strain [GLS], global wasted work [GWW], and global work efficiency [GWE]) evaluated using two-dimensional speckle tracking echocardiography at 8 weeks.surrogate

Main Result

Standardized Mean Difference: 0.13

Absolute Event Rate: -20.25% vs -20.78%

p-value: p=0.754

In women with obesity, both HIIT and MICT improved myocardial deformation, but only HIIT significantly improved myocardial efficiency, suggesting it may be superior for targeting subclinical cardiac dysfunction.

Limitations

Reduced final sample limits statistical power for secondary outcomes
High dropout rate (~43%) may have introduced selection bias
Inclusion of women only limits generalizability to men
Absence of a non-exercise control group restricts causal inference
Physical activity, diet, and medication use were not strictly controlled
Physical activity, diet, and medication use were monitored but not strictly controlled

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Implication

HIIT improves myocardial efficiency beyond MICT in obese women; extends strain data with load-independent MW indices in this RCT.

Abstract

The purpose of this study was to investigate the effects of high-intensity interval training (HIIT) and moderate-intensity continuous training (MICT) on cardiac function and myocardial work (MW) in women with obesity. Twenty-five women with obesity (Age: 28 ± 5 years, BMI: 35.03 ± 3.19 kg/m²) were randomized to 8 weeks of either HIIT ( n = 11, 4×4-min at 85–95% of HR max ) or MICT ( n = 14, 41-min at 65–75% of HR max ). Cardiac function and strains were evaluated using two-dimensional speckle tracking echocardiography. MW indices were computed via dedicated software. HIIT significantly improved myocardial efficiency, as evidenced by a reduction in global wasted work (GWW [ d = 0.64, p = 0.042]) and an increase global work efficiency (GWE [ d = 0.83, p = 0.005]). Both HIIT and MICT reduced left ventricular global longitudinal strain (GLS, p = 0.017 for HIIT; p = 0.023 for MICT), left atrial (LA) contraction ( p < 0.001 for both), LA conduit (p = 0.002 for both), LA reservoir ( p = 0.003 for HIIT; p < 0.001 for MICT), and LA stiffness ( p = 0.004 for HIIT, p = 0.031 for MICT). HIIT and MICT both improved myocardial deformation in women with obesity. However, only HIIT improved myocardial efficiency, suggesting a potential superiority for targeting subclinical cardiac dysfunction in this population.

Discussion

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Cite This Study

Simões et al. (2026) conducted an RCT in Obesity (n=25). High-intensity interval training (HIIT) vs. Moderate-intensity continuous training (MICT) was evaluated on Left ventricular global longitudinal strain (GLS) (d = 0.13, p=0.754). Both high-intensity interval training and moderate-intensity continuous training improved left ventricular global longitudinal strain in women with obesity, but only HIIT significantly improved myocardial efficiency.

synapsesocial.com/papers/6a5330a44f7abc118aded4e7 https://doi.org/10.1038/s41366-026-02158-4

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High-intensity interval training improves myocardial work and cardiac function in women with obesity: a randomized controlled study

Key Points

Study Design

Structured PICO

Main Result

Limitations

Ask about this paper

Implication

Abstract

Discussion

Cite This Study

High-intensity interval training improves myocardial work and cardiac function in women with obesity: a randomized controlled study

Key Points

Study Design

Structured PICO

Main Result

Limitations

Ask about this paper

Implication

Abstract

Discussion

Cite This Study

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