High-intensity interval versus moderate-intensity continuous freestyle swimming in obese college students: A randomized controlled study protocol examining glycolipid and vascular endothelial responses.
This is a study protocol, not a results paper: it describes a planned three-arm randomized controlled trial comparing HIIT and MICT freestyle swimming with usual activity in 108 obese college students, with 6-month total cholesterol as the primary outcome and with analyses of how glycolipid changes relate to endothelial markers ET-1 and NO.
Key Findings
Methods
The paper reports no outcome data; it specifies the design of a planned randomized controlled trial of HIIT versus MICT freestyle swimming in obese college students.
The abstract says the trial 'will compare' HIIT and MICT freestyle swimming and 'will clarify' whether they differ in effects on total cholesterol (TC) and other glycolipid and endothelial outcomes.
No effect estimates, p-values, or confidence intervals are reported.
The trial was prospectively registered in the Chinese Clinical Trial Registry (ChiCTR2600121931) on April 7, 2026.
Methods
The trial will randomize 108 obese college students 1:1:1 to HIIT, MICT, or a usual-activity control group.
There will be 36 participants per group.
The rationale is that obesity in college students may be accompanied by early metabolic and endothelial abnormalities before overt cardiometabolic disease develops.
Freestyle swimming is proposed because it combines whole-body energy expenditure with low weight-bearing load.
Methods
The exercise intervention is supervised 30-minute freestyle swimming sessions three times weekly for 6 months in both exercise arms.
The two exercise arms differ in intensity pattern (high-intensity interval vs moderate-intensity continuous).
The control group continues usual activity.
Adherence and safety are assessed as secondary outcomes.
Methods
The single primary outcome is total cholesterol at 6 months, adjusted for baseline TC.
Secondary outcomes will be assessed at baseline and at 2, 4, and 6 months.
The endothelial markers named are ET-1 and NO.
Methods
The statistical plan uses ANCOVA under intention-to-treat for the primary comparison, plus mixed-effects models, multiple imputation sensitivity analyses, and multivariable regression.
The primary comparison will use analysis of covariance under the intention-to-treat principle.
Longitudinal mixed-effects models and multiple imputation sensitivity analyses will characterize outcome trajectories.
Multivariable linear regression will examine relationships between changes in individual glycolipid markers and changes in ET-1 and NO.
Conclusions
The trial aims to test whether glycolipid improvements are accompanied by changes in endothelial markers and to inform exercise prescriptions for young adults with obesity.
It will assess whether HIIT and MICT swimming differ in effects on TC and other outcomes.
The authors state the findings 'may inform safe and more precise exercise prescriptions for young adults with obesity.'
What This Means
This paper describes a clinical trial that is being planned and has not yet produced results. The researchers plan to recruit 108 college students with obesity and assign them at random to one of three groups: short bursts of hard swimming alternated with rest (high-intensity interval training), steady moderate swimming, or continuing their usual activity. The swimming groups will do 30-minute freestyle sessions three times a week for six months.
The main thing the researchers will measure is total cholesterol after six months. They will also track blood sugar and fat markers, body measurements, and two blood-vessel markers (ET-1 and nitric oxide) every two months. They plan to look at whether changes in blood sugar and fat markers go along with changes in blood-vessel markers.
Because no results are reported, this research does not yet show whether either type of swimming works better. If carried out, the study could help clarify which swimming approach might be better for young adults with obesity, and whether early metabolic and blood-vessel changes move together. The study was registered in April 2026 so its plan is publicly recorded in advance.
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Yang M, Wang J, Su X, Xiang H, Hou Y. (2026). High-intensity interval versus moderate-intensity continuous freestyle swimming in obese college students: A randomized controlled study protocol examining glycolipid and vascular endothelial responses.. PloS one. https://doi.org/10.1371/journal.pone.0360473